Disgusting Commodore 64 Repair (Part 2)

[@JVHShack]

The original sockets were called (at least here in the USA) "single wipe". You're correct about them being total garbage! 😅

[@Xoferif]

They're called that here in the UK, too. =) The better sort with two spring leaves per pin are called "dual wipe".

[@NoelsRetroLab]

That's right! I knew that and I was totally blanking on the name. Thanks for the reminder.

[@blahblahblahblah2933]

That microscope is very well labeled, no question about it!

[@NoelsRetroLab]

Yeah, you wouldn't want to accidentally grab the microwave oven instead!

[@jonyballistic]

🤭Good one

[@blahblahblahblah2933]

That distortion from char rom flexure is amazing! Great video.

[@NoelsRetroLab]

Right? That was really weird! Now I'm wondering if that screen with colored lines was done with characters or graphics because that was also getting distortion when I was pushing on that chip. Pretty bizarre!

[@Vampier]

Before you know it a demo group will make use of it :) you know they would! ;)

[@birdman8649]

@@NoelsRetroLab That was fun indeed and might be even more fun to thing about what could cause it. Would have been fun to see whether pushing or moving that SID made it sound any different because it was at least trying to work. Maybe SID also had some weird contact issue like insufficient power or ground or signal connection. So far I haven't seen any detailed analysis of failed chips although that would be very interesting but likely also very difficult.

[@preferredimage]

8:10 Commodore, built to last, extra engineering just in case.... Amstrad "How cheap can we make it?"

[@WilliamHostman]

I believe the term you wanted for those sockets is "single wipe" for those, and "dual wipe" for the much preferable ones.

[@NoelsRetroLab]

That's right! I was having a mental block at the time. Thanks.

[@atzefatze]

I cant say it enough; I really enjoy how you solve problems, amazing!

[@NoelsRetroLab]

Glad to hear it!

[@LongyFromCork]

Well done Noel, another C64 brought back from the grave. Love your channel. A SID replacement comparison is fantastic idea. Looking forward to that one if you get around to it. Alan, from Ireland.

[@NoelsRetroLab]

Hey Alan, glad you liked it! Yes, I'm already setting things in motion to do that SID video at some point. Things take a while (order parts, figure out how to do it, film it, edit it...) but it'll happen eventually. Cheers!

[@pcroom34]

Agree a SID replacement chips video would be a good idea, as I hope to buy the ultimate 64 or something similar so will definetely need that replacement chip from you Noel, you could start a shop, your reputation is ace!!!

[@rageagainstthebath]

I really like how you show a diagram with a little scope probe to keep track of what you're showing on the scope. Fantastic way to spend a nice evening with a glass of wine and watching you doing fun repairs. Greetings from space electronics industry. :)

[@rageagainstthebath]

HOWEVER, if you're asking for a bit of criticism, when looking for ANY changes in logic signals, I'd set the scope trigger level between 0 and 5V, so you could be sure no transition is missed. :)

[@NoelsRetroLab]

Thanks! Yes, you're right. I'm not in the habit of working with triggers much because the signals I use are not periodic, but that would be great for single captures of things happening at startup like here.

[@KolliRail]

Another great troubleshooting video! You are really playing in a league with Adrian and Co!

[@NoelsRetroLab]

Thank you!!

[@HAGSLAB]

Wow! I can't believe that stuff was just on the surface and scraped off without even taking the solder mask with it. That is amazing! 😁Watching you fix this C64 really makes me want to do some more C64 work as well. Luckily I have something coming up 😀

[@NoelsRetroLab]

I know, right? That was a HUGE surprise to me. I was convinced at least 3-4 tracks there were completely dead.

[@3DPDK]

As far as I know, the C-64 SID used several internal capacitor filters to isolate the system clock and digital activity on the address and data buss from the audio portion of the chip. This was additional to the external .01 power line, ceramic caps. If the internal filters failed or became marginal the digital noise could bleed through. It didn't affect the oscillators, but the noise would get into the output amplifier. Actually on most C-64s, if you set the volume to 15 and turned the volume all the way up on the monitor or patched it into an external audio amp, you still could faintly hear the digital noise, but the level varied from one chip to another. As a field tech and bench tech, I learned rather quickly never to abbreviate the remove and replace process the first time - especial if your instinct tells you. A few extra dollars in parts vs several more unpaid labor hours the second time the device hits your bench; this time under 90 day warranty from the last repair. Also; a fine "green scrubby" and a dab of white or distilled vinegar will get rid of oxidation. It won't damage the traces or the conformal coating. Using a needle, Exacto-knife or dental pick risks damaging already brittle and fragile traces, or can scratch the coating giving moisture a path to the copper below. Rinse and dry with PCB cleaner since the vinegar residue can cause further oxidation in humid conditions .

[@NoelsRetroLab]

Interesting about the internals of the SID. But this SID couldn't have been like that from factory, right? I mean, it kind of sounds OK, but super, super low volume and with lots of noise. Maybe some of those filters failed like you said.

