Commodore 64 Black Screen issue...

[alexjames01]

I just picked up a C64 when I went to hook it up to my TV, i just got a black screen. It is feeding a signal because it goes from snowy -> black screen when i power it on.

I did notice my power supply is missing the third prong on the plug. This is only for grounding though, am i right? Shouldn't it still work without it? or is this something that I should try and repair as a possible cause?

Also, how bright are the power LED lights on these things? Mine lights up but seems somewhat dim. Could it be dim from a failing power supply, or are they usually somewhat dim at this age?

[OmegaMaximum]

First off, I would test the power supply, just use a multimeter and check to see if the values you're getting match the rated values on the power supply. To me it certainly sounds like a dying power supply. Also, are you using the standard Commodore 64 A/V connector or a simple RF connector? If you can, perhaps try another A/V connection to rule out a possible shortage in one of the connectors. As for the 3rd prong, yes that's for grounding, and it should work fine with out it but you need to get that fixed, it's grounded for a reason. As with the LED, that also seems to be another indication that it's not getting enough power, as I've never seen an LED dim with the proper amount of power, unless it's dirty. Hope this helps you, I've been meaning to get out my C64, it could use some cleaning and testing again.

[CRTGAMER]

Power plug will still work without the ground pin, but not a good idea. You could lop the end off and put on a proper three prong plug.

The "AV" RCA connector is really a RF connection. Get a RCA to Coaxial adaptor. Better yet, get a Commodore cable that plugs in that large Din plug in the back. One is for the disk drive, the other is for audio and video.

[alexjames01]

Think i might have to make my own power supply. I am pretty sure now that is the issue. I turned it on earlier and it worked just fine- then the light faded and seemed to lose power. Haven't been able to test it properly just yet.

Reading up on it, it looks like these things have faulty power supplies to begin with. I haven't found a real upgraded solution online. It's hard enough to find a working original.

I kind of suck at soldering (well, i've only tried twice). Anyone know how hard it would be to make my own power supply for this thing?

[jeffro11]

Take the power supply apart. You may be able to fix it. It could be a few things gone wrong inside of it. Take it apart and check it out! Discharge the capacitors before touching them though!

[Hatta]

The best thing to do is get a C128 power supply and splice on the C64 end. You could pick up a new DIN connector so you have all the pins.

The C64 power supply is a little tricky, since you need both 5VDC and 9VAC. You might be able to get by with a 5VDC source and an NES wall wart which provide 9VAC. Not pretty, but it should work.

If you have some electronics experience you can make 9VAC out of 12VDC, which you can get from an ATX power supply. I don't have a schematic though.

[SnowKitty]

Take the power supply apart. You may be able to fix it. It could be a few things gone wrong inside of it. Take it apart and check it out! Discharge the capacitors before touching them though!

not gonna happen. c64 psus are potted in epoxy.

[alexjames01]

Well i cleaned up the system and all the connectors are nice and shiny. Got it to power up completely now and it seems to have stable power. It might have been a dirty connection.

My problems aren't over however. Now i have some garbage on the left side of the screen:



(ignore thick horizontal lines as that is just from taking a shot of an old tv monitor).

Those thin lines on the left get progressively worse the longer i keep it on. It spreads slowly from left to right taking over the text and turning that into garbage as well.

I am positive it is not a problem with the connecting cable because i have multiples and have tried on multiple tv's all with the same result. The sound works great too.

Could it be one of the chips needs replacing inside the c64? Luckily mine are socketed if so, and i wont have to use my horrible soldering skills if that is the case.

[CRTGAMER]

It Lives!

I am awed by your determination to get an old Retro Computer up and running. Great to see you have it working! Did you pop the cover and dust it out? Considering there is no fan, the inside should be clean, but can't hurt to look in there. Maybe a bug or two, real ones from the computer sitting so long.

You should be able to load a game and play, even with the lines on the left. Maybe in the game screen they may not show.

[alexjames01]

It Lives!

I am awed by your determination to get an old Retro Computer up and running. Great to see you have it working! Did you pop the cover and dust it out? Considering there is no fan, the inside should be clean, but can't hurt to look in there. Maybe a bug or two, real ones from the computer sitting so long.

You should be able to load a game and play, even with the lines on the left. Maybe in the game screen they may not show.

You'd be surprised... I went out today and got an old Sony Triniton TV just to use for the c64:



I think i found the culprit to my problem above as well! I did open it up to clean it and I also tested out how snug the chips were. I found that if i pushed on the Character ROM chip the lines would either go away (with a little pressure) or get much worse (with "a lot" of pressure). I took the chip out and cleaned its connectors as well as the socket and it did get somewhat better for a minute. Looks like it's time to replace this chip however.

Only problem is that the only place i can find them in stock is ebay and they are going for $20 - $40 each. I found this site that sells them for $1.99 plus some other c64 chips i'd like to buy for cheap: http://www.arcadecomponents.com/catalog ... 582500.htm but of course they are out of stock

Aren't you able to buy these chips and program them yourself with some sort of hardware? Wonder if that is an option?