Moonbase Arcade Restoration - Gone Wrong

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[@sw6188]

I'm a TV technician - I started working on CRT sets (including monitors) in the late 1970s and continued into the early 2000s. First thing I will say is don't beat yourself up for installing the replacement IC backwards. I have done that a number of times myself, it's easy enough to do! As for the failure of the replacement, there's a few things I would be checking. The first is the DC resistance of the vertical coil on the yoke. It should be between 2 - 7 ohms (and 4 - 15 mH if you have an inductor tester). Also check it for shorted turns. That will kill a vertical output IC in short time. Next check the voltage rail going to pin 2 or 10 - should be within the range of 9 - 18 volts (20 volts absolute max). It is possible (can't be ruled out) that when you powered the board up with the IC installed backwards it compromised it. The results of such a situation can't be predicted. I have had ICs survive just fine, others fail immediately (let the magic smoke out) and some which worked fine for a while only to die further down the track. Those dark stains on the original chip are indicative of an IC that's been running really hot. I suspect the thermal connection to the heatsink wasn't great. It needs to be very well thermally bonded. Use the white thermal paste. Lastly I would question the authenticity of the replacement IC. Where did you source it from? If it's from eBay or Aliexpress etc it's likely a chinese fake. They'll often work for a while then go toes up after a period (as this one did). I would attempt to find a genuine IC from a known seller to be absolutely sure it's a good one. As far as I can see, the KA2130 is a pin-for-pin replacement for the uPC1031H2. Looking forward to part 2 of this saga.

[@cheyannei5983]

Is it possible the power supply is just too high voltage?

[@telbee]

Yeah, first thing I thought too - Partly shorted yoke would burn that IC up . I half-expected Adrian Black to check that on his video..

[@sw6188]

@@cheyannei5983 Yes, it is possible but unlikely. If there was more than 20 volts on the vertical IC it would mean the rest of the supply rails were likely high as well and there'd be other weird symptoms (or capacitors starting to vent off). In any event, you would check the voltages as a matter of course before replacing any ICs like this.

[@sw6188]

@@telbee I've seen more than my share of yokes with shorted turns over the years but in this instance I would want to know that the vertical IC is a genuine part - there are way too many chinese fakes on the market and this is typical of what they do. If they work at all, they'll run for an hour or two then fail.

[@YamanoteSensei]

It seems like a frequency issue. Caps and resistors together can be used to create frequency. If there's a resistor that went weird then the SIP would work until it gets damaged again from too high current then you'll get the same issue. Something going to the SIP is probably messed up and replacing that SIP will cure the problem for long enough for it to get fried again. I'm thinking blown resistor.

[@BoshMind]

For a clone of Space Invaders, the machine is nearly identical to a real one. I fixed one up a few years back and the internals are nearly 1:1. Although mine had a breakup letter in it instead of a dime lol.

[@TheTurnipKing]

Slightly interesting that it's Nichibutsu too. They went on to do Moon Cresta.

[@silverneon4675]

Didn’t expect to see you here, Bosh lol

[@jeremyaster7470]

I wanna see that letter.

[@DrawsomeDrawer]

wtf are you doing here?

[@FreddyB41]

Love you Bosh!

[@Micmeat]

The rolling mode has to be one of the most innovative difficulty toggles of all time.

[@joeycoursey7913]

honestly seems like a fun mode for old arcade games to give a challenge

[@ahsokatano6059]

new feature

[@xcloudx01alt]

not only do they get faster and move horizontally.. but at any moment they could go EVEN FASTER HORIZONTALLY!

[@MarkMcDaniel]

Dark Souls mode confirmed.

[@nappeywappey]

"It's not a bug, it's a feature!"

[@fitfogey]

I personally love your humility in including the mistakes. Nobody is perfect. It gives us an understanding in the substantial time it can take to try and get something to work. I really value your channel.

[@xcloudx01alt]

We believe in ya 8bitguy

[@nickryan3417]

Same here. It's also much more realistic than so many channels that only show the success and not all the huge amount of preparation and trial and error that went into the finished article

[@sage_x2002]

This is just an idea, and probably odd, but hear me out. You remember how the sticker on the side said it is made for 100V 50/60Hz? Well... Everything on it indicates it definitely was made for the Japanese Market, and maybe the place this has been in before, actually ran it at 100V AC. My guess would be, use a multimeter, and look up the pin out of the IC you replaced, as well as some other connections. The parts can't exceed certain voltages. If they do, the power supply gets too much power, and doesn't step it down properly. It could also be a faulty power supply, but given this machine has a sticker on it that says "Made in Japan" and has a Japanese start button, I would presume this really was made for that very specific voltage and was never changed. The arcade this has been at, might have run it at 100V, then they sold it or got rid of it, someone else tried to use it at 120V, which broke it, so they got rid of it and eventually you got it. I just believe, it certainly wouldn't hurt to try and check some DC voltage readings on the board, to see if that is your issue. Hope that helps ^^

[@elysiansaluki1]

That was the exact thought I had through the entire video and the transformer likely has different live legs representing different input voltages

[@talis84]

My thought as well.

[@Dr.Quarex]

I did wonder why he was so quick to discount the idea that it was made for the Japanese market, especially when seeing literal Japanese text on the game buttons

[@SirFrag32]

This actually makes a lot of sesne.

[@BadMax02_VR]

We had a similar issue here in germany with very nice vintage Sound Amplifiers, where germany used to be 220v and than they raised the voltage slightly to 230v going up to almost 240v in the night from experience, the amps still work but they get quite a bit warmer than they were suppose to back in the day, which just makes them break alot faster, i mean they lasted 50y and now they only lasting for like 1-2 more years, naaah. everytime i get one of these amps i immediatly change the voltage stepping to the transformer from 220v to the already existing but unused 240v stepping on the transformers which makes them run noticibly cooler. Noted: 220v to 240 is only half the amount of more volts than 100v to 120v is so that would mean it would be a even bigger issue in the case of this arcade table. back than they probably used an external 120v to 100v transformer which arent that expensive because they are quite basic just a tranformer with a multiple of 6:5 wiring ratio and like 100-200w of power capability, back than when copper was cheap. i would suggest seeing if the integrated transformer maybe already has wiring ready to convert it to 120v where you would just need to unsolder the power wires and solder them to another wire pair on the transformer

[@GeekmanCA]

IT Pro here - Anyone pointing and laughing at a small mistake after weeks of gruelling troubleshooting has never been through a frustrating troubleshooting process. That's life in tech. There's a fine line between people jokingly taking-the-piss at you for putting a part in backwards versus acting like that's any reflection on your actual ability or competence.

[@vadermasktruth]

I concur.

[@Rob_M_jr]

exactly....and we all have to start somewhere... instead of some of these armchair warriors pointing and laughing, how about engaging in a more positive fashion and throwing out some tips, or suggestions on possible troubleshooting techniques. when I started working on electronics in my teens, I definitely failed more than I succeeded. I'm in my 40s now, and enjoy being able to save old electronics from the landfills.