[@3DPDK]

@@NoelsRetroLab Not likely, but not impossible to have a batch of new chips with a contaminated capacitor dielectric layer (causing leaky capacitors throughout the chip) If the chip is brand new, it's definitely a manufacture defect, or it may have been exposed to static discharge which tends to burn through dielectric layers.

[@bobbus_74]

You got there in the end Noel. It was really interesting to see actually. 👍

[@NoelsRetroLab]

Thanks! It was a fun trip.

[@bobbus_74]

@@NoelsRetroLab as always! 😁

[@TimToolman]

The armSID is the best substitute SID i have tried, so definitely recommended looking at them.

[@NoelsRetroLab]

Already got one here! 😃

[@Breakfast_of_Champions]

About rebuilding the edge connectors from 17:03, there is also (pretty expensive) conductive paint that can be used for this job and even on flex cables. During your soldering you can see how the spots immediately oxidize rust-brown as they get hot, it would be better to cover the area under flux. This board had quite a bit of damage, I still think there must have been some additional acid in the air where it was stored. Good job!

[@GORF_EMPIRE]

Excellent job cleaning up that C64! My guess is the die of that ROM chip got weather worn over the years and the leads internally were intermittent.

[@NoelsRetroLab]

Thanks! Yes, exactly. The rust on the legs probably continued working its way inside the chip and caused intermittent connections.

[@yereverluvinuncleber]

I am always amazed that you are happy to apply full power to any PC without a rheostat involved bringing the power up slowly, especially when the original power side caps and voltage regulators are still in place. I always bring my repaired machines up slowly and watch any power drain. That is my only suggestion to you. I like your videos despite never owning a Commodore ...

[@NoelsRetroLab]

Thanks! That's actually a really interesting suggestion, and to be honest, I almost never see it done, but it makes sense. When I can I'll power the computers from the bench power supply with a current limit on, but I've never gone that far. Would this rheostat be in the mains side of the power supply I imagine? Does it show you the current power being drawn? Any recommendations for one? Cheers.

[@yereverluvinuncleber]

@@NoelsRetroLab I work with legacy systems and powering them on is the biggest worry , if we can be gentle to old power circuits bringing them up slowly then it pays dividends as you don't ever want to have a component fail during an instant full power load. A voltage spike is not something an old board can easily handle as there is very little in the way of protection circuitry in these old motherboards. A crowbar circuit would be ideal but in the absence of that a variac is a way to bring up the voltage gently.

[@tonanornottonull7132]

Ugh those single-sided contact sockets are the worst. Glad you got it up though! Those traces were pretty questionable before you sorted them out.

[@NoelsRetroLab]

Yeah, I was convinced the traces were gone. I was so surprised when they turned out totally fine. Other people seemed to think it wasn't even rust, but some kind of crud.

[@luisrodrigues7162]

Great video. Always learning with your excelents repair tips. Keep on the quality. Greatins from your brother country Portugal.

[@NoelsRetroLab]

Awesome, thank you!

[@sephyp1611]

Great job. I'm a C64 repair video addict. However, in my experience it is never recommended to tin contacts since the solder corrodes faster than the (gold plated) contacts themselves. I would have recommended looking for some dedicated contact cleaner instead or try to mechanically scrape it out (maybe under the microscope). But hey, it now works! Very nice job. Please keep at it. Thank you.

[@80lab38]

Since you asked for it, here goes: I think tinning those edge connectors might have actually hurt more than it helped. It didn't remove any of the corrosion and all you really did was covering the gold with tin, which unlike gold is very soft and will rub off on connectors and cause issues there. That's why all edge connectors in commercial products are usually gold plated, unless they're really crappy. Next time just clean them with a fiber glass pen and some de-oxid, that'll do. It's not like those connectors would see the kind of use they did back in the day, after all. That being said, I really enjoy watching your videos. Keep it up!

[@NoelsRetroLab]

That's a good point. I had never encountered edge connectors this far gone, so it was my attempt at restoring them a bit, but I can see it might not be a great solution. I've seen videos where they regrow the material, but that involved a $300 kit, so that was out of the question 😃 Cheers.

[@frankowalker4662]

Can't wait to see the finnished case and it all reassembled.

[@NoelsRetroLab]

It's all done and sitting here next to me. I'm wrapping up editing that video at the moment, so coming soon! 👍

[@DavePoo2]

If you are doing SID replacement tests then it's worth checking out the Level 1 music from Ghouls & Ghosts. The bassline is totally missing on the 8580 compared to the 6581. I've noticed the emulation in VICE (was using BMC64) actually emulates that correctly as well.

[@NoelsRetroLab]

Oh, great tip! Saving that for later.

