2021 C64 Repair-a-thon #1: "It stumped me!"

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Adrian's Digital Basement

Adrian's Digital Basement

Күн бұрын

Пікірлер: 361
@danielmantione
@danielmantione 3 жыл бұрын
The Dead Test does a very limited RAM test, because the C64 is in Ultimax mode. In Ultimax mode only 4KB of the C64's RAM is available and this is what the Dead Test tests. (This is documented.) The Diagnostics Cart does a full RAM test. Therefore don't assume all of the RAM is good if the Dead Test passes.
@mal2ksc
@mal2ksc 3 жыл бұрын
I recall the IBM PC diagnostics only testing the first 256 KB because that's all the original 5150 shipped with, and that could cause similar issues, especially because anything above that would be in another bank or even on an expansion card and thus could not be assumed to be good just because the machine boots or passes basic diagnostics.
@XLV750RD01
@XLV750RD01 3 жыл бұрын
Even if only the first 4kB were tested, the test would come back negative because of the faulty D0 bit. Your comment makes no sense.
@danielmantione
@danielmantione 3 жыл бұрын
@@XLV750RD01 With D0 bit fully faulty, the dead test would flash the screen rather than boot up with the tests. So the D0 RAM chip was partially working for sure, the fault was in memory cells with higher addresses.
@XLV750RD01
@XLV750RD01 3 жыл бұрын
@@danielmantione Do you even understand how the binary system works ?
@danielmantione
@danielmantione 3 жыл бұрын
@@XLV750RD01 Dude, I know the C64 from left to right and top to bottom. Carefully read again what I write, it is exactly what was going on in that machine.
@flow221
@flow221 3 жыл бұрын
Dead Test: The Betrayal. If nothing else, it's a good action movie title.
@Fuzy2K
@Fuzy2K 3 жыл бұрын
Why did "Written by Michael Bay" pop into my head?
@ericvenneker
@ericvenneker 3 жыл бұрын
@16:30 gracefully de-soldering the shield, and immediately tosses it to annoy the shield lovers. I love it.
@youdontneedtoseehisidentif4939
@youdontneedtoseehisidentif4939 3 жыл бұрын
Y'know, I would've thought he'd learnt his lesson after his troubles with the Macintosh Colour Classic… ;)
@awilliams1701
@awilliams1701 3 жыл бұрын
I don't get why people love that trash. It doesn't do anything. It's not even like it makes a heat sync.
@SpearM3064
@SpearM3064 3 жыл бұрын
@@awilliams1701 My guess is that it's about originality. In the 1980s, the RF shield was required to bring emissions down to FCC standards. Of course, it's no longer required, but it's an original part.
@awilliams1701
@awilliams1701 3 жыл бұрын
@@SpearM3064 Well yeah that's why it's there, but it's not required anymore and the FCC doesn't give a crap about these machines. So the question isn't why is/was it there. The question is why do people care about it going into the trash can where it belongs?
@ericvenneker
@ericvenneker 3 жыл бұрын
@@SpearM3064 I am not an C64 enthusiast nor capable of fixing them and I understand the originality sentiment. That said: Adrian at least tries to revive these machine's while others don't give a toss (pun intended).
@VVerVVurm
@VVerVVurm 3 жыл бұрын
I noticed a pattern: it is always the last chip you swap that fixes the issue. Why don't you just start with the last one? It would save you some time ;P
@catriona_drummond
@catriona_drummond 3 жыл бұрын
Brilliant! :D
@brentboswell1294
@brentboswell1294 3 жыл бұрын
It would make his videos too short...😝
@VVerVVurm
@VVerVVurm 3 жыл бұрын
@@brentboswell1294 yes .. scratch my idea .. the longer videos the better :)
@hjalfi
@hjalfi 3 жыл бұрын
I've always said that one day, when looking for something, I'm not going to stop looking when I find it, just so I can say it wasn't in the last place I looked.