[@Colt45hatchback]

I agree, being stumped on a seemingly non issue or small intermittant fault is frustrating, then when people have absolutly no idea about anything make fun of how long it took, its very annoying as theres nothing you can say or do to educate them. Having said that, i am looking forward to it being thrown in the trash on another channel 😂

[@vanguze]

I have learned to get another set of eyes on an issue if it's stumping me. Means I probably missed something stupid lol.

[@--Zook--]

not just tech life. Ive been stumped by house issues, car issues, and tech issues over the years. learned a lot from all of it. Most of my working life there was no youtube to fall back on.

[@Xsses]

You have no idea how important your videos are. You really keep the spirit of those who have restoration problems like you. Sometimes fixing something old is soooooooooooooooooooooooooooooooooooooo hard and seeing someone having similar problems means that at least I am not the only one.

[@RetroRepairGuy]

I agree 100% and at times even I find it difficult after over thirty years. Some of this stuff is beyond repair and I don't give up.

[@skittstuff]

Honestly, I prefer watching people make mistakes and figure out what went wrong. The learning process (and accepting that it's okay to make mistakes) makes you seem more human and humble. Nobody is going to be perfect. And certainly to an outsider who doesn't fix electronics like you, I think you're doing a fine job. So fun to watch while I'm taking boring school notes!

[@BrendanWeibrecht]

As a software developer, I absolutely do not envy the 40-minute feedback cycle you had here! I really struggle beyond like 20 seconds, haha

[@HOLLASOUNDS]

Looks like a Snooker table design, the local pub has a table with coin insert that drops the balls.

[@buras.]

​@@HOLLASOUNDS i

[@ericbarlow6772]

Former software developer here and I definitely know how maddening it can be, especially when you finally figure it out and then realize how close you were many steps ago and went down the wrong path.

[@fake12396]

Atari developers throughout the 70s and 80s had to manually burn and replace EPROMs every time they wanted to test their new code...

[@VOIP4ME]

Try FPGA development. 5.5 hours to build and test my current design on a 10-core Intel i9. We try to simulate everything we can, but for some high-level changes that's not feasible or, in some cases, even slower.

[@eDoc2020]

I think it's a power supply diode, here's why: From my experiences with TVs I can tell you have 60Hz ripple in the monitor circuitry. Since the fault is causing decreased picture size it's most likely in the power supply circuitry. The odd thing is the monitor has a full bridge rectifier so regulation issues _should_ be manifesting at 120Hz. One explanation is that one of the diodes in the rectifier is intermittently failing open. Since Adrian was testing with DC instead of AC input such a failure likely would not have shown up in his testing.

[@morphman86]

Could it be because it's running at a higher voltage than specified?

[@deathdeathrevolution3499]

This seems incorrect to me and here's why: for one, the chip replacement fixed the problem for a time and then failed again meaning it most likely was getting too high of a voltage. And for another, the chip that was pulled out was visibly damaged and replacing it again fixed the issue for a bit and then failed in exactly the same way. I presume, with my knowledge of chips, checking any pot for voltage or checking the other components that are involved in the power rail and replacing them would fix the problem. If you have a better argument for your theory though feel free to say something. If I'm severely wrong it would be helpful to at least know.

[@SYS49152]

@@deathdeathrevolution3499 I was also thinking overvoltage or a problem related to the power supply; the sticker mentions 100V, as far as I know US is 120V so potentially the difference could be over 30V once rectified. But I'm taking for granted he tested the voltage before installing the chip.

[@Ronaldo-eu1nz]

Yo🔥kzbin.info/www/bejne/qJWtapWpg5x9d9k..

[@seregruin]

He did change the power cable in the very end and if the video chronology is correct, it broke after that.

[@Jordan-ez2gn]

These restoration videos are so interesting and weirdly therapeutic. People online have a tendency to be overwhelmingly negative, don't let it get ya down.

[@raven4k998]

that plug was custom made you scare that crap out of if you thought about plugging it in🤣🤣

[@newkillergenius]

Never- NEVER reach into the voltage area of a cocktail machine monitor and make adjustments while your other arm is grounded to the frame. 8:18 Love your channel David, take care.

[@Psychlist1972]

I'd rather see mistakes and folks own up to it, rather than see a problem, and then there's a magic cut and it's fixed without any discussion. Thanks for keeping it honest. As to the unit itself: I recommend checking the output voltage of that power transformer. I have a lot of old synths from Japan, and they work on US voltage, but heat up way more than they should (some have tuning issues if run on US voltage). It's really a good way to have them fail early, and maybe toast some unobtanium. If the voltage coming out of the transformer is too high, just run it off of a 120v->100v step-down transformer external to the cabinet, or maybe even down in the coin drawer. PS: That pic at 19:43 is, erm "inspired", right from early Yamato/Star Blazers. It's the Comet Empire.

[@markevans2294]

Looking at around 4:56 you can see the transformer is marked with 220, 230 and 240v taps. Thus it's more likely a case of moving a wire on the transformer primary, rather than using an additional transformer.

[@Legend813a]

Star Blazers was the bomb, had to run home from school and turn the big antenna towards a distant city to watch it.

[@des-geek]

At first I thought it was some sort of generic space art but now that you pointed out I can't stop seeing the Gatlantis' White Comet.

[@ffsireallydontcare]

The comet empire was right there and I didn't see it! Something in my brain registered though, I could feel it trying to tell me something at the time...

[@Psychlist1972]

@@Legend813a Star Blazers and Force Five (New England-area, and a couple others, mashup of serveral different giant robo anime series) were my hour of *my* TV time when I was younger. Well, that and my weekly COSMOS on Channel 2.

[@barberamixing]

Have you considered checking for the proper output voltages from the power supply? Not only to check for functionality but it would also tell you if it really is a 100v unit or not. You mention it burning out chips, maybe because the voltage is too high and you do need a step down transformer. Love your stuff! Hope you get it figured out.

[@DodgeHooker641]

I 2nd this! As you stated in the video, it was manufactured for the Asian market using 100 VAC and NOY the USA market using 120VAC, so that 20 volts extra, when put through the stepdown transformer may still be providing too much input voltage on the video driver circuit and thus blowing your video IC chip!!! Go test your voltages on board and see what you get! And since you have a complete electrical schematic, you may need to determine what component values you'll need to swap out to allow use of 120VAC that'll prevent circuit damage on board

[@christophernewman8741]

The fact that it powered on and operated would highly suggest it was converted but I would check the conversion components.

[@Rob_M_jr]

I 3rd this! the first rule of testing electronics. thou shall check voltages. and I agree that if it was never modified to run in the US, that could be a possible cause of failure. I have seen people fry thier Famicom consoles by not stepping them down to 100v.