[@fresita_jugosa]

Great job! I'll definitely watch out for the next one, I want to enjoy the paint job :D about the rusty tracks, It's good idea to check continuity, but check for shorts as well (if you aren't already doing it). After that, give the rust spots some deoxit (you have a pretty good one available in Spain: 3 en 1. It's similar to WD40, and was invented the same year. Give it few seconds to act and then rub it with the brush. Clean it with some isopropyl alcohol and then apply the lacker (nail lacker works just fine). That's future-proved! As you said those boards are pretty sturdy (I'd say "resiliant" :P) but it's always a joy to bring'em back from the dead

[@NoelsRetroLab]

Thanks. Glad you enjoyed it! I didn't realized that 3 en 1 was good for removing rust. I'll keep it in mind. Cheers.

[@T3000_retro]

Thank you for the great video. Especially the idea with the pictures of the measuring points and the measuring tip are a great help. Many thanks for that.

[@YogSothoth1969]

Very cool videos Noel, I enjoyed them very much. I always love to gather as much information as possible for upbuilding my own knowledge in restoration of these old, wonderful machines. And thanks for the hint with the desoldered chips that still got solder on their legs that might resolder in sockets.. Keep up with your great works! Best wishes from Germany, Michael...

[@NoelsRetroLab]

Thank you. Glad you enjoyed them!

[@lordmuaddib]

loved the work on the external connectors!

[@NoelsRetroLab]

Thanks! It's the first time I've had to do something like that with an edge connector because they were so far gone. Normally some scrubbing will do it but those... yikes!

[@valentine_puppy]

Adrian's Digital Basement has a recent video on the dead test cartridge not showing real problems. It a great video. I believe it's on his C64 number 3 machine repair-a-thon.

[@NoelsRetroLab]

Yes, the Dead Test Cartridge is not great. It's good for some things, but it will often fail to detect things like it happened to me last time with the RAM. And yes, I watch every Adrian's Digital Basement video religiously 😃

[@RandallCrook]

Another great video. While I’m not a huge C64 fan, I do enjoy watching them get repaired. Something about the trouble shooting on them seems more approachable them other systems.

[@NoelsRetroLab]

Thanks! I don't know if they're more approachable, but they're more interesting! Also, tons of different things can cause black screens, so you really need to dig in. Other systems tend to me more straightforward since they have fewer parts, or boring if they just have one big chip that does it all and you can't replace it.

[@Ditt_o_datt_fran_bon]

Excellent vid. Thanks Noel!

[@NoelsRetroLab]

Glad you liked it!

[@minombredepila1580]

Amazing video!!. I always learn something new: today it was reviving the cassette tracks. I would really like a video on your Amstrad test (when you finished it) that could even be used as a "video-manual". You are doing an amazing piece of work with that test. Congrats again Noel :-)))

[@NoelsRetroLab]

Thank you! Glad you enjoyed it. And yes, I'm planning on having a video about the diagnostics ROM sometime. I just need to find the time to do all the videos I want to do!! 😃

[@minombredepila1580]

@@NoelsRetroLab I am very much looking forward to it!!!. Thank you again, Noel :-)

[@MrLandphill]

with all the work you do on c64s you should get a full diagnostic assembly. great videos thanks for all you do.

[@NoelsRetroLab]

Agreed! Got one already! Check out the latest Mail Day video 😃 It's awesome!

[@MrLandphill]

@@NoelsRetroLab i noticed that video right after I made the comment, I was running your videos oldest to newest.

[@Charleshawn66]

Another really good video from you!! Very professionally done! I'm enjoying this series and moving on to part 3 now.

[@Wraithan]

Really enjoy your videos, really enjoy the small editing touches like the little extra zoom before Xing out the char ROM.

[@NoelsRetroLab]

Thank you very much! I figured I was the only one who would notice little touches like that, but I'm glad someone else enjoys them too 😃

[@JoeMcLutz]

...One of the weirdest cases I've ever seen! About CharROM, I think the corrosion has "traveled" to the thin internal connections in such a way that it makes a bad contact, which varies with the pressure of the chip. But it is only a hypothesis. Amazing video and a great job as usual! 👍😊 Thank you! PS: I would try to open that chip to see under the microscope if there are traces of corrosion in the connections between the pins and the core, just for curiosity... You could do a "forensic episode" about that! 😂

[@NoelsRetroLab]

Yes, exactly. I've been seeing that quite a bit lately in other repairs: rusted legs of chips == dead chip, even though all the legs make contact correctly. Good point about looking inside. I was planning on doing a video about that with the fake chips, but I might try it with some of the rusted ones if I perfect the technique and I don't destroy all the insides 😃

[@JoeMcLutz]

@@NoelsRetroLab All the best Noel! I'm looking forward to watch this episode!

[@GodmanchesterGoblin]

@@JoeMcLutz I am sure you're right about that. The corrosion could easily spread along the lead-frame into the resin encapsulation and would then attack the bond wires to the die. It would also cause fractures in the resin allowing more moisture to get in and then further corrosion would follow.

[@JoeMcLutz]

@@GodmanchesterGoblin yes indeed, but my doubt concerns the possibility of oxidation of the conductors inside the chip, that is, in a place where oxygen should be absent ... Perhaps the external oxidation of the pins (and in the points of contact of these with the chip) creates "gaps" through which the oxidation inside makes its way.