@brentboswell1294
@brentboswell1294 3 жыл бұрын
@@hjalfi U2 has a song about that..."I Still Haven't Found What I'm Looking For"
@bobhope1160
@bobhope1160 3 жыл бұрын
Its crazy how much content I keep discovering. Legit I've been binge watching your channel for months now
@jarrettrodriguez5341
@jarrettrodriguez5341 3 жыл бұрын
Thanks fir bring us on this journey today. It was great to feel like we were there at the bench with you!
@misterkite
@misterkite 3 жыл бұрын
Here's a tip for testing the 74LS chips. If you have a TL866-PlusII eeprom programmer and use the Xgpro software, under Device->Logic IC Test there's a logic tester that can not only detect the IC, but verify that all the pins are working properly.
@retrolabo
@retrolabo 3 жыл бұрын
I have seen Adrian using that before, I wonder why he didn't use it that time :)
@VVerVVurm
@VVerVVurm 3 жыл бұрын
@@retrolabo he needs to keep himself a handicap so his powers would not frighten us
@neilbradley
@neilbradley 3 жыл бұрын
The risk is that those chips can be marginal - test just fine in the TL866 but don't in circuit. Same with DRAMs. Had that happen WAY too many times to trust chip testers.
@Calphool222
@Calphool222 3 жыл бұрын
@@neilbradley Yeah that stupid tester in the TL866 is flaky. I've had it lie to me several times. I think it might be due to the fact that it's not really using the chip in the same way that the motherboard is. In other words, it's maybe flipping the CE and doing a few tests, and that's it, whereas that CE line might be left on in circuit, and the chip might get warm over time and have a thermal issue because of that.
@neilbradley
@neilbradley 3 жыл бұрын
@@Calphool222 Yes, exactly. Each system that uses the chip will have different loading and timing characteristics - something the TL866 (I assume) does not.
@thatonebelgian
@thatonebelgian 4 ай бұрын
I have been binging your videos for like 2 months now and I have gotten to the point that I just felt it in my lil toe that it was a RAM problem. Man
@danieltufvesson1349
@danieltufvesson1349 3 жыл бұрын
Just a quick tip since you have the wonderful HP 547A current tracer. I have luck with it sometimes detecting bad RAM without any de-soldering or test programs. If all RAM chips are the same type/manufacturer/batch, you can use the 547A to "feel" the center of each RAM chip, setting the sensitivity so that it juuust lights up and compare the chips back and forth. It takes little while to get the feel for it, but if one chip makes the 547A light up easier than the others it is often bad (as in more over all current flowing through it). I've found this method to be more reliable than trying to compare chip temperatures by hand. Other chips can sometimes be detected in a similar way. Love your videos. Keep up the good work.
@martijnthie3087
@martijnthie3087 3 жыл бұрын
Thanks for picking up the Commodores again! I know that you've done these videos already, but... I really love them! You can't have enough of these.
@theimitanturproject8310
@theimitanturproject8310 3 жыл бұрын
Very engaging video. I was at the edge of my seat every time the C-64 was booting to see if the replaced chip was the right one. :)
@taltechchip5827
@taltechchip5827 3 жыл бұрын
I'm very happy to see this C64 marathon :) Thank you!
@uomoartificiale
@uomoartificiale 3 жыл бұрын
"would you look at that!" Ah the sweet endorphins release everytime I hear those words after a 40 minutes troubleshooting video! Nothing beats that.
@idj20
@idj20 3 жыл бұрын
I got totally engrossed in this video, it's far more interesting and stimulating than Saturday Freeview TV here at the UK.
@chri-k
@chri-k 3 жыл бұрын
Not related, but; Was that rickroll monitor at the back always there???? ( 28:20 )
@bodolevente2246
@bodolevente2246 3 жыл бұрын
@@chri-k It's been there for a long time but it's always changing i.e sometimes it's a rickroll, other times it's just a clock, etc.
@FHolloran
@FHolloran 3 жыл бұрын
Heck yeah repairathon! Pretty soon I’ll be able to have a repairathonathon.