[@andygozzo72]

@@DodgeHooker641 they're be a regulator somewhere before or on the monitor board so unlikely that would have been the problem directly, but the extra voltage will result in higher heat dissipation within the regulator circuit which may be a problem, this may be the issue, regulator passing too high voltage out, maybe NOT due to excess mains but coincidental failure of a zener? i see nowhere in the video that any voltages were checked when in use....

[@christophernewman8741]

The Two tax tags showed it operated in the U.S for atleast two years that would be a lot of run time for over voltage.

[@dhpbear2]

2:17 - The original 'two-step verification' :)

[@FlashFireSix]

After replacing 5 IC’s on a vintage Marshall amplifier that kept mysteriously killing them during use, I found it was just as simple as faulty diodes sending voltage where they shouldn’t. Total shot in the dark but maybe check/replace any of them.

[@maccxxster]

Agreed. Often a power burst while turning the unit on, with leaked caps still in the circuit, will kill ICs, transistors, and, ofc. diodes, too!

[@eekee6034]

Usually, I'd upvote a comment like this, but I just saw the bit where he said he'd tested every diode. XD

[@FlashFireSix]

@@eekee6034 oops, guess I missed that part

[@holymackerel]

I always appreciate when people include their hardships and mistakes. It adds authenticity.

[@michaelbutta4764]

@The 8-Bit Guy, I don’t know if you will ever see this comment David but I want it said regardless: I THOROUGHLY appreciate your videos, ESPECIALLY the moments in which you discover an error in the process. It’s largely because of the honest, detailed record of your process in refurbishing electronics (a discipline of which I only have a passing interest) that I have followed your content over the years. Your candor and transparency are refreshing and I wouldn’t have you change a thing. Thank you sincerely for the effort you invest in my entertainment!

[@navithefairy]

Same, i really love to see the debug process on how to find the actual problems. Not just oh i replaced this and it worked again.

[@jama211]

Well said!

[@annyonny1224]

Yeah yeah, but it's not a good look to chastise his own audience by deeming certain thereof "arm chair warriors" or whatever, or to otherwise complain about his own comments section. He should recognize that he is not that special, his grievances there are commonplace on any kind of channel like this. And overall one can choose to be butthurt about the obnoxious attitude of commenters who know the topic of a video better than who produced it, but the truth may just be that those commenters too are contributing something in the form of their knowledge which is a good thing.

[@michaelbutta4764]

@@annyonny1224 You can interpret it that way if you choose to. I personally feel that’s a unfair characterization of a guy who uploads his experiences tinkering away at a hobby he enjoys and asking for nothing in return. I don’t believe he was referencing anyone other than that certain brand of comment section troll that stir shit for lulz and not those genuinely interested in contributing instructive feedback.

[@darren6202]

@@annyonny1224 Your comment suggests you're one of the 'Armchair Warriors' he's referring to, else you wouldn't have got so offended. Cheer up!

[@minnesotaboy]

I love it when you keep the mistakes in the video, as it tells a much more real and well rounded story of whatever project you are working on. Any project I have ever done includes mistakes, and you are right that making them is where learning comes from and also provides a real sense of satisfaction when you figure it out. Keep it up!

[@appliedengineering4001]

Dave. That putting the IC in backwards was a honest mistake on your part. In my decades of working with electronics. I can tell you right now that the fact that that board was designed to hold that chip in backwards was a violation of industry standards. Any time you have an electronic component that need mounting to a heatsink. You always mount the component with the label side facing the same way as the mounting screws. I'm surprised that you haven't came across some DIP IC sockets mounted in backwards on some of your old computers you work on. I had this happen to me a few years ago when I ended up frying a very expensive microprocessor because the service tech before me decided to put the IC socket in backwards on the board. Had I look closer and saw the silkscreen markings or remembered the orientation that the old IC was in. I would've spotted the mistake.

[@peterferguson2344]

I was thinking that myself, I can't recall ever mounting a chip with the ID markings side facing the heatsink

[@mjouwbuis]

@@peterferguson2344 it isn't really facing the heatsink though, as the heatsink has a cutout. I don't believe there's an industry standard for such cases.

[@Lamster66]

@@mjouwbuis However he did have the data sheet for both the old and the new device and the silk screen on the board. As well as that you can see in the video which way round the device was mounted originally. Schoolboy error I'm affraid he's lucky that it didn't damage the new device or take the board out altogether.. As for industry Standard Whilst we might all now get our asses kicked because it doesn't comply to IPC J-STD back in the 1970s and 1980's you were lucky if the thing was soldered up properly in the first place or earthed properly Especially American electronics equipment had to be the shoddiest workmanship on the planet before the chinese started making stuff. The only two electric shocks I've had working on stuff has been US built equipment and on both occasions got shocked taking the covers off. Ironically to rewire it for 240V opperation

[@mikkelbreiler8916]

Looking at the video at round 10:17 he unscrewed from the textless side. Then at 10:33 he is screwing in the new part text facing him. Honest mistake. But sending the whole thing off to a nother guy who taes a look and point directly at the mistake must be one of those things life throws at you and makes you smiles becasue afterall we're only human.

[@Lamster66]

@@mikkelbreiler8916 Yep just spent about 3hrs staring at a circuit diagram trying to work out what the design guy was thinking of when he designed it? And just when you think you've understood it, the scope tells a different story. Ironically the fault ought to be a simple fix but the way the boards are stacked it near impossible to probe anything. But theres always tomorrow!

[@fixitalex]

Don't worry about mistakes David! As my professor used to say "Any experience is experience" Try to check signals around vertical chip with oscilloscope. It maybe over-voltage or problems with driving signal.

[@Ronaldo-eu1nz]

Yo🔥kzbin.info/www/bejne/qJWtapWpg5x9d9k..

[@graealex]

I don't agree. I watched Adrian's video before this video here - and putting in an IC backwards is a typical 8-bit guy type of mistake. It only takes a small amount of time to check for this kind of error.

[@AlexKidd4Fun]

@@graealex What an incredibly cynical and unhelpful comment. It was an accident. If he's not allowed, you aren't. Isn't that an impossible standard to hold? 🤦‍♂️

[@graealex]

@@AlexKidd4Fun There are simply a number of things he will not do, ever - for example, checking the output voltage rails of a PSU before plugging it in, unless the whole Internet is full of people saying that the PSUs are notorious for failing with too-high voltages. There is a good chance that one of the voltages is too high, which grilled the CRT-controller IC in the first place. So he then sends off a board that he couldn't repair because he didn't properly document the orientation of an IC before desoldering it. I can understand it, putting a film into your camera, taking photos, then bringing the film for development, then having to wait a few days until you get the prints takes a lot of time. It's not like tiny devices everyone can carry around and take pictures with for immediate viewing have been invented. They would certainly help in restoration processes. He then gets back the board from Adrian, who showed it to be running very well, and what does he do? He puts it back into his cabinet that probably still supplies too-high voltages to it and watches it die again. That is NOT an accident. That is simply typical negligence.