[@GodmanchesterGoblin]

@@JoeMcLutz That's what I am saying. We are in agreement. And it happens often that just a little some moisture can get inside. This C64 was just an extreme case due to how it had been stored.

[@mattcole6230]

Brilliant video! Would love to see the modern chip equivalents.

[@NoelsRetroLab]

Coming soon! 👍

[@divarin1]

With the card edges I thought you might try some Brasso. I've used that in the past, it's easy and effective. In your case though the pitting may have been too extreme for that so putting down a thin layer of solder was probably the best option.

[@farerse]

I'm addicted to your videos, I need to go to rehab :(

[@NoelsRetroLab]

Haha, well, you can get your fix every Thursday at least 😃

[@farerse]

@@NoelsRetroLab thanks lol

[@doktor6495]

Hi Noel, nice job! REMEMBER! The CHAR ROM you can only replace with an 2532 EPROM! BUT ... your EPROM programmer MiniPro TL866 can not handle 2532 EPROMs :-( Or you have to use an EPROM adapter for a 2732. Best regards! Doc64!

[@NoelsRetroLab]

Right. I used the ol' adaptor trick with a couple of sockets. Not pretty but it works. I need to print out some real PCB adaptors to make it much neater.

[@WacKEDmaN]

nice job yet again Noel!... that "bad" SID could possibly just need the pins cleaned.. i woulda tried it just coz the chip is hard to source

[@NoelsRetroLab]

Yes, I didn't want to make the video even longer, but I did give it a good cleaning and... nothing. No change at all. It's dead, Jim!

[@WacKEDmaN]

@@NoelsRetroLab bugga!

[@rageagainstthebath]

Probably could be replaced with AVR on an expansion board, just like the other chip that Noel put in place of the one above it, can't remember its name. It may not seem "authentic", but hey, replacing memory and logic chips with modern equivalents isn't much of a difference. For the sake of restoring these classic machines, I guess this is a fair trade-off to use modern clones of these classic ICs.

[@kai990]

0:34 glad it says microscope right there. For a second i i was about to close the window, thinking it was sports.

[@TMS5100]

@23:32 brass brush is fantastic for removing grime and corrosion from pins.

[@tomscomputerchannel2925]

That’s a repair with some surprises. The microscope is very useful for those inspections.

[@EricsEdgeVideos]

Interesting restoration. I just picked up my first C64. I've been restoring Apple Macintosh computers for a couple of years. This C64 has some water damage. The shield paper was torn off. And the video RF shield is rusty. None of the chips are socketed which may be a blessing and a curse. We'll find out once I build a power supply.

[@MrMaxeemum]

It's worth building (Ray Carlson has some good diagrams) or getting a harness for testing, I have found many issues which otherwise would have gone unnoticed. Also I find many chips fail after 1 or 2 hours then work again once cooled down. Highly recommended.

[@NoelsRetroLab]

Yes, I already ordered a set actually. They seem super useful. And you're not kidding about chips shutting down after some use. The PLA died on me after about half an hour!

[@Revoku]

a typical soft white or red pencil eraser works great at removing connector corrosion and trace corrosion with minimal to no damage, I live in a thermal area and the sulfur makes even gold coated contacts corrode, I am forever having to remove ram sticks, and hard drives and clean SATA connectors/ddr3-4 ram connectors here(I have the soft white style pencil eraser atm) in my area they get black copper corrosion spots that come up thru the gold plating in under 3 months(a little bit worse than that edge connector but not by much) and the pencil eraser does an awesome job

[@Aruneh]

I like the Gold and silver pens used for marking the chips, very bling bling. ;)

[@NoelsRetroLab]

Haha, I used to use a black marker, but you honestly couldn't tell the chips that had an X from the ones that didn't most of the time. This is so much better! (and gold vs. silver... they just came in the pack this way, so I figured I'd make the most out of it 😃).

[@jameshearne891]

I think the corrosion was more likely some sort of mould, from somebody eating their lunch while the board was made or repaired.

[@GodmanchesterGoblin]

I was going to say similar - either that, or maybe residue left by small insects and spiders. But most likely just a mould caused by dirt and damp, given how dirty the board was in the first video.

[@awilliams1701]

yes when I lifted the trace on my cartridge slot I found it difficult to find the source, but I did manage to track it down. I can always bodge it if I need to, but direct soldering to the new connector seems to work just fine. It didn't fully lift the trace. Just a CM or so.

[@TranceTrousers]

I love these troubleshooting/repair/ refurbish videos. Looking forward to seeing the C64 when it's all done, I presume you'll be respraying the case? On a side note, I got my previously working C64 out and tried it the other day but just got a black screen, any ideas as to what might be the problem?! Thank you :-) P.S. this is definitely one of my new favourite channels!

[@NoelsRetroLab]

Hi Chris! Glad you're enjoying the videos. I'm wrapping up Part 3 and should be ready in two weeks (indeed, with spray painting!). Black screen can mean just about anything on a C64 unfortunately. Check out some of my other C64 videos (there's a playlist with them) and try to follow the general flow: voltages, clock signal, video signal, Dead Test Cartridge, etc. If you need some help, hop on over the Discord server and there you can post pictures and tell us how it's going and we may be able to help. Good luck!