@melissa.merritt
@melissa.merritt 3 жыл бұрын
My desoldering gun gets blocked just the same as yours, what I do to reduce the blockages is when I suck the solder off the components I continue to hold the trigger On for same time after and sometimes pointing the nozzle upwards with the trigger On, this gives it time to clear the gun,,, keep up the good work 👍
@museum1401
@museum1401 3 жыл бұрын
Congrats on 100K Adrian! This channel has really helped me through these strange times. 🙌
@jonathancombe9991
@jonathancombe9991 3 жыл бұрын
One thought I had when you were checking the outputs from that chip where the signal from 2 of the pins looked odd - compare it with the output from the known working Zif c64. If they are the same on that one, then that could be ruled out as the problem.
@MrGtagangster
@MrGtagangster 3 жыл бұрын
Aaaaaaaaaah, a great video to watch with a cup of coffee after dinner with a cookie. 41 minutes of entertainment and fun. Love to see another repairathon!
@jimhewes7507
@jimhewes7507 2 жыл бұрын
Fun video! A couple days ago I watched this video as the first Adrian's Digital Basement video I've seen. I was surprised to see there was such an inexpensive scope, not that I keep up with these things. I bought a C64 new in 1984 and when it stopped working in the early 90's I just boxed it up and bought a C128D to replace it. After watching this I got a little excited and started thinking Hey I could buy this little scope and break out the old C64 and see if I can fix it. But now after watching the repair-a-thon videos 1 thru 3 I realize it takes a lot more. Adrian repairs these C64's mostly by narrowing down which chip is likely bad and then swaps chips to find the bad ones. So you really need to have these extra chips on hand not to mention the sockets, dead test cartridge, and soldering and desoldering iron. And if the PLA is bad another video suggests it might cost about another 60 bucks to manufacture a substitute for that. So all-in-all not really worth it just to try to fix a single C64 unfortunately. :(
@ChrisFaulkner
@ChrisFaulkner 3 жыл бұрын
thank you for doing this video. this is an excellent video for troubleshooting and where things go wrong and the steps you are doing in a good positive way. thanks for your time doing this, it helps us all out
@bitoxic
@bitoxic 3 жыл бұрын
You just made my day Adrian! Big commodore fan here! Best way to cross 100k mark with this video!!! 😁👍
@MarcoHandleidingManuel
@MarcoHandleidingManuel 3 жыл бұрын
Adrian, i like your channel a lot. I am still flabbergasted by the way you are not using a ESD wristband, and tossing away the shielding. After fixxing i would put everything back to be a as close to the real machine. CIA's are vulnerable to static discharges known when touching the joystick ports. I like the way of your aproach with the hot air not to lift any traces. I would use the TL866-II to check the logic chips for faultiness.
@xiphias256
@xiphias256 3 жыл бұрын
Maybe he has it attached to his leg instead of the hand? ;-)
@mikeuk666
@mikeuk666 3 жыл бұрын
@@xiphias256 he said in previous videos he finds them awkward when filming so avoids them
@milandjukic88
@milandjukic88 3 жыл бұрын
100K! Congrats! Love your channel! Greetings from Serbia! 😊
@frugalprepper
@frugalprepper 3 жыл бұрын
Congrats on 100K Subs Adrian. You deserve more subs, but I am glad to see you got to 100K!
@tobiwonkanogy2975
@tobiwonkanogy2975 3 жыл бұрын
if anything this is the best way to know exactly what each logic chip affects , with an accompanying visual representation. Very cool Adrian
@00Skyfox
@00Skyfox 3 жыл бұрын
For those schematics that span two image files, just load them into a graphics program and merge the images, and then save the resulting complete schematic. If the original scans weren’t perfectly square you might need to tweak one or the other with some rotation or skewing to make things line up right.
@TheSleepyCraftsman
@TheSleepyCraftsman 3 жыл бұрын
As someone who worked in configuration management...manufacturing will say that a part is a part is a part, regardless of the revision. You're lucky that you get a revision on anything. If a change doesn't affect form, fit, function, interchangeability, etc, you won't get a new part number either.