[@scottparadis6333]

@@graealex This was a human error and a good teaching moment. The 8-bit guy is a geeks geek and he shows us the process he went through. This isnt engineering class.

[@owenrichards1418]

This was a refreshing change from PCs. Thanks for branching out. Also, on the mistake, I've done a small amount of this stuff and it doesn't always go well. Showing that this happens is a good bit of realism. Thanks for keeping it real.

[@Citizen_Se7en]

Forget the haters. Everyone makes mistakes. I like the fact that you're man enough to step up and admit when you make one. Keep up the great work.

[@Dukefazon]

Check the output voltages on the PSU and check the Vcc and other voltages on that part you replaced. My only guess is that the PSU output is too high and it's quickly wearing out that part. I've seen Adrian's video on fixing the part, it was an interesting piece. Yeah, it's crazy, the bigger your audience the more likely it will draw in jerks. You did good, but it's important to take several pictures befure you disassemble stuff so it will help you puting stuff back together. Sometimes you think you'll remember where each screw goes but it's easy to forget little details.

[@piast99]

I had the same idea. The cabinet was designed to run on 100 V ans it is not certain that it was converted.

[@Akotski-ys9rr]

@@piast99 he just assumed that it was actually designed for 120v when maybe it’s not that’s why the transformer is outputting a higher voltage

[@frankcatweazle3611]

When the original PSU was not adapted to 110/120V and is expecting 100 V, the secondery voltages could be to high. Dukefazon is right. Are there any solderpoints at the transformer for different voltages ? Wich Voltages does this arcade game need? You have a schematic diagram, so no problem to look for it. Wish you many success !

[@petesapwell]

I was just going to add the same, Possibly Regulator for main supply is faulty, I watched Adrian Black sort out Daves error and mentioned to him that you need to know what the supply in is and what the regulated output should be, guessing and saying that’s fine will lead to tears. Is there a schematic for this board, PS I’m just about to return 3 faulty monitors to a customer, 2 Electrohome 805-801/2 and a wellls gardener K6100 from Asteroids and tempest

[@Colaholiker]

I wouldn't just check the voltage level (of course that is the first step) but also the possible ripple after rectification (time to get the scope out). Those caps may also be dry and not properly filtering the DC to a level that this IC likes.I am not familiar with the internals of this arcade, but I could imagine that while the actual game runs off 5V, where a separate regulator may be able to filter any ripple away, the CRT board is powered by something around 12V, maybe even unregulated. So really looking at the voltage there may lead to what is causing the problem. When I watched the video and saw you swapping out that SIP IC, I thought "wait.. I have seen this. I need to look back where that was and maybe it helps you too" until you showed the clip from Adrian's video and I realized that it is the exact same boards. 😅

[@robhassell8447]

I have repaired and restored quite a few of these now over in the UK. A few things I picked up from your video: Nichibutsu Moon Base was an official license of Taito Space Invaders Part II. This also means that the 3 stack game boardset and psu are interchangeable with a Taito cocktail machine even though Nichibutsu made their own pcbs, they are exactly the same as the Taito versions. On some of the Nichibutsu/Taito boardsets, they also output RGB on the edge connector and the boardset has an actual colour overlay without using the stick on gels on the tube. This can easily be identified by the two colour proms that are located in the bottom left of the CPU board. If they are populated, then your boardset will also output colour but if not, the proms and 74 series logic chips can be added to do this. Equally, you could also use the B&W or colour monitor/chassis/tube out of a Taito cocktail with minor modification to the connectors.

[@GYTCommnts]

Very interesting info! What is your opinion about what could be the problem here?

[@robhassell8447]

Where the service socket is, there is a switch which flips from two different voltage taps off the transformer. If it’s still set to Japan then the options on the switch could be 100v and 90v AC. The chassis in a lot of these run off around 19v AC. Some have an isolation transformer, some don’t but this voltage will change depending on what the service switch is set to. If I remember correctly there should be taps on the Transformer for an input voltage that is closer to what the US standard is (around 120v AC) if it’s not already set to that, I would change the wires on the transformer to do that. It may not sort the issue out but it wouldn’t do it no harm to be set at the correct input voltage.

[@patzik1910]

I have several si2 pcb’s and was thinking the exact same thing. Just add the color proms and replace the crt with a color crt.

[@GYTCommnts]

@@robhassell8447 Thank you! 🍻

[@m.a.6478]

Oh man, I feel your pain! There are multiple things crossing my mind: - Power supply: does the supply for the burnt out chip do ugly things? Did you already watch it on an oscilloscope? - what about the insulation on the deflection yoke? Maybe you could check if it has broken throgh between the windings. As it is exposed to mechanical stress during the play this could be a problem. You would need to do som HV measurements there and also measure the impedance of the yoke The easiest way to deal with it would probably be to replace the board and the yoke with a vudeo unit from a different similar machine. But finding one.... hmm... difficult.

[@Coffeeology]

Dave. THANK YOU for showing the mistakes. I'm new to electronics, and it's all bewildering. I honestly take a lot of comfort with the fact, that the people I look up to in this world, You, Adrian, Perry from Retro make mistakes, and own up to them.

[@idormain]

Personally, I think showing your mistakes is a sign of honesty and integrity. Getting it out there is a way people learn. Good on you for keeping your mistake in the video. Anyone who is critical of you for making a mistake simply isn’t grounded in reality. Great video, love your work!

[@datapoint6859]

Yet he still has not corrected the literally lethal video of him shorting out the AC lines on the IBM video, to a point where he turned comments off so that new viewers could not see the warnings from people who actually know what they are doing. We're not critical of his mistake, we're critical of his hubris.

[@MrJef06]

@@datapoint6859 interesting. Link?

[@datapoint6859]

@@MrJef06 Video Wh2OCBZpzZ8, starting at 4:15. Google around on the video title for more info about what was wrong with it.

[@MrJef06]

@@datapoint6859 thanks

[@michaelhorne8366]

@@datapoint6859 My favourite is how a guy who has been doing this for.. however long he has been doing it, does not have a torx kit, meaning he needed to use a rotary tool to cut a slot into the screws instead of, ya know, treating the machine with some kind of respect and purchasing a kit from his nearest hardware store. There were a few peeps on twitter that publicly stated they would never loan him hardware for videos again after that cluster. A great lesson indeed.

[@dustinsmous5413]

It's almost definitely a voltage issue from the power supply. I worked on vintage arcade machines for quite a few years, and with these issues, it tends to be an issue with the power supply for the cabinet or the power supply section of the monitor, and there's a small change it could even be the horizontal drive transistor next to the CRT flyback transformer causing voltage issues damaging the vertical drive IC. I know that was an issue on one of the upright space invaders systems I worked on before. If you could make the schematics available for both, I may be able to give you some ideas of where to look next. As for the joystick, an appropriately sized nylon washer under the nut should fix the issues with it being loose...

[@GoSlash27]

That would be my suspicion as well. You need to go over the power supply with an o-scope and make sure the voltages are all within spec and well regulated.

