Author Topic: C64 not playing skate or die  (Read 1834 times)

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Offline Jan AudioTopic starter

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C64 not playing skate or die
« on: December 17, 2019, 01:58:39 pm »
Hi, my C64 wont load skate or die.
How do i find out what is wrong with my breadbin C64 ?
thanks
 

Offline phlegeton

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Re: C64 not playing skate or die
« Reply #1 on: December 17, 2019, 02:23:57 pm »
Can you give more info ? Like, do you load the game from tape, or floppy ? Did you get an error while loading the game ? Are there more games you cannot load / play ? Did you do any measurements, like measure the PSU output, or voltage rails ?
 

Offline Jan AudioTopic starter

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Re: C64 not playing skate or die
« Reply #2 on: December 17, 2019, 03:00:07 pm »
I load from SD card.
Many more games dont work.
I measured nothing, for the rest other games does work.
 

Offline phlegeton

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Re: C64 not playing skate or die
« Reply #3 on: December 17, 2019, 03:08:06 pm »
Some games may took a very long time to load. However if some games do not load, you may want to measure the PSU output etc (Does the C64 crash ?).
Are their any capacitors bad ?
Also, if the games are not original, that may be a problem as well.
Do you have a C64 dead test cartridge ? So you can check the RAM and other IC's as well ?

Maybe their is a problem with the video RAM. But if this is the case, most of the time, their are (weird) characters on the screen, or other signs something is wrong with the RAM chips.
 

Offline Jan AudioTopic starter

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Re: C64 not playing skate or die
« Reply #4 on: December 17, 2019, 03:12:36 pm »
I already replaced the PLA chip or something.
I think i need a  C64 dead test cartridge  thanks.

No weird characters in the blue screen, normal text.
 

Offline phlegeton

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Re: C64 not playing skate or die
« Reply #5 on: December 17, 2019, 03:23:22 pm »
If the PLA is bad, then the C64 gives a black screen for sure. And most of the time, when RAM chips are bad, the screen also stay's black. However sometimes bad RAM chips causes problems, which are visible on the screen (this also might occur when the multiplexer IC is bad. A dead test cartridge can be handy to have at hand :-) One trick I often use to check the RAM IC's, is to feel which are getting real hot, in comparison of other RAM IC's. This doesn't always work, but sometimes it just might point you in the right direction.  In this case it's hard to tell if there is a hardware problem, or that the games itself are the problem.
 

Offline phlegeton

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Re: C64 not playing skate or die
« Reply #6 on: December 17, 2019, 04:01:12 pm »
Yes.. It's best to consider the original PSU as a time bomb. If I have to use an original C64 PSU brick I always measure the 5V output, before plugging it into a C64 and even then...
 

Offline Jan AudioTopic starter

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Re: C64 not playing skate or die
« Reply #7 on: December 17, 2019, 04:09:55 pm »
Yes the PSU i should measure, if its good its good.
Else i need a replacement, only some games does work so its not that bad.
I hardly use this computer so it will die of not using it for sure.
 

Offline Alex Eisenhut

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Re: C64 not playing skate or die
« Reply #8 on: December 18, 2019, 12:51:41 pm »
Yes the original black brick power supply is very bad. The 5V fails and usually goes way up, something like 8V which as noted kills the RAM quickly.
A simple solution is to create an adapter so you can use a modern 5V switcher wall-wart and keep the 9VAC from the Commodore supply.
The 9VAC and 5V need to be isolated from each other in any case, and the Commodore's 9VAC winding almost never fails. I've never seen it in 30 years.

The Commodore supply's transformer is very good, it's the garbage regulator circuit and ridiculous potting that's the problem.
Hoarder of 8-bit Commodore relics and 1960s Tektronix 500-series stuff. Unconventional interior decorator.
 

Offline Jan AudioTopic starter

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Re: C64 not playing skate or die
« Reply #9 on: December 18, 2019, 01:10:16 pm »
I dont like using two power sockets, cant i build in a 7805 somehow ?
 

Offline phlegeton

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Re: C64 not playing skate or die
« Reply #10 on: December 18, 2019, 02:12:08 pm »
Building in a 7805 is tricky, like Alex Eisenhut says: ".. and ridiculous potting that's the problem" So adjusting an original C64 PSU is not easy, or almost impossible to do.

The C64 needs 9V AC, and 5V regulated DC. If you search the interwebs, you find a lot of solutions.
 


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