@macdaniel6029
@macdaniel6029 3 жыл бұрын
I could watch your C64 repair-a-thons all day long :) Can´t wait for the next video.
@projectartichoke
@projectartichoke 3 жыл бұрын
Always love all your videos, but especially anything Commodore! Words to live by: "Run every diagnostic you can, first." :) I can't wait for you to hit 100K subscribers! At least I won't have to wait very long. :)
@dunebasher1971
@dunebasher1971 3 жыл бұрын
17:43 Love how the sound of the desolder gun forms part of the rhythm track on the music.
@AureliusR
@AureliusR Жыл бұрын
What? It's not in sync at all. I must be hearing something different
@Dorff_Meister
@Dorff_Meister 3 жыл бұрын
You'r "off by one" aside was the really useful observation. This must demonstrate a bit about your failure and HOW dead-test is checking RAM. There is something interesting there that I suspect the Dead-test author could learn from that bad RAM chip. I would send it to them. (too late it's in the bin, but I knew it would be)
@terosaarela4555
@terosaarela4555 3 жыл бұрын
Thanks for the video! A cold beer after sauna and watching your repair videos really make my Saturday evening!
@The.Doctor.Venkman
@The.Doctor.Venkman 3 жыл бұрын
Great video, Adrian! You know there is always going to be some creep that is sitting there shouting "It's the RAM allocated to the screen. One of the chips is bad...." - I have to admit, that it was me this time and boy, was that a very lucky guess as I'd be crying into my pillow if it had been something else lol! ;o)
@BigDaddy_MRI
@BigDaddy_MRI 3 жыл бұрын
Great video!! 100K coming soon I hope!! And your skills with troubleshooting C64’s are just fine. Test equipment can sometimes lead you down a path that takes you away from the actual problem. The old saying (from when I was in the Navy) is: trust your test equipment, until you can’t. Working on aircraft fire control computers ... sometimes our TE would lie to us and make the job harder. But, it happens, and you did a superlative job working through it. Maybe the dead test module needs an upgrade? Really liked this one, Adrian!! Great job!!
@markwrightrf
@markwrightrf 3 жыл бұрын
I waited so long to hear your catchphrase, "would you look at that? It's WORKING!!!" only to be hugely disappointed. I'm now doing a sad 8-bit dance shuffle to the Monty on the Run high score theme. "Would you look at Black? He's SHIRKING!!!!" :-) :-)
@krnivoro1972
@krnivoro1972 3 жыл бұрын
Loved the part you got confused with the three suspected chips in you ZIF motherboard just because some poor chip legs contact. That's the worst "I'm lost" moment you can get... 😁
@LFOSyncToo
@LFOSyncToo 3 жыл бұрын
Testing the dead ram chip in the ZIF64 would have been fun... for the giggles :)
@claudioquintanilla1471
@claudioquintanilla1471 3 жыл бұрын
I enjoyed this video a lot!!! Better than a suspense movie!!! Thks Adrian!!!
@tim_nj_devil176
@tim_nj_devil176 3 жыл бұрын
70's Shag carpet...beautiful green & gold mix - Jeff Foxworthy (1993)
@aaronkosharskyswhiteknight5224
@aaronkosharskyswhiteknight5224 3 жыл бұрын
It really tied the room together
@djdublo
@djdublo 3 жыл бұрын
Fascinating, genuinely absorbing! Never had a c64 but it's interesting to see how all the components interact.
@ConnerBurns
@ConnerBurns 3 жыл бұрын
Adrian is doing another repairathon? Finally, something to look forward to during human malware!
@80lab38
@80lab38 3 жыл бұрын
The bad SID and control port readings are in deed caused by a failed paddle test. I had the exact same reading when I replaced an 8580 with a 6581 and forgot to change the caps for the filters and the paddles (I didn't neglect to change the zener for the supply voltage, so the chip itself was working fine). So the test seems to be quite thorough.
