Commodore 64 Black Screen Triple Challenge (Part 3 and Final!)

[@craftsman123456]

Another great video. I love how you show the scope and chip pin out on the screen at the same time

[@NoelsRetroLab]

Thanks! Yes, I'm trying to make it as approachable as possible, and hopefully some people will be encouraged to try to do similar repairs themselves. It's not rocket science! :-)

[@MoreFunMakingIt]

Hey Noel! This 3 parter popped up on my recommended list today (I had been watching ZX Spectrum restoration vids) and I wanted to say how much I really enjoyed these. It was like watching a whodunnit mystery! Great channel, looking forward to catching up with what I've missed!

[@NoelsRetroLab]

Awesome, thank you! Glad you're enjoying them.

[@safatkhan676]

I like how you do your troubleshooting videos. I just wish you fixed 50 more such C64s so that we could learn more possible failures and fixes. :D

[@auser6645]

I’m enjoying these videos. And keeping these old 8 bits going is a really worthwhile thing to be doing.

[@royloveday4350]

I don't know how I'll use this info, but it transports me back to O/A level technology, staring cluelessly at the insides of my childhood 8 bit micro, seeing basic info on architecture in Input magazine, self teaching myself Z80 machine code and never having much access to the kind of resources that would have allowed me to really dive deeper into the whole how it works of everything. Fun times.

[@NoelsRetroLab]

Right! That sounds very similar to my own experience as a kid. I was this sponge trying to learn all I could but resources were severely missing.

[@moshly64]

If the PLA is faulty and its enabling the kernal rom all the time or it is always being selected along with one or more chips then they will all get hotter as they fight to death on the data bus.

[@NoelsRetroLab]

That makes sense. I wonder why the kernal ROM is the one that seems to be stuck selected all the time. I might look into the ROM-selecting logic. Thanks for the tip.

[@SimonEllwood]

Maybe test the ROM once you remove it to find out if it is faulty or just getting hot as a result of bus contention.

[@FirstNameLastName-tp5bu]

Your videos are very well put together and, I really appreciate the way you teach while walking us through the troubleshooting process. You deserve a lot more subscribers. Keep up the good work!

[@NoelsRetroLab]

I appreciate that!

[@cailinwalsh705]

Hi Noel :) Not sure if you saw my Tweet on Twitter but I've recently fallen down the retro rabbit hole recently myself so I was pleasantly surprised to find your channel recommended to me on KZbin the other day! Also, maybe you have your reasons, but I felt I should point out that you would get much more "well formed" square waveforms on your oscilloscope if you set your probes to 10x mode.

[@NoelsRetroLab]

Hey Colin! No, I must have missed that :-) Glad you're also into it though. I didn't know the probes on 10x mode would make much of a difference at the range I'm working at, but I'll investigate. Thanks for the tip.

[@wegi9621]

Great advice !

[@tharkthax3960]

Enjoyed all 3 videos in a row. Your very clear and concise. Thankyou again.

[@NoelsRetroLab]

Glad you like them! Thanks for the feedback! I have several C64s that are piling up here, so I should have some more repairs coming soon. Happy new year!

[@AlenMarkov]

Absolutely LOVE this stuff - another great job. Thanks again for sharing Noel!

[@NoelsRetroLab]

You're welcome. Glad you liked it!

[@Miidolf]

Oh i just noticed the 6569 VIC-II chip so this machine is an PAL version. It was great to watch you figuring out the problems on this board. I would have enjoyed an small gaming session included so one can see if the machine works 100% (the joystick ports for one).

[@svenpetersen1965]

Nice. C64 repair videos are my favorites on youtube. The SID is the chip, that I have seen failing the most. I think, it was broken in about 25% of my C64s. Usually, I replace it with an ARMSID.

[@NoelsRetroLab]

For me it has been mostly PLAs but this is my first failing SID! I wonder if it depends on where they were manufactured. I'll have to look into the ARMSID though. Thanks for the tip.

