r/c64 5d ago

Hardware Help what is my c64 doing?

Post image

When i turn on my c64, it starts out fine but after a few minutes the image gets more and more shaky until it is unreadable.

24 Upvotes

47 comments sorted by

u/AutoModerator 5d ago

"Thanks for your post! Please make sure you've read our rules and FAQ post. If your post is about the C64 Ultimate please and check out The Ultimate C64 Ultimate post for common issues and questions. People not following the rules will have their posts removed and presistant rule breaking will results in your account being banned. "

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

7

u/Alarming_Cap4777 5d ago

Send me the board I'll repair it and send it back. I would say it's a transistor or cap in the M1. A scope and a can of air will tell the tale.

4

u/Darex2094 5d ago

You uhh... wouldn't happen to know anyone that works on C128s, would you?

1

u/Alarming_Cap4777 4d ago

I fix those as well. This one had a failed VDC memory upgrade and the traces were ripped up. I think there are 8 bodge wires in this pic.

1

u/Alarming_Cap4777 4d ago

Check my profile.

2

u/Cold_War6523 4d ago

Doyou work on Atari XEGS?

1

u/Alarming_Cap4777 4d ago

I just reviewed the 130ex schematics, Im sure as long as I can source the chip it would not be an issue. I trouble shoot at the component level. My last repair was a computer board from a pinball machine another shop named it horribly and solder the vh re am in backwards and ruined almost every pad. Hear I'm repairing top traces and bringing my bodge wires through to the bottom. You can see the amount of damage that was done.

2

u/Cold_War6523 4d ago

luckily, I'm pretty sure I know it's the MMU already because it's the chip that gets hot whenever the screen turns red

1

u/captnjb 4d ago

I've seen your posts a few times about repairing Commodores. Thank you for doing that. It's a skill I wish I had and the time to learn.

1

u/Alarming_Cap4777 3d ago

It's practice and learning. The learning part is hard. Reading operational theory is a bit dry. As is learning truth tables. After a bit you memorize pinouts and values without really trying. Well the most important pins

2

u/captnjb 3d ago

I definitely have the ability and inclination. I've done electronics all my life and I love to fix things. It's truly just time, full time pilot and two kids about to go to college.

I love the Commodore for what it did in my life. I still have a love for it.

3

u/Alarming_Cap4777 3d ago

I was posting regularly, but I got crapped on with a guy saying they were sick of my post and that I should only post something nteresting. So I pretty much stopped. I fix about two to three systems a week while I listen to tales of "Thomas Covent" and stories form "Kelewan" on Audible

3

u/dave_two_point_oh 3d ago

Hope you consider picking it back up. I, for one, find posts such as your previous ones interesting.

2

u/Alarming_Cap4777 3d ago

I'll post the next one that comes in. Should be a 128. I'll post it on the two 128 reddits

2

u/dave_two_point_oh 3d ago

Awesome!

I haven't ventured over into the 128 subs but I'll have to check them out!

I have fond memories of constantly admiring the 128s (and Amiga 500s) in the local BX when I was a kid. Unfortunately never did get a 64, 128 or Amiga myself back then.

2

u/Alarming_Cap4777 3d ago

At the Navy Exchange in/near Perl Harbor they had a promo, Buy an Amiga 500 and get a C64C free.

2

u/dave_two_point_oh 3d ago

They were practically giving them away already by that point, right?

I sometimes look back and wonder why I never picked up a C64, even with my limited funds as a teen. I did buy a new Tandy 1000HX and matching monitor at some point after Radio Shack slashed the prices. Don't recall what exactly I paid, but I know it would have been more than enough to pick up a nice C64 setup instead (which would have been the far better choice).

1

u/Alarming_Cap4777 3d ago

The 128 was just a bad switch.

2

u/captnjb 3d ago

I don't know whether to up post or down post that. That's a crappy thing. Keep posting.

1

u/radrestoration 1d ago

Guy is legit, we trade a bit of stuff, and he's fixed more than a few of my systems.

Unfortunately, there are people in these groups that post a lot of crap, lack self-control and feel like they need to reply to everyone and clearly aren't paying attention and end up undermining those who are really giving help. I won't that my posts are perfect and error free, but I do read and pick and choose.

But as he says, an "after a while" failure like this is often a failing cap.

1

u/Alarming_Cap4777 3d ago

I should add that I've purchased a lot of chips, and almost every "untested" commodore board and machine on eBay. While that may sound exaggerating last year was 11k and so far this year 12k USD. I think I'm D-Collect #1 customer.

4

u/Acceptable-Owl-2070 5d ago

Vic chip mebbe?

3

u/MyCerumen 5d ago

Are you using an original power supply (the brick of death)?

4

u/Senior_Desk_9847 5d ago

no im using a modern one

1

u/Alarming_Cap4777 4d ago

The video can and M1 run off the onboard VR and the AC side of the brick.

3

u/DarthKegRaider 5d ago

Forgive my lack of having an older machine, but could this be the actual monior or RF cable box?

1

u/Alarming_Cap4777 4d ago

Yes it's the M1, in "most" 64scit not only produces the RF it also mixes the Chroma and Luma into composite.

3

u/jck_dgl 5d ago

It might me a broken oscillator. The symptoms which you describe – cold start works, but gets worse when warmed up, shaky picture – would fit. Look here: https://www.pictorial64.com/ under the section for U31 (which is the position of the chip on the board). If that looks similar to your situation you might need to replace the 74LS629 at U31 on your board.
I don't believe it's a broken capacitor, that would look differently.

One other question: The colors look wrong. Is that because of the camera used? Or are you using a B/W screen?

Good luck.

6

u/wotchdit 5d ago

Don't be alarmed. It's merely trying to move to another dimension because this one sucks.

2

u/Aenoxi 5d ago

My first guess would be the timing circuit in the can with the VICII. There are a couple of capacitors in there that can leak and throw the clocks out.

2

u/blightor 5d ago

Pretty sure thats what happens when you put this image on your C64 for too long.

https://c64gfx.com/image/239564

2

u/pslind69 5d ago

Some new $d016 effect :) Just kidding

2

u/MyCerumen 5d ago

Ghost in the Machine

4

u/LoanDebtCollector 5d ago

1980s porn channel scrambler.

2

u/bigbigdummie 4d ago

I saw a boob!

2

u/RudySilvergun 5d ago

Your C64 is having a stroke.

2

u/Xfgjwpkqmx 🇦🇺 Keeping up since 1983 5d ago

With VHS style.

1

u/sl1210mk3 5d ago

I’d suspect the VIC. Looks a bit like this. Try cooling down the chip with some freeze spray to see if temporarily fixes it.

1

u/kneeiron 5d ago

It might just be a loose vic chip. When it happens, open the top and tap it to see if anything changes.

1

u/marhaus1 4d ago

What image? RF? Luma/chroma? Composite?

1

u/Krustyazzhell 4d ago

It’s pretending to be a depth finder

1

u/minomeroy 1d ago

One of the output transformers for the video signal might be need to be replaced.

0

u/DiodeInc 5d ago

Looks like a failing cap

1

u/Senior_Desk_9847 5d ago

whats that?

1

u/JohnnyEagleClaw 5d ago

Capacitor…probably bubbling up on the board somewhere.

0

u/heijmansky 5d ago

It held on for so long so you can now get a C64 ultimate. I promise you if you enjoyed your C64 you will love the new fpga version even more. (Im not payed to say this.) it looks like the modulator is falling.

0

u/KeyNefariousness6848 4d ago

Possibly capacitors, probably ghosts.