@mdofxds
@mdofxds 3 жыл бұрын
Great work, Adrian! RAM issues may be really hard to diagnose. The worst case I meet time to time is when the most of available tests pass, everything seems nice and working but real programs glitch occasionally and randomly. This lead me to start making own tests for the machines I repair. I found kinda good heuristics which reveals such hidden problems: fill RAM with increasing bytes, check, cyclically shift the contents of RAM byte-wise, repeat from "check". Usually a couple of iterations is enough to reproduce the glitch.
@maltoNitho
@maltoNitho 3 жыл бұрын
Whoa, so close to 100k!! Congrats and thanks for the years of entertainment
@bozimmerman
@bozimmerman 3 жыл бұрын
@Adrian - in answer to your question @12:58 "Why don't the schematics at Zimmers.net note the board revision for those schematics", it's because the schematic scans don't have board revisions written on them, and over 20+ years of maintaining the site, no one has ever mentioned it to me. Well, now I know. Expect a reference there in 10 minutes.
@OzRetrocomp
@OzRetrocomp 3 жыл бұрын
0:44 Is that a new record for earliest Rick Roll in an ADB video? 😁
@TheRetroChannel
@TheRetroChannel 3 жыл бұрын
Approx 1 minute later: dead test is not always accurate 😉
@adriansdigitalbasement
@adriansdigitalbasement 3 жыл бұрын
HAHA -- It's time I update the display to show some different things. Maybe I can install my own logo or face on it. KZbin-Ception.
@thoraldshib4393
@thoraldshib4393 3 жыл бұрын
@@adriansdigitalbasement when is mac portable from macreparathon happening
@IanSlothieRolfe
@IanSlothieRolfe 3 жыл бұрын
@@adriansdigitalbasement What is that gadget? Do you have a video on it?
@thunderbolt10031
@thunderbolt10031 3 жыл бұрын
If you're like me and don't have a solder sucker, there's a neat trick to desoldering an IC with solder wick. On the underside of the board, of course, start there and get as much solder off as you can. Then flip to the top side and if there's enough room, run the wick against the legs on the IC to suck up any more that may have been left behind on the top side. Typically when I do it on 14 or 16 pin ICs, there's always at least 1 pin that doesn't completely desolder, but with a little patience, it'll clean up and the IC will just lift right out.
@wimwiddershins
@wimwiddershins 3 жыл бұрын
These are always enjoyable and compelling viewing. Thank you Sir.
@RoelvandenBergWillemWasbak
@RoelvandenBergWillemWasbak 3 жыл бұрын
For everything is a first thing to happen. So now you know that the death test does not always work well at one test, so next time test both or more versions of the death test. It makes you only a better troubleshooter with extra experience. I loved the video again so thumbs up!
@DavePoo
@DavePoo 3 жыл бұрын
I've got a board at the moment where there is something wrong with the communication to the RAM. The dead test ram test passes but the Diag cart test does not. Seems the diag cart version of the test is more thorough. I suspect what could be happening is that sometimes when the ram goes bad, the bits don't flip straight away and may take some time to go bad. I think a ram test that just does a write then read won't find errors like that.That's my theory anyway.
@petesapwell
@petesapwell 3 жыл бұрын
As always great to share this journey. Sharing is everything. Cheers Adrian 🤓
@pipschannel1222
@pipschannel1222 3 жыл бұрын
"It LIED!" Darn you Deadtest! Lol! Could've been me, getting stumped by yet another crusty old machine :-)
@SidneyCritic
@SidneyCritic 3 жыл бұрын
The IC puller is probably not good for large IC soldered on to PCBs. Saw that Parfractive guy snap a 40 pin in half when he didn't desolder a center pin properly - lol -. For the RF shield I was thinking a large 100W hardware iron with the copper tip hammered flat to a chisel shape, so it can heats and get under the tab on one motion.
