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C64 Black screen fault

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XDanger

Experienced Member
Joined
Oct 23, 2008
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76
Location
UK
I hadnt been able to get a picture from it, but after plugging in my amiga (which works fine) I noticed that also had a black screen
I re-tuned the tv and all was fine, gave the c64 another go after another re-tune and managed a boot up screen ,Joy was short lived as the keyboard did nothing so I turned her off and on and it was back to black again.

What fault would allow a seemingly one-off boot up display like this?

I've tried the c64 on my crt also and it was black so its not just an LCD TV related problem.
 
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Could be a bad connection that was momentarily good enough to get things working. I'd try reseating any socketed chips for starters - I recently had a similar problem which was solved just be reseating the kernal ROM.
 
http://www.commodore.ca/manuals/Tips/c64_tips.htm

Blank screen on power up----Should I be looking at these

Intermittent blank screen or graphics--- or these possible faults

Out of about 40 attempts ive only had 1 partial succes

Ive tried an alternate PSU (which I dont know if is good either but the power light comes on) but I also have a square black commodore supply, Whats that from, a vic20?

Like in my atari st thread ,I'll' definiltey try pulling the chip ,Thanks


C64 parts seem to be a rarity on ebay, Maybe easier to wait for another cheap (faulty) one and hope for the best.

The innards of newer c64 are the same arent they?
____________________________
If I ever get a working c64 can I wire the c2n plug to a 3.5mm jack for pc/mp3 loading?

I have 3 c2n's going spare atm :(
 
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XDanger said:
Out of about 40 attempts ive only had 1 partial succes
Click to expand...
That you got to see anything sensible on the screen, even just the once, would suggest that the parts are probably OK. Then again, maybe something just made an extra effort before giving up the ghost completely ;-)

XDanger said:
Ive tried an alternate PSU (which I dont know if is good either but the power light comes on) but I also have a square black commodore supply, Whats that from, a vic20?
Click to expand...
Power is always a good thing to check if you can (in fact I was going to suggest that if the reseating didn't help). The original C64 PSU isn't known for its reliability and there were numerous after market replacements - maybe you have one of those? Worth checking the right juice is coming out of the right pins before plugging it in though.

XDanger said:
C64 parts seem to be a rarity on ebay, Maybe easier to wait for another cheap (faulty) one and hope for the best.
Click to expand...
There are so many C64s floating around that it's often easier (and even cheaper) to pick up an entire machine and salvage what you need.

XDanger said:
The innards of newer c64 are the same arent they?
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Not really - there were quite a few revisions.
 
Just tried it again and got garble, Random charachters, different colors mostly @'s

cosam said:
Not really - there were quite a few revisions.
Click to expand...
I could just swap out the whole mobo though couldnt I?

Are the keyboard connection pins the same?

I like the brown.


Does the "International Soccer" cart replace any onboard parts like some carts do (i've read).
 
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Yes, the keyboard connector is identical in all VIC-20 and C64s. There was a report about the very first breadbox C64s having a different pinout but I think it was a mistake by the poster.

Autostarting game cartridges would not make any calls to Basic ROM, which is why some of them might work. If your Kernel ROM would be completely wasted, I don't think cartridges can start anyway since the 6502 (6510 more precisely) looks for an autostart vector at the end of Kernel ROM, and the routine the vector points to checks for a cartridge.
 
Last night I tried the cart and managed about 15 seconds of gameplay :)

Today I re-seated the only chip thats seated, I also gave the mobo a nice clean but still get black :(

Is the fuse wire supposed to be spiraled?

Back in the day my c64's fuse went and I used a paperclip in the meantime I think?

Maybe I'm thinking of the poke reset paperclippery.
 
I believe a fuse with a spiraled wire means it is a slow fuse as opposed to the fast ones. The C64 should have a slow one. A paperclip works fine as long as you're sure there is nothing wrong with your computer or power supply, e.g. the fuse blew because you touched some connector from the outside.
 
Troubleshooting 101:

Troubleshooting 101:

1. Insert paperclip in place of the fuse.

2. Turn on machine.

3. Observe board till MajikSmoke(tm) appears.

4. Replace all components which smoked (after turning off machine).

--T
 
Is that the smoke they put in there when its built and sometimes escapes?
 
Black screen... or blank screen and no keyboard response?

Bad CIA chip or bad PLA. My money is on the PLA.

You can swap the 2 CIA (6526) chips to see if it then boots but has other problems.

If the screen was full of @ symbols then it's a bad VIC-II chip...

If the screen has some, but not full of @ then you have bad RAM.

RJ
 
Its like @ @ @ @ @ @

@ @ @ @ @ @ @

Not @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 
Ram then ,Ah well, I guess that explains why it only likes cold boots

Pic?
garble.jpg

http://img22.imageshack.us/img22/6124/garble.jpg
I dont suppose theres a magical way of connecting one of those c64 tv joysticks to it to make it work is there ...
 
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There is no pic, just an ad for a picture hosting site. But i thinki can guess, it's just a black screen with a few @ on it?
 
damn aol selling off its pictures ,useless bunch of @@@@'s

No its pretty blues and colorful @'s and stuff
 
XDanger said:
Ram then ,Ah well, I guess that explains why it only likes cold boots

Pic?
garble.jpg

http://img22.imageshack.us/img22/6124/garble.jpg
I dont suppose theres a magical way of connecting one of those c64 tv joysticks to it to make it work is there ...
Click to expand...

You have a case of RAMitis there... ;)

The cure is a handful of 16 pin sockets and a few 4164 DRAM chips to swap out the bad ones.

Luckily those DRAMs are cheap.
 
So Id have to de-solder the ram and solder the slots in?

channelmaniac said:
You have a case of RAMitis there... ;)

The cure is a handful of 16 pin sockets and a few 4164 DRAM chips to swap out the bad ones.

Luckily those DRAMs are cheap.
Click to expand...

Where would I look for them in the UK?

The sockets I can get from RS but the ram not so much...
 
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