[@Spacemutiny]

As someone who is not technically minded I just wanted to say I really enjoy watching your videos! They’re really a fun watch even if you don’t fully understand the intricacies.

[@royconway8700]

As a guitar amp tech/ amp builder and guitar tech, I came here to praise your for your honesty and the frustrations we face in tracking down unknown issues. I feel you brother

[@Hidyman]

20:03 I believe there is a rubber bushing inside where the shaft comes through. You could probably find a silicone (or rubber but it would be less durable) hose of the proper diameter to replace the bushing to firm it up. There also would most likely be a washer at the end. You could check the stick on the other side to see if that is the case. At worst you could use an angled rubber washer that would commonly be used in an old school water valve (backed by a small fender washer or two.)

[@jtherrie]

This was my first thought too. As soon as he said the bolt was tight, but the stick was still loose suggests that there was some type of bushing in there as a wear component. Given the fact that there isn't much evidence of it left, I am guessing it was rubber that dry rotted and just disintegrated over time. Really at the end of the day it doesn't matter what the material is, you are just looking for something to fill the void between the 2 parts. You might even be able to be able to use a brass bushing, which in a pinch you can always use a dremel or hack saw on to make it the right length.

[@BixbyConsequence]

@@jtherrie I'd 2nd a brass bushing. Or if a correct size can't be found, just use enough wraps of thin brass foil to take up the slack, and apply a bit of heavy oil or grease.

[@TheNexusChan]

There is. Overtime the metal rack could've shaved down as well.

[@robertzieg3893]

I have run in to a similar issue previously with a joy stick. I ordered a multi sized set of stiff rubber O rings from amazon and it had one that fit perfectly. It made my joystick very stiff.

[@geovani60624]

20:01 I believe you could add some washers to it, I'm sure it had play because of the tolerances and supposed to have washers but the previous technician forgot to put it back in or lost it

[@jonnyfatboy7563]

na just a little ptfe tape round the shaft should service

[@geovani60624]

@@jonnyfatboy7563 that would work, but I believe it would get loose over time

[@jonnyfatboy7563]

@@geovani60624 a possibility but none the less a solid fix.. or measure and lathe the correct diameter part necessary. I opt for the first 👍

[@Octojen]

I could have had a rubber washer, which has since failed - there seemed to be dark discoloration around the nut.

[@jonnyfatboy7563]

@@Octojen the nut with some spacer would be for in and out of said joystick but you can clearly see the stick itself is like throwing a sausage down an alleyway 😊

[@TKEnvironments]

Man, you are a hero, been following your channel for years and this is one of my favorite videos so far. Love your content, keep it up!

[@patrickcarrillo714]

10:19 oh how far you have come since the iBookGuy days when it comes to your soldering equipment Awesome soldering iron, suckers and a desoldering gun Man All those nice tools must make soldering SO MUCH easier and a much more pleasurable experience I'm guessing

[@TalynWuff]

Don't heed the armchair warriors. You're only human, mistakes are how we learn. The haters just want something to complain about or point out so they can feel superior about themselves in the absence of any other notable qualities. lol. Much appreciate the teardown and repair videos, it's fascinating seeing old toys of the era taken apart and worked on.

[@jase_allen]

I forget who said it, but one of my favorite quotes is "An expert is a man who has made all the mistakes which can be made, in a narrow field."

[@Jezee213]

Agreed!

[@jumbledfox2098]

Love your pfp!

[@cyberwomble7524]

Or they're older people drawn to this channel because of its content, and probably have decades of practical experience behind them. He can't have it both ways - someone points out he's made a mistake, he then says he will learn from it, but blames the person for telling him in the first place... If the only comments he wants are of glowing praise, well... toadying being regarded more highly than honesty, that's a slippery path - may end up President.

[@therealswarvey]

@@cyberwomble7524 like seeing him short live and neutral on the power supply for a monitor on an antique system, then wondering what he did wrong. That was terrible and not what I expected from a channel with this kind of content.

[@DerekLippold]

I appreciate seeing and hearing about any mistakes - its honest and educational and it covers the whole process without cutting too much just to make it look nicer - which makes a difference.

[@Lamster66]

I just put 3 sugars in my coffee instead of 2. You Asked!

[@CF542]

These restorations are fantastic to watch, thank you for all of the efforts to get this done. I am certain that someone watching will have the answer to help out on this. Probably someone who used to repair these and knows its quirks to get them running again.

[@mgjk]

I so much appreciate the honesty and humility in approaching problem solving. Even owning up to not knowing and seeking outside help, even when that outside help solved it "too easily". This is so refreshing and uncommon in technology.

[@tony4624]

I've learned from watching Techmoan - Japanese runs 100v and 50hz in one area, but 60hz in another. Seeing the 100v 50hz/60hz on the label made me think of it being made for the Japanese market right away.

[@Okurka.]

The Japanese text didn't give it away?

[@UberAlphaSirus]

@@Okurka. And Made in Japan.

[@spaceflight1019]

If you look at the transformer, there are a multitude of taps for different voltages. Japanese ham radio equipment manufacturers have been doing this for years now.

[@mhammadalloush5104]

@@Okurka. most would mistake japanese text for chinese due to the common writing system and sometimes the same phrase or word could look the same between the two languages further adding confusion for those who don't speak either language.

[@NoshAbroad]

@@mhammadalloush5104 except it said "Made in Japan" in English so one word more likely assume the text was Japanese. Plus the first two kanji / hanzi were 日本 (Japan)

[@MrStillions]

Mistakes are so much easier to see from a distance. When you have been staring at a problem so close and working on it for so long its easy to miss things, even things you would normally spot. The amount of work you have put into this is really cool to see and I am sure you will find a great solution and have it working 100% again in no time! :)

[@christophergorge]

watching the video from adrian's digital basement, he mentioned that david was doing the replacement of the chip in front of his brother who mentioned that he's putting it the wrong way. well now we know his brother was right all along.😀

[@waynenewark5363]

Colleagues and I have found that sometimes describing a problem to someone can help you to identify the issue without any input from them.

[@tyleranderson4721]

This is one of my favorite videos of your recent offerings. Fantastic!

[@tyleranderson4721]

Also, you should have changed out the coin box for a drink holder. :)

[@ondrastepnic]

I just love the Petscii Robots OST in the background. Great video anyway! It shows we all make mistakes, we are not perfect.

[@Yous0147]

Your mistake and you addressing it actually gave me some needed hope. I've had a couple of mistakes working on my own small projects too and seeing you and others stumbling on them yet keeping on trucking gives me much needed relief and understanding. So thank you for that, I appreciate it.

[@highpath4776]

It did by then need the second pair of eyes. Though given it sort of worked, then didnt , would be indicative of the last thing you did was wrong, but I can understand that having had the item apart and back together so much with frustrating results it can wear you down (mentally !)