@TechBench
@TechBench 3 жыл бұрын
For testing 74-series TTL and 40-series CMOS chips, you can use the MiniPro 866. Under device, select the "Logic IC" and then select or search for the one you need to test. Works for all gate-type chips (not counters, for example).
@briangleeson1528
@briangleeson1528 3 жыл бұрын
Another awesome video. I really enjoy your videos and applaud the effort you put into keeping these machines going.
@awebuser5914
@awebuser5914 3 жыл бұрын
At 33:34 you can see the display momentarily shift to correctly say "BAD" and shift other characters into different states. This may have helped in diagnosis!
@Dukefazon
@Dukefazon 3 жыл бұрын
After years of dreaming an accessible and affordable desoldering gun, I could finally get one (wasn't too cheap but cheaper than a professional one with a station). This week I used it to desolder one of the analog stick in a PlayStation 4 controller. It has 3+3 legs for 2 potentionmeters, 4 legs for a button and 4 structural points of the whole analog stick housing. It used to be a very difficult process but now that I have this desoldering gun I'm so happy and I can do jobs like these much easier and makes repairing stuff fun again.
@UberAlphaSirus
@UberAlphaSirus 3 жыл бұрын
Yhea. I really need to get one, solder suckers are ok for a few joints but otherwise are a PINA. What did you get?
@IRTheBorg
@IRTheBorg 3 жыл бұрын
You did well on this one. If it was me I would have went nuts! Great video - thumbs up! -Larry
@Renville80
@Renville80 3 жыл бұрын
Perhaps the drill should be to make sure it at least responds to the dead test cartridge first, and as soon as you confirm a understandable display, then switch to the full diagnostic cartridge for analysis. As for the shield, you may want to save a sheet or two of that insulation, it’s called fish paper and often used for insulating barriers around energized parts.
@UberAlphaSirus
@UberAlphaSirus 3 жыл бұрын
I thought a bad 0 or 1 bit too, due to the regular but close char offset. But the diag thru me off too.
@kd5byb
@kd5byb 3 жыл бұрын
I love repair-a-thon! :) When it comes to troubleshooting...some days you win...some days you don't. The key is to keep on keeping on. :)
@drkilmerx
@drkilmerx 3 жыл бұрын
Really enjoy watching your videos. Thanks!
@loginregional
@loginregional 3 жыл бұрын
Haven't watched any of it YET (and I will!), and I tend to criticize dialogue/monologue: you say (regularly) "let's get right to it!" But then you roll the retro (icky smeary video the type I haven't seen since 1994) intro. You see, you don't get *right* to it. I know this is going to be a great episode.
@GORF_EMPIRE
@GORF_EMPIRE 3 жыл бұрын
I suspected a ram chip from the get go, but since I never did any C64 repairs, I figured I'd watch and see. The period characters on the test screen is why I thought a ram chip was bad.
@jameslewis2635
@jameslewis2635 3 жыл бұрын
I have been told that the C64 was the most successful home computer ever made. While I don't know how many were made it does seem that sometimes between Adrian or Jan Beta have at some point half of them have been repaired on KZbin.
@Dukefazon
@Dukefazon 3 жыл бұрын
26:28 - I though your thinking was on the right track but not the chips that are bad but one or more trace is. Check continuity between the chips' legs. Those pesky RAM chips, making things complicated... Can't wait for next weeks episode!
@SimonZerafa
@SimonZerafa 3 жыл бұрын
Deoxit that Socket! 😀👍 I wonder if there is a bug in the code for the Dead Test, specifically for the RAM testing routines?
@johue2458
@johue2458 3 жыл бұрын
Perfect Sunday afternoon!
@HeyBirt
@HeyBirt 3 жыл бұрын
Heat the tab on the shied and pry it up with a small screwdriver. Very quick and easy.
@Dorff_Meister
@Dorff_Meister 2 жыл бұрын
I recently got a C64 with one of the S100 PLAs. Nifty.
@notneb82
@notneb82 3 жыл бұрын
Congratulations on 100K!