[@tomasgabrielrojas7808]

I should add that SID chips (6581) have a tendency to show faulty filters if they are stored outside a motherboard or antistatic package. When i had to replace a dead SID in my C64 i found many of them at local electronic stores that worked partially because of that... I have now around 60 SIDs that i collected and verified them with benchmark tests on a real C64, they are stored in antistatic tubes waiting to be used on future fixes or upcoming SID related projects.

[@StatusFIX]

when ever i feel annoyed with electronics ,put some noel on in the background , works a treat

[@erikodh4338]

Amazing! I have many, many, videos how to fix a black screen c64. Mostly they change chips, with good ideas and intentions but you go from the basics and checks address and the data lines and really give to the bottom of the problem, I love that! Gave me a lot of ideas for checking my 3, yes 3, faulty c64's. Thank you

[@NoelsRetroLab]

Thank you so much! I really want people to feel they can tackle these kind of repairs themselves, so I love hearing that. Good luck with those repairs!

[@Flatwoodsdad]

Well this was certainly an info packed little series. Seems like removing the SID and re-seating as many chips as you can would be a good first step to try. But I think you got the boards the other guy's gave up on. Great series. Thanks

[@NoelsRetroLab]

Glad you enjoyed it!

[@mapax5]

Ibhad bumped into your channel here and there, but now I'm hooked. Looooove how you do your testing. Very methodical and detailed.

[@3vi1J]

Good stuff. I just discovered your channel and am really enjoying the content I've been binge-watching the last couple of days. Thanks for sharing your troubleshooting process!

[@NoelsRetroLab]

Thanks! Glad you enjoy it!

[@raymondheath7668]

Fortunately there is a good PLA and SID chip replacement on the market now which helps

[@David_Ladd]

Great video! Thank you for sharing the repairs! Always interesting to see which parts fail and how to go about fixing it.

[@davidinnes8554]

This helped with a board that had a fair bit of corrosion on it. SID removal now gets me the memory issue on the dead test cart. 3 ICs and a power switch so far. Thanks

[@NoelsRetroLab]

Great to hear!

[@drtadjakaroghli6898]

triple reto conseguido, ahora a por un Oric Atmos triple challenge achieved, now for an Oric Atmos

[@NoelsRetroLab]

Si alguien me manda un Oric estropeado, lo intento :-)

[@8BitRetroReFix]

Nice work . Ive watched all 3 :) .. Just one thing for you .. Always remove the sid before working on systems.. i do this every time mostly to save any damage . but they do cause the black screen and if you had you would have found it straight away :) ... Keep up the good work :)

[@TzOk]

Maybe ROM was getting unusually hot, because it had a short on its output (data bus)?

[@NoelsRetroLab]

It could be. That's the thing with electronics: everything is interconnected so it's hard to separate cause and consequence. It's odd that the other ROMs weren't getting as hot though.

[@alanclarke4646]

@@NoelsRetroLab Is the kernel ROM the only one accessed at boot? If so, maybe the other ROMs have their data pins in a high 8mpedance state?

[@aircraftmech123456]

I love your videos, removed SID and now i get an image everytime, suspect bad SID. what replacement do you recommend and where can I get it?

[@carnright]

Sounds cruel but seeing more complex issues being troubleshot is also interesting to watch 🙂

[@madmartigan1498]

Great videos, enjoyed all three of them. Would appreciate if you did some more C64 repair videos. Or c128... Got some dead boards around here, one of them fully socketed with working Chips, even the smaller ones, still wouldnt work. Think I‘ll carry on with my quest now... got some new ideas thanks to your video. Think there must be some faulty socket or a bad line. Try to figure it out the next days since Corona wouldnt let me leave our house... greets from Germany

[@NoelsRetroLab]

Thanks! I have another, more recent C64 video. Check that one out if you haven't. I'll make more videos as soon as I get my hands on faulty C64s. I don't have any in my backlog, so it's going to have to wait until the quarantine is over. But don't worry, I definitely will make more. The C64 is the most fun machine to repair :-)

[@djdublo]

All great stories come in trilogies! Fascinating videos. Never played with a C64, all my friends had Amstrad CPC like me!