[@davidlord5739]

I would check the deflection yoke. Over time they can develop shorted windings which would give lower impedance and require you to turn up the horiz and vert drives to compensate for smaller magnetic deflection fields. Another alternative could be a bad fly-back transformer, but it usually takes out the horizontal output transistor if it goes bad. You should center the pots. before retrying it and see what it looks like. Most trim pots are designed to be in the mid position or near it. You should also check every regulated power supply voltage. Could you post a schematic of the machine?

[@erichenriksson7631]

Great video and a wonderful channel! I absolutely love watching your process - be it successful or not - rather than just a pre-scripted, TV chef pre-prepared, how-to video.

[@Paul4350]

I love your dedication to doing the "Repairs", yes so much is learnt from making a mistake or a fail but keep on trying. So glad to see "Old" Tecs still doing what I did for years. I find it very interesting that it still had the service manual with it as most are long gone. Could be worth scanning and posting it on line. Thank for the effort and the video. Now to watch part two.

[@dgcurtis5114]

For the rust on the chromed leg: 0000 grade steel wool will clean the surface rust off without dulling the shine of the chrome. In fact, it should make the whole leg assembly look better.

[@serraramayfield9230]

Get Brasso with that as well, and perhaps attach it to a drill.

[@Kangsteri]

Aluminium / aluminum foil works too. It's more gentle. But the rust will always come back after time..

[@nameofthegame9664]

Autosol is in my experience the best way to clean and polish chrome

[@Zerinsakech]

Metal polish might also do the trick for the rust.

[@thomashughesgermany6241]

CocaCola and aluminum foil has worked for me every time.

[@StickyandBaldi]

the process of troubleshooting and learning is the value here! Really enjoyed this video. As much as I enjoy seeing success stories, I really enjoy the times where there is an issue and then there is the problem solving to get it resolved. Thanks again!

[@3DJapan]

6:14 This is the problem I had when building my first PC, researching whether all of the components would work with that motherboard.

[@Sky.Dog757]

Absolutely love your videos! Your one of my favourite retro tech channels next to LGR. Your videos are educational and really fun to learn old tech. You’ve inspired me to start collecting old tech I’m only 23 but just wanted to say thank you for the awesome / wholesome content! - Joseph V.

[@FightingForceSoulless]

4:55 can I just say that I absolutely LOVE this track from Petscii Robots?

[@dinosaursneverexisted8985]

I'm glad you've decided to keep making restoration videos, they're my favorite of your content, although I like everything you do! The video you did where you talked about how 8-bit graphics worked is what hooked me to your channel 7 years ago!

[@SMG74_the_engie_main]

We boutta have an 8-bit guy arcade!

[@burrfoottopknot]

I love watching the mistakes, in gameplay videos or tutorials about hardware - Showing the audience is the best thing to do. Great stuff ty

[@apislapis]

I was taught that 'every mistake is a learning opportunity'. I have more respect for 'tubers who include their mistakes, rather than edit them out simply to look good. You're M.O. is the correct one imho, David. You do everyone a good service this way. Ignore them, 'empty vessels make the most noise'. Many thanks 8-bit Guy, can't wait for part two.

[@raven4k998]

yeah he shows the entire process of fixing it and learning from his mistakes if he made non I would call bs on his fix cause how the hell does he get it right the first time everytime

[@Otakunopodcast]

You might want to hit up fellow KZbinr "Joe's Classic Video Games." They repair a TON of video games and would probably be able to help (or at least point you in the right direction.) Also, please don't let the haters get to you. I think videos where the person edited out (or simply didn't include) their mistakes/missteps do a disservice to the community, because they give an unrealistic expectation to people watching that "oh, this stuff is a piece of cake" when in many cases it's the exact opposite.

[@ikonix360]

Can't tell you how many mistakes I've made over the years working on electronics. Sometimes even when marking a part as to the orientation one can be tired or in a hurry or distracted and oops the part is installed wrong.

[@EightPieceBox]

Seconded! Joe's channel is cool. I just wish his videos were shorter sometimes.

[@andrewbrown3304]

"Masters have failed more times than beginners have tried". You're a master.

[@dbdors]

Love these repair videos, you do great, it’s interesting to see the processes you follow.

[@toxictrumptube7763]

This is exactly the kind of content why I watch so much more KZbin than television…

[@haweater1555]

I have Satellite TV with the full premium package (family plan shared subscription). LNB failed early in the summer. Took me a month to getting around to order a replacement. Now it's working.. But I haven't turned my TV on for weeks because KZbin has better content completely on-demand at my fingertips.

[@cpayne8177]

I used to repair a lot of different electronics in my early career. The mistakes happen to everyone. Good for you for sticking with it.

[@ScrambledAndBenedict]

I probably shouldn't laugh at it, but the thought of you getting "totally roasted" by the comments every time you make a minor mistake really did make me laugh hahaha

[@TheWarmotor]

Oh man, the ladder diagrams in that manual... nostalgia overload.

[@dynabeen2]

That "moon" on the cabinet is really the Comet Empire (Gatlantis is the Japanese name) from Space Battleship Yamato. So I am guessing this was some kind of Space Battleship Yamato themed game in Japan. Thanks for sharing the "failure", it is great to see you sharing the problems as well as the successes.

[@rodneyabrett]

Damn, good eye! I knew that image was very familiar to me but I could not quite place it. Thanks!

[@CluelessDad]

ah, i just wrote the same comment. yeah, either licensed or just a 'sampling' of the artwork...

[@HowManyHintsDoYouNeed]

@@CluelessDad considering this model is "similar" to the Space Invaders one... Yeah totally lol

[@notbaldfrost]

Nichibutsu was a bootlegging company (among the first as far as video games are concerned). They stole all their art, even on their handful of games such as this one which were legitimately licensed clones. The poster for this very game had Darth Vader on it.

[@Mr_Top_Hat_Jones]

It’s definitely a bummer when the problem returns 10 minutes after you thought everything was good. However, if that means we get a part 2 to the video, I’ll take it. Great video, as always!

[@1xsandrax1]

I like it when you show the mistake because it helps me learn as well! Being in the IT field, I always like to keep on learning, and of course, I've had my own mistakes. Your channel has helped me so much with doing repairs in my line of work. These videos are fantastic, and I always enjoy watching your channel! 😊

[@markmaisy4858]

I commend you for your tenacity on this project. I spent my youth playing these and think its important to keep them alive. When you look at the volume of components in these cabinets it demonstrates how the gaming industry started. The youth of today don't seem to appreciate tech and take it for granted with their mobile phones!

[@smeep2k4]

I, for one, enjoy it when the mistakes are left in and explained, so we can all learn from it. I'm not sure why anyone would roast you for this. We're all human, and we all make mistakes. I hate that the internet has basically turned into a pack of hyenas. Anyway, keep up the good work, David!