[@TranceTrousers]

@@NoelsRetroLab I will do that Noel, thank you. I just wanted to say that your English is superb and that you put many native speakers to shame! I also love that your daughter is so interested in these vintage machines as well as programming them and even doing a bit of soldering! Mine is a similar age (she's 11) but unfortunately not interested in any of my collection of vintage computers at all :-(

[@Flamelily-IT]

Noel: These C64 are bullet proof, much better than the Amstrad. Cue multiple faulty chips 🤣 Great video though👌

[@NoelsRetroLab]

Haha, in my defense, I was talking about the board itself, not the chips. The chips on the C64 are notoriously fault-prone, but the boards are tank-proof pretty much. I mean, look at the state of this one!

[@Flamelily-IT]

@@NoelsRetroLab Fair enough, maybe I misunderstood your comment🙃

[@patzik1910]

Hi Noel, nice repair, are you going to do something with the case, paint it or maybe hydrodip it? Anyhow, you mentioned that you don't have the harness for the diagnostics cartridge. How can I get in touch to ship one to you?

[@NoelsRetroLab]

Thanks Patrick! Yes, the case got the whole spa treatment. Coming up in two weeks 😃 Thanks so much for the offer to send in the harness, but I actually just bought one after the experience with this repair. Hopefully it'll get here in a week or so. Cheers! (PS. You can always get in touch through Twitter, Discord, or the email listed in the KZbin About page).

[@dazamad]

Nice video. I look forward to the side replacement video if you make it.

[@NoelsRetroLab]

Thanks! I've already started setting things in motion for the SID replacement video, so it'll eventually happen, although it'll take a while to get all the parts, prepare things, etc, etc. But it's coming 👍

[@stefanhaglund8395]

Great video, and very interesting. I’m learning a lot! I also have a question: I’ve seen that you sometimes check for CPU activity by probing the RDY pin, and I’m wondering if it wouldn’t be better to probe the SYNC pin? As I understand it, RDY is an input that halts the processor as long as it is held low, while SYNC is an output that the processor sets to high whenever it is fetching the next instruction. It would seem to me that SYNC would be a better place to probe for actual CPU activity?

[@NoelsRetroLab]

Hi Stefan, it's been a long time since I specifically tested for activity on a 6502 so I forgot the specifics. The SYNC pin seems like a good way to go, and seems very similar to /M1 on a Z80. You could also check with R/W probably, and, to a lesser extent, clock out.

[@projectartichoke]

I think the MOS branded chips produced between 1984 and 1985 had lots of reliability issues. Earlier and later chips were fine.

[@NoelsRetroLab]

Oh that's interesting! I didn't know there was a particularly bad period. I thought it was just about all MOS chips. Any idea why that time in particular?

[@jimwarb]

Another great video Noel. Is it not always necessary to replace the capacitors, or is that something you plan to do later?

[@NoelsRetroLab]

I usually only replace capacitors if I see/suspect they need to be replaced (or if I'm completely out of other ideas). Here they seemed fine, so I didn't bother with that.

[@SobieRobie]

Wow, this was a challenge! I would try to remove the rust spots from the back using some vinegar.

[@retrocomputeruser]

Thank you so much Noel for this video. I still think that the Amstrad CPC is much more reliable than the C64 because the IC's don't fail as much. Out of all the C64 and CPC videos I have watched, The CPC may have a single failed IC whereas the C64 usually have many at once. Maybe it is the MOS (CBM) branded IC's that have a higher failure rate than others. Then again, I would question if the CPC circuit board would live through the same conditions as that C64 and survive. At the end of the day, all retro computers are equally loved for their appreciation the technology had in that era of computing.

[@NoelsRetroLab]

I actually agree with that. What I meant is that the board, the PCB itself, is much more robust on the C64s. If you put the Amstrad PCB under similar conditions, it would be a corroded mess with high resistance in all its tracks.

[@ches74]

Rust on the tracks can only be a deposit. The PCB contains no iron. It could only come from a steel component e.g. the chip legs, shield or screws. Strange that it's on the underside but it could have been sitting in any orientation for years.

[@NoelsRetroLab]

Oh interesting! How weird the pattern and that it's on the underside. I'd love to know what happened there.

[@ches74]

@@NoelsRetroLab I wonder if somehow there was a little swarf from a screw of something sitting on the damp cardboard shield. We can only hypothesise.

[@tenminutetokyo2643]

Jam in all new tiny ceramic caps too for visual effect.

[@bobbobson4069]

This is the first time I watched your video! Enjoyed it enormously!

[@NoelsRetroLab]

Glad you enjoyed it! Welcome aboard! 😃

[@roratoria]

The best sockets are the machined (swiss machined, like MilMax) but good luck on getting any socket to work on DIP IC that have been de-soldered. Socket are all bad. If you want to save the chip break the board. If you want to save the board, clip the IC leads. If you want reliability do not use sockets, Solder the chip to the board. I try to save both and end up breaking more than I save.

