Commodore 64 showing a black screen, can I fix it?

Рет қаралды 6,085

Күн бұрын

I was recently lucky to pick up this Commodore 64 from Woz who had offered it on RMCs discord for the low price of postage only. What's the catch? Well it doesn't work, its displaying a black screen only so lets try and figure out why? Will it just be the PLA (a common failure point for a black screen) or will it be something else?
CRG Twitter - / yt_crg
CRG Patreon - www.patreon.com/user?u=13919007
CRG Discord - / discord
Music - Cathode Ray Gun by @Momentvm
Chapters
00:00 Intro
00:20 Looking around the system
02:39 What's the symptoms
08:47 It has to be the PLA
10:42 Testing the VIC
11:32 Anything getting hot
12:45 Probing the MOS logic
15:23 Why is U15 not being enabled?
20:15 Replacing U15
21:06 Diagnostics
22:32 More problems?
23:07 Refinishing the edge connectors
24:44 Testing again
25:25 4066
26:22 Keyboard test
27:19 Loading a game
29:08 Conclusion and credits

Пікірлер: 59

@Chris-yc3mm 9 ай бұрын

Your enthusiasm is infectious when you cry "its working" 😊

@CRG 9 ай бұрын

I do tend to get a bit carried away 😅

@mogwaay 9 ай бұрын

You didn't just stumble on it, you totally figured out the problem! Nice work!

@CRG 8 ай бұрын

Thanks for the vote of confidence 🙂

@Snowcrash777 9 ай бұрын

Great troubleshoooting! I prefer the scope tracing and probing you do over the hit and miss repairs I've seen on most other channels. Not only is your content more informative but it also helps establish smart troubleshooting methods which seem to be lacking in too many repair videos. I have several of your tutorials book marked that are great! Your Xbench and PFS3 video was very helpful to me and I made sure I made my donation to the Xbench (And now SysInfo 4) programmer. Who happens to be a very nice person and deserves recognition and support for the excellent work. Thank you for sharing your repair adventures with everyone and Best Regards

@CRG 9 ай бұрын

Thanks for the kind words and the support, I've been guilty of just swapping stuff in the past but as you say it's better to try and understand the problem and that's what I tried to show in this video. Xbench and sysinfo are great bits of software and the developer absolutely deserves recognition and support!

@markwrightrf 9 ай бұрын

i enjoyed your guest appearance on this week's This Week in Retro. I love your enthusiasm when something just suddenly works. I'm reminded of Adrian Black and his catchphrase: "It's freekin' working!". Might I suggest "stand up you black and tans" for a successful C16 repairs and a C64 in desperate need of Retrobrite?

@CRG 9 ай бұрын

Thanks and welcome from TWiR. It was great fun to chat with the guys even if I was a bit nervous 😅. A C16 is one system missing from my collection. Not sure this one needs retro brightened but I'll know better once it's cleaned up.

@esc2dos 9 ай бұрын

Brilliant work Sir, really enjoyed your process to a solution, and I think you're convincing me that the SID chip is something I might need to compose with.

@CRG 9 ай бұрын

Thanks, the SID certainly is an iconic sound. If you do compose something for it please let me know.

@michaelcarey 9 ай бұрын

20:32 I fully understand the excitement of getting a dead Commodore 64 operational once more 🙂 It's a fantastic feeling.

@CRG 9 ай бұрын

It is great when they come to life, even if I do tend to get a bit carried away.

@Even-Steven 9 ай бұрын

It's always a good day when a c64 is saved.

@CRG 9 ай бұрын

It is very satisfying to see these old systems come back to life.

@johanpeturdam 9 ай бұрын

I do so love it when a Commodore 8-bit saved. Looking through your comments I hope you find a 128 for your collection. We had a 128 wedge (which needs fixing up) but I do remember always wanting a 128D. I’ll be crossing fingers for both of us. Btw., Kung Fu cartridge in the next video maybe?

@CRG 9 ай бұрын

Thanks, I'd love to get a 128, hopefully one day. Kung Fu flash will be coming soon.

@3vi1J 9 ай бұрын

Awesome as always CRG. Thanks for sharing this troubleshooting and expertise!

@CRG 9 ай бұрын

Thanks for watching and glad to hear you enjoyed it 😁

@miked4377 9 ай бұрын

i have come to like the phrase "its working!! its working!!!"good job glen !

@CRG 9 ай бұрын

Maybe I should get it printed on a t-shirt 😂. Seriously though, thanks for the support, it's greatly appreciated 😀.

@miked4377 9 ай бұрын

@@CRGthats a good idea!

@segasonic44 7 ай бұрын

Thank you for a very informative video. I have a 250425 board with the same symptoms and am suspecting the MOS 7711. Got a 74LS139 and socket on order, so hopefully my repair will also be a success (or at least let me continue and see if anything else is wrong).