[@cheezitupp]

Love this and always love when you show the process- don’t let the comments get to you, your channel got this far for a reason. Keep it up

[@Tabletop_Epics]

The greatest failure is in not learning lessons from our failures. Thank you for honestly sharing your process, and to heck with anyone who doesn't grock the ups and downs of experimentation and learning.

[@EinKerl3554]

Many of us learn from your mistakes. I have no doubt your willingness to share them have helped save many old machines. Thank you.

[@KristianWontroba]

I highly recommend that you try liquid Bar Keeper’s Friend (in the gold-colored plastic bottle) to clean the oxidation off of the chrome parts of the cabinet like the legs and feet. I used that stuff to clean oxidation from chrome parts on an old drum kit, and the results were completely amazing. Good luck on this restoration! Love your videos!

[@randymagnum6680]

Good call, that stuff is magic.

[@srenhaandbk7904]

Wow, when I read the "gone wrong", I feared it might be the same story as when he fried that IBM (clone?), and people went apeshit over it. Would have been a much greater shame if it was a 70's arcade cabinet. Glad to see this, great work!

[@maclura]

i believe it was some sorta prototype which is why people were annoyed, anyways i think someone else fixed that machine.

[@tjnucnuc]

Lol can you tell me when that video was? I didn’t hear about that.

[@tjnucnuc]

Ok update found it. Didn’t know he was some creepy gun nut too. Is he touched or what?

[@adamscheuring6940]

What a stupid saga that was. No one gave two sh*ts about that IBM until he made a video on it.

[@dbowl7111]

@@adamscheuring6940 yeah because they were extremely rare, and the one time someone found one, he took a Dremel to it and fried it

[@ronostrenski8359]

Thank you for your honesty. All technicians, if you do enough repairs will occasionally put something in backwards. It’s good to see these mistakes to remind us to double check when replacing components.

[@BaconFire]

David, no need to apologize for mistakes. Its how we learn in life from those mistakes. You dont ever have to explain yourself. These videos you make are why most of us come here. I totally LOVE this content when you restore and fix old cool tech. It really is a joy to see these videos and we look forward to your future vids. :)

[@shanehebert396]

Yeah... My first x86 machine was an 80386-40. I decided to put an 80387 into it and bought one. I was being really careful and making sure to plug it into the socket correctly and everything (PGA) yet somehow between the last time I put it on the socket to check the orientation and the time I inserted it into the socket, I had rotated it 90 degrees. I plugged it in and powered the machine up. Oddly, it took like 15 seconds to get to the BIOS screen (a really long time) but then I didn't see the 80387 present. So I powered it off and back on and it came up just as fast as it should have but still no 80387. I did the first test (lick my finger and touch the top of the chip to see how hot it was) and it was really, really hot. I instantly realized something was wrong and looked at it carefully to see that I had rotated it the 90 degrees somehow and destroyed it. I was bummed and the money to get the chip was a lot for me at the time, being a college student on a very limited budget. But... instead of trying to send it back to try to claim it was received not working, I took my lumps and saved up and got another one... this time being even more careful. This one went fine and I was able to enjoy the speedup of having the FPU. So yeah... painful and a learning process that taught me a lesson that I remember to this day.

[@bryguy062485]

@@rogerdahl0 Yup, you are correct! Shane even mentioned it was a PGA in his post haha. No shade meant for you first Roger (Since you are both Roger!), we all are guilty of overlooking words sometimes when reading. God knows I'm guilty of it all the damn time!

[@spaceflight1019]

Yoda doesn't tell Luke that failures are expensive. We learned that the hard way.

[@EightPieceBox]

Ooh that sounds painful! I never bought a math coprocessor because of the cost.

[@shanehebert396]

@@EightPieceBox I had bought the 386 after the 486s had come out so the FPUs were cheaper then. I didn't get an actual Intel one, I believe it was a Cyrix one. IIRC, it had matrix operations as well that one or two programs I had could actually use. In any case, at the time, I remember it being something like $150 but I was on a tight budget at the time and having to buy another one was painful.

[@Oddman1980]

If that chip was powered up while being installed backwards, it could have been damaged. I don't know what those chips cost, but if they're cheap enough try another one, now that you know which way it goes.

[@fgaviator]

See Adrian's video. He had a second chip. Adrian replaced it with the fresh/unused chip. He didin't even bother to check the chip which was powered backwards. He assumed, it had no chance of surviving the ordeal anyway.

[@Oddman1980]

@@fgaviator Well that will teach me to spout off suggestions without complete information.... maybe.

[@FrankBitterlich]

By showing your mistakes, you're enabling *others* to learn from it, too. And that's something I want to say "thank you" for.

[@danielsass4134]

I've been watching your videos for about a year now. They're very good. You only upload a new video every few months, but they're all of exceptional quality. My favorites were the history videos on Commodore.

[@srtech2205]

You need to replace all of that IC's supporting components, also look into that "100v" volt thing from the beginning, and check the PSU and output voltage! You know when PSUs get old they overvolt!

[@daemonspudguy]

PANIC!! The 8-Bit Guy DID SOMETHING WRONG! THIS IS THE IBM INCIDENT ALL OVER AGAIN! PANIC!!!!! Right, got that out of my system. I am happy that videos that include failures are still released, as it's a good learning experience for all of us.

[@garyv2498]

I came across this video two or three weeks ago and had it loaded up on a tab in my browser. Few weeks go by, a couple of restarts and cleanups of open tabs and I kept this one each time because I really wanted to watch it. (just not then) So I finally get around to it this evening and I'm glad I kept it. This kind of thing really interests me and restoration of an old game is something I really want to try someday. Not going to roast you for your mistake because a) who hasn't done something like that? b) it added to the drama of the video, and c) It was a little amusing when we learn it was only in backwards. Really hope you post a follow up. I'm subscribing (can't believe I wasn't already) so I can keep an eye out for it. Love a many of your other videos too. Keep up the good work.

[@TheDreadGazeebo]

They call him the 8-Bit Guy because anything he touches ends up in at least 8 different bits.

[@M1LAD81]

Sanyo board at 6:58 I enjoyed this episode thanks, David!

[@gregclare]

It would have been interesting to test those old capacitors, before they got binned. Rubycon capacitors of the time were pretty good quality. It wouldn’t perhaps be surprising if some of these old Rubycon capacitors, measured better than their smaller modern replacements.

[@nicolasjonasson4820]

I would be very surprised if that was the case, comparing to similar types. Sooner or later - leakage galore, its just how things go

[@dantemalus6533]

hi greg, i think its nice to run a device on old components as mutch as possible. but its mutch safer to replace them down the road. they are around 40 years old after all. i would do the same as david. but im relativly new to vintage electronics.

[@dantemalus6533]

sorry i read your text wrong. yes it would be interesting just to test them! XD

[@Aliens2Exist]

my brother in christ they were exploded

[@gregclare]

@@dantemalus6533 Yes, my comment was prompted by my own experiences with capacitors in old CRT monitors of the same time period. Specifically, I have seen 40yo Rubycon capacitors that are still well within spec, and with lower ESR than new replacements. It has made me less prone to just automatically replacing all old electrolytic capacitors. i.e. Some older, quality capacitors, may still have more life in them than some modern cheaply manufactured replacements. Hence, why testing old removed capacitors (and their replacements), is always an interesting exercise.