[@patrickdeunhouwer5926]

Microscope seems like a great tool and this video reminds me to check the sockets of one of my not completely working c64 thanks….

[@NoelsRetroLab]

Glad you liked it. Good luck tracking down the problems in that C64!

[@gwesco]

I'm repairing a couple of Electronic Systems 106 TV Typewriters and most of the problems seem to be really bad sockets. Maybe due to age but I suspect the quality in the 70's for sockets was not that good. Great troubleshooting techniques and we all get caught with that "it's probably OK" once in a while. I really need to get a microscope as that lets you see the tiny defects in traces. You lucked out on those rusty traces.

[@MD_il_microcanale]

you did a great job, those tracks thank you! I had a c64 silver label with a similar disappearance problem, but in that case it was the vic II!

[@NoelsRetroLab]

That you would push on it and things would change on the screen? I've had that happen with a VIC II as well, but that was the socket in that case. As soon as I changed to a double-wipe one, everything worked fine.

[@MD_il_microcanale]

@@NoelsRetroLab in my case the VIC II was really broken. Tested on various mobos. At first it gave a black screen, then warming up it turned blue and then it started with gray and then black again. taking a fan and cooling it with a dissipatorino, little by little the writings returned. Unfortunately, even with the writings the C64 was unable to execute commands, the VIC II blocked everything! it was a 6569 r1, replaced with a contemporary one! for this then I have devised an invisible dissipation system, if the C64 has the VIC II box. This is a reversible mod that increases the dissipable surface of the VIC II and transmits heat faster to the box if it has one. kzbin.info/www/bejne/Y2jWnqmsg718i6c it works pretty well, too bad there is little airflow inside the C64 when closed. My c64 250425, on the other hand, being common, has become like this, since I often use it: kzbin.info/www/bejne/aYuukquYrN2YhKc this takes air from the slits above, through a rudimentary cardboard airbox and cools the entire interior. For prolonged use it is ideal!

[@jonyballistic]

Great video, problem solving kudos

[@NoelsRetroLab]

Thanks 👍

[@paulharker7184]

The "corrosion" on the traces is surely something that dripped down from the saturated RF shielding?

[@ElectoneGuy]

I like to replace those 40 years old electrolytic capacitors when restoring old C64 boards. Very cheap insurance.

[@LanceHall]

Some other people just spray the alcohol and apparently don't clean up the diluted flux as if it just magically disappears.

[@NoelsRetroLab]

Right. That just smears it on the board (and the brush probably takes some). But if you soak up the alcohol-with-flux mix with a rag, it leaves the board really clean.

[@CoverMechanic]

I’d have used some WD40 on that rust - does a great job loosening it so it just wipes away.

[@borayurt66]

Yep, came to make the same comment, you beat me to it. Just let it soak for half an hour, I am sure all of them will wipe away clean. They seem to be superficial, coming from something else. The soldermask did a great job of preserving the tracks.

[@cs121287]

Great video thank you Noel!

[@NoelsRetroLab]

Glad you liked it!

[@cs121287]

Just curious... what time is it by you? If I remember correctly, you are in the beautiful Spain? I am in the USA and its 5am here. Maybe you should make a video about you and what your life is like, like the work you do and your life in computing growing up. Something like a fan "get to know you" sort of thing. I think that would be fun.

[@ElectronGordo]

Great second part :) Noels, May I ask where did you get this test cartridge? Thank you

[@NoelsRetroLab]

The Dead Test Cartridge? I honestly don't remember. You can get it from many sources I think. The key thing is that it needs to boot directly into that, not into a menu first like EasyFlash.

[@ElectronGordo]

@@NoelsRetroLab After your experience here... Which one is the best in your opinion?

[@PianoZecora]

18:17 Buy yourself a fiberglass brush (named scratch pen/pencil in some areas). It is a bit abrasive, works amazing for rusty contacts...

[@DAVIDGREGORYKERR]

Had to update the kernel for the OS that I am running and if you are interested it is LINUX MINT CINNAMON 19.3 (Tricia) 64bit edition

[@geekyzombieking7594]

Loved the video! I hope to see more commodore 64 repairs like this one.

[@dazman76]

Great stuff as usual Noel, thank you. Keep it coming mate :)

[@NoelsRetroLab]

Thanks, will do!

[@alerey4363]

8:43 ten cuidado en confiar demasiado en el cartucho DeadTest porque a Adrian Black ya le ocurrio que confio en el, le dijo que tenia memorias RAM malas y resulto que no habia problemas en ellas sino en un multiplexor y se paso medio video desoldando integrados que no eran y luego volver a soldarlos para descubrir al final con el osciloscopio que el problema estaba en un multiplexor

[@TaberBucknell]

Excellent detective work as always! For rust on large items like the power connector there is a product in Canada called CLR (Calcium Lime Rust); I have no idea if it is available in Europe. It’s magic on corroded battery terminals too. Caution: If you try CLR please note that it is quite corrosive on its own. Once applied the area treated needs watched. Once clear of rust the area immediately needs flushed and cleaned (I use water first, then IPA). A few short treatments with CLR are better than one too long treatment. Finally, a question: Do you have a mini-vacuum or similar for cleaning up particles after sanding or using the fibreglass pen? Grit getting into repairs is something I worry (too much?) about.