@CRG 7 ай бұрын

Glad to year you enjoyed the video. Good luck with your repair, please let me know ow how it goes 🙂

@Plan-C 9 ай бұрын

Nice logical approach. I used to just shotgun chips 🤣 Nice music selection.

@CRG 9 ай бұрын

I've been guilty of shotgunning a few repairs in the past but tried with this one to properly figure out the problem and I think I got there.

@ddniUK 9 ай бұрын

Nice job! I need to get one of those power savers. My C64c never gets used for fear of the PSU going bang.

@CRG 9 ай бұрын

I think I got mine from Amibay although they are available from various places. But yeah I'm just waiting for one of the old PSUs to go bang.

@brynjarborgersen8131 9 ай бұрын

Why I give a thumbs up before I have even watched your videos? Now that's a conundrum for you, Glen ;) And now Ideally want to play with a 64 or 128......

@CRG 9 ай бұрын

Thanks, I appreciate the support. The 64 is such an iconic system, lots of great games on it. I'd love to get a 128, it's one of those holy grail systems, especially a 128D.

@scriptguru8 Ай бұрын

Great job! Thanks for the very informative video!

@SonicBoone56 8 ай бұрын

Made those edge connectors look amazing.

@ancipital 4 ай бұрын

Thanks - got a c64 to repeair that is doing a black screen - it was electrocuted 37 years ago by one of commodores wonderful PSU's, you've given me some pointers to look at to work out where it's bad!

@wozbrown6581 9 ай бұрын

Top job! Well beyond my skills, so happy to see you got it working… and a what a great video 👍

@CRG 9 ай бұрын

Thanks, glad you enjoyed it. It may look complicated but everything I learnt about these repairs comes from watching and chatting to other creators. I always say if I can do it then anyone can and don't be afraid to have a go on something like the 64 which itself is fairly simple to work on.

@otis7359 9 ай бұрын

Nice and smooth repair! Do you have any plans for "newer" consoles repairs, like PS3 or Xbox?

@CRG 9 ай бұрын

Nothing planned at the minute, I mostly try to focus on the older hardware but I do own an original Xbox that needs a bit of work at some point.

@force4200 9 ай бұрын

Great episode like ever :)

@CRG 9 ай бұрын

Thanks, glad to hear you enjoyed it.

@Rick_Todd 9 ай бұрын

Nice One . Another Great Fix.

@CRG 9 ай бұрын

Thanks, it's always great when they come back to life 😁

@morantaylor 9 ай бұрын

I called it the moment the screen was black. Over the years I have had to replace a number of these MOS chips that causes the black screen.

@CRG 9 ай бұрын

Seems to be a very common failure point. I'll have to keep an eye on the other mos logic chip. I suppose it's only a matter of time before it fails as well.

@philippecaillot2510 7 ай бұрын

Bonjour, et merci pour cette vidéo, j'ai le même souci avec i/o qui reste a un niveau logique haut, le PLA a été remplacé ainsi que le 74LS139 par un 74HTC139 ....mais dans mon cas l'écran reste noir et l'entrée I/O reste bloquée a l'état haut, je ne sais pas trop ou chercher, pouvez vous me conseiller ? Merci

@tenminutetokyo2643 9 ай бұрын

BTW the 2 small film caps next to the main inductor are CDE part # 224MMR100K . $.50 USD each.

@CRG 9 ай бұрын

Thanks for the info 👍

@KAPTKipper 9 ай бұрын

I always pull the SID on a new test. SIDs are sensitive, dead ones can cause black screens and they are not needed to test a 64

@CRG 9 ай бұрын

Good idea to be honest. I did try to power the machine with the Sid out but it made no difference. Probably should have covered this in the video but will try to be more thorough next time 👍

@YogSothoth1969 9 ай бұрын

Great work!!! o7 🙂

@CRG 9 ай бұрын

Thanks Cmdr 😉. Out of interest have you tried starfield yet, looks great but I'm yet to buy it myself.

@YogSothoth1969 9 ай бұрын

@@CRG no, I did not try it yet 🙂I am in Elite Dangerous Odyssey which had an update recently, my Cmdr name is RORY MACNAB 😀

@bartekantoniewicz5005 2 ай бұрын

Your amazing

@Mind-your-own-beeswax 4 ай бұрын

What’s the SD card wotsit your using to load the games?

@CRG 4 ай бұрын

Its an SD2IEC. Essentially an emulator of the 1541 disk drive.

@fu1r4 9 ай бұрын

4.86 or 4.9, I don't think it make any difference 😀 It could be your probes that got a better contact the second time you measured ...

@CRG 9 ай бұрын

Haha, good point, although I'm sure the difference was made by the contact cleaner and it was probably spraying it into the switch. On the same PSU it's now reading 4.96.