@6581punk
@6581punk 3 жыл бұрын
I think it was Bil Herd or someone from Commodore who said they are surprised the machines are still working given that one of the issues MOS had was poor sealing of the actual chip package, so the internals would get exposed and oxidise etc.
@Muldrf
@Muldrf 3 жыл бұрын
The Easy Flash issue is with the reset circuit of those boards. I have one and have the same issue with resets, there are a few options on how to mod it to work. I haven't gotten around to it though on mine.
@-CrippledNinja-
@-CrippledNinja- 3 жыл бұрын
Ooo, this was like an episode of Hercule Poirot! Which chip is the faulty one? Damn RAM chip again! What a thriller!
@TheBookaroo
@TheBookaroo 3 жыл бұрын
Hi again, also in the manual for the diagnostic they talk about 2 capacitors C48 and C93 have to be 1800 pF they sometimes have a different value that also makes the port test fail.
@winstonsmith478
@winstonsmith478 3 жыл бұрын
Your mention of schematic version vs PCB version difficulty brings up my question about no available 'scope images taken at various key test points. After all this time, with all of the people repairing the huge number of broken C64s, I'd have thought someone would have taken some photos to do that by now. Maybe they have and I just don't know it. Don't own a C64 myself.
@willbarnz6960
@willbarnz6960 2 жыл бұрын
On the 74LS258, pins 2 and 5 are inputs, as are 3 and 6. Datasheets can be your friend.
@GreenAppelPie
@GreenAppelPie 3 жыл бұрын
The board number in the documentation may be the latest PCB version, but there weren’t any circuit changes. It may be little hard to see changes like internal power or ground planes, changed vias and the like. It is sloppy documentation IMHO but for the time it was common.
@sausageeater9357
@sausageeater9357 3 жыл бұрын
Knew it would be a ram issue, that was my first impression. It's the same with many issues with the Sinclair Spectrum. Bloody ram lol. BTW, love the videos Adrian 😍
@rfmerrill
@rfmerrill 3 жыл бұрын
If it were me I would get out the heat gun and freeze spray and see if I can turn it from working to non-working or vice-versa by heating/cooling specific chips. Very good general tool for debugging as often a fault in a chip will fix itself at high or low temperature (usually low).
@XLV750RD01
@XLV750RD01 3 жыл бұрын
Congratulations on 100k subscribers.
@ownpj
@ownpj 3 жыл бұрын
24:00 If only you followed the schematic before desoldering you'd see the "screwy" (floating) inputs come from CIA2, that you removed.
@adriansdigitalbasement
@adriansdigitalbasement 3 жыл бұрын
You're absolutely right! I realized that after
@LeftoverBeefcake
@LeftoverBeefcake 3 жыл бұрын
Yup, for a little constructive criticism, I think that this should be mentioned first and foremost - you have to get your hands on some schematics and/or troubleshooting guides. To be fair, that depends on the machine though, because a popular computer like the C64 will have tons of troubleshooting material available whereas other rarer machines may not.
@stevem.1853
@stevem.1853 3 жыл бұрын
@@adriansdigitalbasement No worries, failure often teaches us more than success & persistence paid off in the end 👍
@chewyfoks1840
@chewyfoks1840 3 жыл бұрын
@@LeftoverBeefcake It's fantastic that Adrian leaves all his problem solving in his videos, and has schematics to hand! It's like watching a mirror image of 90% of his audience fumbling and trying different things. We all do it, and that's why it is such a great educational tool.
@deborahberi3249
@deborahberi3249 3 жыл бұрын
Oh boy, I learned that a few years ago. Full Diag Cart is my goto UNLESS it won't run at all. Too bad Dead Test failed me in the past so I don't rely on it for RAM Tests. -Mark.
@davidschneider1074
@davidschneider1074 3 жыл бұрын
Adrian, nice video!!! Question, where do you get those chip sockets and that tool that straitened the pins on the chips? I have some of my dads Vic 20s and those tools and supplies would help! Thanks for the videos!