[@NoelsRetroLab]

Glad you enjoyed it! I'm going to tell you a secret, just don't tell anyone: I never used a C64 back in the day either (!!!!!!!!!!!!!) 🤪😱

[@djdublo]

@@NoelsRetroLab 😄😄😄😄 that's so funny! Did have a couple of specify friends. My wife had a 48k spectrum until the keyboard wore out.

[@up2tech]

Hi Noel. I do enjoy your videos, although I didn't have any C64 on my youth (I got instead a +2 grey ZX Spectrum). Although I hated the color clash from the spectrum and only lately there is a way to insert 2-4 colors with an assembler script to avoid such thing, I do love the way the C64 displays colors. And for self-knowledge and curiosity sake, I got a video where it describes a small circuit to put on the cartdrige port on the C64 to check if there is a non-working PLA. The link: kzbin.info/www/bejne/pZfKZGawoJ6oeaM Time frame starts on 17':46" Thanks and keep up the good work you're doing :)

[@somosdeamstrad]

Great video Noel! Where one may find a PLA and SID chip for replacement?? I bought a faulty c64 last week. Still has not arrived but I am already preparing for the disaster! :-D

[@NoelsRetroLab]

Jgilcas makes some PLA replacements that aren't very expensive. Check with him. No idea about SID though :-(

[@Ikrananka]

If you're looking for a real SID then I've bought from an eBay seller in Hungary with success before. There are modern replacements, such as ARMSID (www.retrocomp.cz/eshop) which is excellent as it allows you to make all manner of adjustments to the filters as well as having both 6581 and 8580 modes.

[@timpsensky5181]

I use the PLAnkton, made by a fellow out of Canada. He sometimes has them listed on eBay. They are a very good replacement for the PLA and dont run hot. For the SID, i use the nano swinSID, but it is not 100% compatible as it doesn't have the analog support in for using paddles in the joystick ports. You can buy them on eBay also, but I make my own. Look on GitHub for the design. If you go this route, you also have to have a way to program them.

[@bikervikings8785]

i think the kernal got hot because it was figthing the PLA on the databus, could also explain why the voltage increase when you remove it, i think you can even kill chips if you keep it running whith a shorted output

[@NoelsRetroLab]

That makes sense, although I've seen the Kernal ROM consistently quite hot in several other C64s without faulty PLAs. It just seems to run hotter (more use?) and then the faulty PLA maybe pushes it over the edge.

[@Evhen_Velikiy]

Hmm... Think there is problem with IO chips too, because time did not counted during dead-test.

[@kamidphish]

I still have a dead C-64 here. I should send it you, so you can make another awesome diagnostic video on YT. :-)

[@NoelsRetroLab]

That would be a wee bit expensive I'm afraid. Maybe we need to do a Skype repair collaboration :-)

[@kamidphish]

Noel's Retro Lab I need one of those fancy scopes. :-) (yeah I just want all the toys for my man cave :-D)

[@ernstqueller]

Noel, love your videos, great troubleshooting and diagnosing skills. Where do you get your tee shirts? Love them

[@NoelsRetroLab]

Mostly I make them myself from logos that are either available or I recreate them 😃 www.latostadora.com/retrocomputers/

[@Mr_Meowingtons]

well lucky there is cheep replacements for the SID and PLA now...

[@NoelsRetroLab]

Cheap replacements for PLA for sure, SID... not so cheap. I'm working on an episode right now about modern SID replacements, so that should be interesting.

[@alexroman6246]

how about put voltage on databus with lab psu and look at thernal imager? its a bit expencive, but i think its really fast and interesting method in such cases)

[@davidrobinson9526]

It would be interesting if modern computers could be analyzed/fixed as well

[@NoelsRetroLab]

They can, but they require much more advanced tools and technology. That's one of the advantages of old tech, that it can be interfaced with and replaced much more easily given modern technology.

[@roberto660260]

Good video approved solution NOEL:):):):)

[@ingmarsretro]

great 👍