[@AndrewTubbiolo]

I wonder if the bonding wires in the character ROM were losing connection? Perhaps a baking session would reset the internal connections?

[@NoelsRetroLab]

Oooh, tell me more about that, I had never heard of baking a chip to reset internal connections. Is that a thing? I would totally experiment with that. I wonder if that might help with the SID as well.

[@AndrewTubbiolo]

@@NoelsRetroLab I was mistaken about the bake process effecting the wire bond. The bake is meant to address migration of matter within the IC that constitutes components on the chip. Adrian (of Adrian's Digital Basement) did an experimental run on a few of his dead chips and met with some limited success. The video date was Dec 5, 2020.

[@david8804]

Este canal se merece muchos, muchos más subscriptores. Un 10 Noel! Saludos desde Barcelona. Por cierto una pregunta por curiosidad... eres español? Es que en algunos sitios del vídeo como que aparecía texto en español y pues tenía curiosidad 😂😂

[@NoelsRetroLab]

Gracias! Sí, vivo en Asturias o sea que casi todos los productos que uso están en español 😃

[@danmorgan4934]

Since most of the rust was more towards the rear of the board, I don't think it's from the traces on the bottom side of the board at all. I think the spots of rust are deposits from the portion on the R/F shield the rear underside of the C64, the board was sat on. Some WD40 / rust removal fluid and a soft cloth would of easily of removed the blotches without the need to go scraping at the traces and potentally damaging the PCB lacquer coating, which could then expose the copper traces and form points that could be shorted out once it was re-assembled.

[@basvanharen2904]

I recon Donkey Kong for SID testing😅 Some nice tips again for c64 repairing, thank you. What kind of work do you do for a living, something with electronics right?

[@NoelsRetroLab]

Thanks for the tip. That's the one Adrian uses for his dance parties, right? 😃 I studied Computer Systems Engineering. Electronics were not taught in a good way (for me) so I ended up focusing more on the software/firmware part. These days I do game development, so it's all software, and all the electronics I use here I just learned by myself in the last 5-8 years.

[@basvanharen2904]

@@NoelsRetroLab I like the structure of your troubleshooting, inspiring👍 Any familiair games we know you worked/working on?

[@MBDB666]

Yeah, if the Commando music is NOT ANNOYING, then the SID is bad! LOL

[@NoelsRetroLab]

🤣🤣🤣

[@user-pk7mb9is1e]

another exellent video!!!!!! we need more bad traces!!!!!!!!

[@hadessuk]

Consider using MDFourier if you want to (really) compare the different SID implementations. Might require you to write your own generator code though.

[@MrMaxeemum]

There are tonal differences between each original chip also due to the analogue circuitry in the chips. The main thing with replacements is that artefacts aren't added.

[@NoelsRetroLab]

Very interesting. I didn't know about that project, but that seems great. Thanks!

[@NoelsRetroLab]

That's right. I had read that. Any idea what causes those differences? Is it in minor differences in manufacturing, or was it due to different plants or different processes? It's amazing how complex the SID chip is.

[@MrMaxeemum]

@@NoelsRetroLab I believe it's due to the analogue circuitry on the chip, the process used was great for making transistors that turned on or off but not so good for making analogue circuits such as resistors / inductors or capacitors as it would highly depend on the doping level / penetration so the tolerances of those components varied quite a bit. Personally I find it hard to tell the difference between the 6581 and the 8580 (which used different filter circuitry to make them more consistent.) but some people can. I'm just happy with either so I can listen to my favourite Hubbard music.

[@catriona_drummond]

First time I see the meme-term "weird flex" being a literal weird flex. :)

[@NoelsRetroLab]

🤣🤣

[@gaborszabo6406]

Hello, i had same issue with my sid. Very noisy and low volume...

[@NoelsRetroLab]

Weird! I wonder what caused that. Some static discharge that damaged something?

[@Zeem4]

Those marks on the back of the board are just some kind of dirt that's very well stuck to the surface of the solder mask, it's not corrosion of the board or the tracks.

[@NoelsRetroLab]

I was assuming it was corrosion that had bloomed from a single spot, but you may be right. Although it's really weird for stuff like that to accumulate in the underside of the board. This whole C64 is a big mystery. I'd love to know it's true story of how it spent the last 30 years 😃

[@Zeem4]

​@@NoelsRetroLab It does look weird, but I've seen stuff with marks left by insect activity that looked quite similar to that.

[@GodmanchesterGoblin]

@@Zeem4Indeed. Insects and spiders often leave "evidence" like that.

[@austfox2170]

Sorry if it’s been mentioned in a previous video, but I am newish to your channel. What brand is the microscope you are using?