@P5ychoFox
@P5ychoFox 3 жыл бұрын
Great journey. Glad you got there in the end. Another C64 fixed :))
@WY.C64-Guy
@WY.C64-Guy 3 жыл бұрын
I was contemplating what to do with my Rev. A board. Maybe I will restore it and give it a chance. Adrian, I know you talked in other videos about improving the VIC-II output, but I can't remember if Rev. A boards were included in that discussion? I guess I'll have to go back and re-watch those. I know that one of the factors facing a Rev. A is the absence of separated chroma and luma output circuitry. (The VIC-II has it, the Rev. A just doesn't provide it at the video port, which is why it is only 5 pin.)
@SocrateTheCat
@SocrateTheCat 3 жыл бұрын
Thanks Adrian for your video. Dead test cartridges don't always tell the truth. I have a commodore where the cartridge tells me that everything works (with harness) but when I run the load command to load floppy it hangs and does not give up control. I tested several disk peripherals (1541 and pi1541) and I have the same thing. The cable is good too. The u8 (7406) is good too. I tear out what little hair I have left. :)
@AureliusR
@AureliusR Жыл бұрын
I was surprised that you immediately discounted the RAM as the problem. Whenever I see a repeating, weird pattern on screen that just screams "dead bits in RAM" to me. And as others have said (though I didn't know this) the dead test doesn't test all the RAM possibly?
@zaanpenguin
@zaanpenguin 3 жыл бұрын
@Adrian's Digital Basement Perhaps this dead test uses a specific static bit pattern for testing, one which would not reveal the off-by-one least-significant-bit error? That could explain why it corrupts the screen, but still passes the checks.
@Halftrip
@Halftrip 3 жыл бұрын
I anxiously await any and all of your Commodore 64 videos, regardless of their content. But I especially like these fixit videos. Pulled my breadbin out to try and get it running. Deadtest says everything is fine but diagnostic cart (with harness) says both CIA chips are bad. Awaiting some replacements in the mail to see if that’s right. Can’t wait for your next video!
@schm4704
@schm4704 3 жыл бұрын
Oh come on... that opening shot of those stacked 64s is just flexing. :-)
@OscarSommerbo
@OscarSommerbo 3 жыл бұрын
You mentioned you had no way of testing logic chips, that is incorrect. The minipro can test TTL logic chips.
3 жыл бұрын
Also, the logic testing function has been much improved in the latest software release. Worth an upgrade!
@MattKasdorf
@MattKasdorf 3 жыл бұрын
Does the Linux version of the software have a test feature?
3 жыл бұрын
@@MattKasdorf No. The linux software is not supported by the vendor and does not provide logic chip test functionality.
@waynej41
@waynej41 3 жыл бұрын
@@MattKasdorf Works running it using wine. Well, does for me anyway.
@douro20
@douro20 3 жыл бұрын
The 82S100 was actually the very first user programmable logic device.
@RavenWolfRetroTech
@RavenWolfRetroTech 3 жыл бұрын
Nice, I love a good repair!. My "Luck" on fleaBay has been terrible. I keep buying "Dead" machines only to discover they work fine or have a bad power supply. I need a Fix Fix!
@jean-francoiscaron5706
@jean-francoiscaron5706 3 жыл бұрын
Have you considered buying/building a dedicated 74-series logic tester? I see many results googling for that, and there's a recipe on Instructables.
@herdware
@herdware 3 жыл бұрын
My first thought was bad RAM but then the Dead test said it was OK. At least it made an interesting video.
@adamwheeldon
@adamwheeldon 3 жыл бұрын
Love a good repair-a-thon 👍👍👍
@fabriciocabral3987
@fabriciocabral3987 3 жыл бұрын
Hi Adrian! Congratulations for the fix! Can you say where did you buy these sockets (not the ZIF ones)?
@Gorgen2k
@Gorgen2k 3 жыл бұрын
Dunno why i find these vidoes fun to watch when i dont even have a c64. I had when i was younger, but i think remember ours died because the fuse was going always. And i think it was imposible to get new ones in my town at that time.
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