[@JPdelaGhetto]

Absolutely love your videos like this. The way you go so deep on every single little thing you try to fix and how to trouble shoot helps us newbs out tons. Frankly if you didn't record and show off the mistakes you see I wouldn't understand a lot of the mistakes I make. During the pandemic to keep my mind occupied I started finding old broken consoles and learned how to solder so I could start fixing them. Now I got a giant library of hardware and a lot of it is thanks to watching your videos for reference. The only roasting I'm scared of is you getting roasted by playing with that CRT while it's on. I always keep getting told that's a huge safety no no. Yet I watch you just jump in there like it's nothing 🙂

[@MagicPlants]

Great job and thanks for sharing the entire process. I have been tripped up by those notches and pin 1 too, so thank you for showing us all the process.

[@jasonfabrick9308]

That cleaned up very nice. It would have been nice if the "Free Play" button could have been installed without drilling a hole but it is your system.

[@gavinthomas214]

Great video, as a guy who grew up around early arcade machines I find this type of content fascinating. Thanks for all the hard work, I hope you find a solution to the rolling screen issue.

[@skycron]

"And here are the old caps. Let's have moment of silence while we thank you for your decades of service" [*Unceremoniously dumps into garbage*] The timing made me laugh out loud. Big fan of David's work and a longtime subscriber to the channel. That just hit me from the side though.

[@user-gh5hi6fb4t]

David - I am very inspired that you always admit your mistakes and show it on video. You are a great guy! I well understand your frustration. I think every person who has been fiddling with old computers a lot should know this feeling well. Well done for not abandoning this project! Thank you for the video!

[@Datan0de]

I watch videos like this MOSTLY to learn from the mistakes! It's a joy to watch a machine like this slowly come back to life, but the real lessons are in the hiccups and missteps along the way. As someone who owns an arcade cab but has very little experience doing maintenance beyond replacing a handful of components, videos like this are gold.

[@Toby-Wan-Kenobi]

I love how relatively simple old tech is. Easy to see each individual part and easier to fix.

[@volvo09]

it looks easier to fix, but in circuits like driving a CRT it's all very finicky. the older you get, the more the picky it gets. CRT's rely on tuned circuits oscillating in time (like pushing a kid on a swing) and when that oscillation time is wrong it can be hard to detect where the fault is. it can be somewhere down a chain of "swings". but you are correct, at least the parts are easy to change.

[@theopenrift]

I couldn't help but wince at the addition of the free-play button, I feel like inserting coins really is a core part of the experience when it comes to oldschool cabinets like this. The mechanical clinking as it falls into the coin tray, the speakers making a noise in acknowledgement, it's always a nice feeling that you just can't get with a simple button.

[@pibyte]

Kudos for the endurance on this project! And its amazing you share your mistakes for us to learn from it! Thats the way to go.

[@AJMansfield1]

The difficulties with probing the board in-situ can be resolved by getting the appropriate probing tools -- some good hook-style probes will let you get in there with very little issue, or a set of mini-grabbers. And if not, you can always just go with the universal probing solution: temporarily soldering in some thin wires. But, if you're getting the same problem again, it's because the same chip broke. If the chip broke, it's because its inputs exceeded the specifications you can find on the datasheet -- and if I had to guess, it's that the power supply voltage is too high. Regardless though, that means the circuit generating that input is defective, so you can trace back and find e.g. the voltage regulator that's failing to regulate the voltage down correctly, verify that its own input is still within specifications for what that regulator _should_ tolerate, and if so just replace that regulator.

[@michaell8749]

i was thinking the same. someone above mentioned using an iso transformer. maybe that could help with the voltage problem i think he is most def having.

[@mattlastnamehere6403]

plus if the IC was in backwards, it very well could have caused damage.

[@absalomdraconis]

​@@michaell8749 : I doubt that an isolation transformer is going to help.

[@absalomdraconis]

​@@mattlastnamehere6403 : Damage could have been caused, but the duplication of the previous error renders that unimportant- the duplication of the problem indicates a more fundamental issue elsewhere, which in turn means the cause of that problem needs to be fixed.

[@dariocarrascomartinez5506]

I mean, the badge showed that the power supply is supposedly designed for 100VAC 50/60Hz

[@evifnoskcaj]

Also, this title is a misnomer: so many things have gone wonderfully right with this repair and it's so close to being better than new (especially the capacitors)! You got this! Check for ghost input, some sort of signal degradation or interference, and trust your instincts (use the force!)...seriously!

[@thepeternetwork]

You really do remind me of my late uncle and his ability to figure out how things work. Coincidentally, I'm running into a similar problem. The other day, I gave my Colecovision a test run, and in the middle of gameplay, the screen went black. I could hear the game audio going, but the video was completely out. I tried replacing the RF cable with a digital coaxial audio cable from Best Buy, that didn't work. I tried hooking the RF cable to an old fashioned switch box like what normally comes with old consoles like the Atari and such, that didn't work. I had already had it plugged directly into the TV with an RF to coax adapter, and that didn't work. People on a Facebook group recommended I check the capacitors or the power supply. I'm stupid when it comes to futzing around with ancient electronics, but I'm sure my uncle would have known what to do if he were alive and still with us. And might I say how lucky you are to be able to acquire, much less work on, full-sized arcade cabinets in your home while my already-crowded apartment must settle for emulation on computers and game compilations on consoles.

[@prestonostra]

Fantastic video! I love watching you fix stuff...its like magic to me.

[@freddaniali]

David, sometimes the NEC and NTE MOSFETs have their pins revered like that as well and I have made the same error as you have in the past. It was an honest mistake to assume that the flat side and written sides were identical on both parts.

[@highpath4776]

they presumably do that to avoid a copyright ?! infringment

[@freddaniali]

@@highpath4776 No, they are just lame.

[@ballyastrocade5672]

@@highpath4776 There's no copyright on that sort of thing, no. It's just a matter of how they decided to do their plastic molds. Some companies did it differently than others because they already had the molding machines set up to make them a certain way for other parts.

[@ballyastrocade5672]

Technically, the pins weren't reversed -- if you look at the part where the guy is holding them side-by-side with the markings face-up on both, the original part has the pin-1 stripe on the left, and the replacement part has the beveled edge (also pin 1) on the left as well. So both parts have the same orientation and pin 1 in the same spot -- what happened was that David was going by (faulty) memory as to which way the markings on the chip were facing when he took the original part out, instead of orienting it according to the silkscreen on the PCB.

[@highpath4776]

@@ballyastrocade5672 But that looks like the flat part mounted to the heatsink was as David took out, so indeed 'reversed' between the two part numbers if the bolt mount is offset