[@NoelsRetroLab]

No worries. I did a mini-review in this video. It's cheap, low quality, but still super useful (as you just saw). Definitely recommended. kzbin.info/www/bejne/hp-xgJaheMihaLc

[@austfox2170]

@@NoelsRetroLab Thanks for that. Just watched the video and I’ll be placing an order for one when I get home.

[@johnworsley7717]

Been waiting ages for this vid loved the 1st one thanks mate

[@NoelsRetroLab]

Ages, ages... the first one was two weeks ago 😃 But I'm really glad to hear it. Third (and final) part coming up in two weeks.

[@johnworsley7717]

@@NoelsRetroLab When youre a fan a day is ages! Haha!

[@WinrichNaujoks]

So the multimeter can be used to measure continuity. Is there a way to judge the quality of continuity though? A connection might give you a beep on the meter, but the resistance might be really high, meaning the connection isn't good enough. Any way of telling if that's the case?

[@NoelsRetroLab]

If you want that you can set it to straight resistance measurements (Ohms). But usually continuity is the same thing as resistance, it's just that it beeps if it's below a certain amount 3-4 Ohms probably. So if it beeps it's usually good enough. Sometimes you'll hear intermittent beeping which means the resistance is right at the threshold, so that might be worth investigating why (usually it's just some flux on the surface).

[@WinrichNaujoks]

@@NoelsRetroLab Very interesting. Thank you, Noel!

[@fcastellanos]

Viewing all the difficulties for repairing faulty Commodores 64's and the high prices that people's ask for them I'm restraining on buying any 64's although I'm in love with them from the mid-eighties. I can repair a humble Spectrum and even a 128 and Plus2 (grey, A/B), but without spare parts and a working parallel computer from where to borrow is very difficult. Also, there's the matter of the C64's faulty power source and the need to have a Dead Test cartridge, source protectors and so... All of this refrains me from buying a Commodore 64. I'm now with MSX also, fully aware that some of them are very crappy ad difficult to repair too, because of the bad quality motherboards which can be burned easily with the solder. I you have to charge something for this repair, surely the cost would not be paid enough. too many hours and too many work and components. Anyways, I'm learning a lot from your videos, because they often guide me to the most logical solutions, and I've repaired and/or upgrade some computers following your guidelines.

[@NoelsRetroLab]

I actually agree with you. C64 repairs can be quite challenging (but also the most fun) because so many different things can lead to a black screen result. It is a really fun system, so I'd encourage you to get a working one, and after that, having one where to test things, it helps a HUGE amount. The times I've worked on MSX repairs I found them pretty difficult because every machine is a little different, some don't even have public schematics (*cough* Toshiba *cough*), and then you always have the "MSX Engine" chip that controls just about everything and is different in every MSX. There also doesn't seem to be a common diagnostics program, which makes it even more difficult. At least I know that if I'm tackling a C64 (or Spectrum, or Amstrad CPC) I will be able to fix it. I've had to give us on a couple MSXs because I wasn't able to make any progress.

[@fcastellanos]

@@NoelsRetroLab You're right, and I said before, your opinions are very important to me. I like your channel a lot.

[@DylansPen]

Don't second guess yourself, every time you pick incorrectly you learn something. They aren't failures.

[@NoelsRetroLab]

About the sockets? Nah, that was just me being lazy. Those sockets should be burned on sight, especially if they have any signs of corrosion. But you're right, I did learn something 😃

[@gertsy2000]

Good video Noel. What about that case?

[@NoelsRetroLab]

That's part 3. Coming up in 2 weeks 😃

[@FernandoelChachi]

Me encantan tus vídeos arreglando Commodores ;)

[@francescosacco4969]

I like to see this type of repair. Good job.

[@NoelsRetroLab]

Thanks! 👍

[@blackterminal]

Thank you.

[@giuseppelavecchia775]

Un buon lavoro,sei geniale,un gran tecnico.grande il C64,ciao

[@NoelsRetroLab]

Grazie!

[@DAVIDGREGORYKERR]

There is already a replacement board that replaces all custom chips with one Mega FPGA called the COMMODORE C65

[@NoelsRetroLab]

But where's the fun in that?? 😃 Seriously, I prefer individual chip replacements. I really don't like those mega chips, even as the original manufacturers did back in the day (like with the ZX Spectrum +2 for example).

[@dorinxtg]

Noel, great video! small question through - where do you get those t-shirts? :)

[@NoelsRetroLab]

Haha, I actually print them myself for the most part 😃. For some of them I had to re-create the logos because I couldn't find them in high resolution. www.latostadora.com/retrocomputers/

[@bryanminugh9680]

at 17::40 I see that gold being covered over with solder..something the factory could >NOT DARE< to allow, because the lead soon turns black.

[@NoelsRetroLab]

But the solder mix stays shiny and conductive for many years under normal circumstances, right? Probably not as much as gold-plated materials, but I don't think it's going to go bad any time soon.

[@bryanminugh9680]

@@NoelsRetroLab