Time for a downgrade...
So those that have been reading this blog for a little while (yes I know who all 3 of you are) might remember that I bought a Commodore 128 back in 2014. What I don't think I mentioned at the time, was not only did I never previously own a Commodore 128 - I had never actually even touched one in the flesh.
It's been a fun machine to play with - but it doesn't have that same nostalgia that the Commodore 64 has for me personally. So this week I sold my Commodore 128 and bought a non-working Commodore 64 (working ones go for ALOT more).
So before plugging it in I opened it up (Dave Jones style) just to have a look.
Inside does not look like it's had anyone in there in a long time. No repairs or swaps that I can see. Bottom of the board has some bubbling of the silk screen - seems quite common for these boards.
I got out my ESR and checked the caps - they are all within range but I've ordered replacements anyways given I only need 6 of them.
Once all that was done I plugged in my Ray Carlsen power supply that I bought for the c128 (I sold it without the supply), my Hercules Workshop video cable that gives me S-Video out and hoped for the best. As the ad said when I bought it - nothing. Just a black screen. For those that don't remember, the black screen on a c64 is akin to the Red Ring of Death on an Xbox.
Consensus is that this is most often caused by a faulty PLA chip (these run quite hot normally and are not heatsinked so have a high failure rate). I've ordered a replacement that will take a while to get here (so I didn't pay more than what I did for the C64 itself).
I've also ordered a set of sockets - as you'll notice most of the ICs are not socketed. Any I replace I will socket when I do so. I've also ordered a set of heatsinks. I checked the 5 and 12 volt rails on the board and they are both fine. None of the other chips got hot (I didn't leave it running forever). Most people say that if a memory chip gets hot its probably shorted.
I have a diagnostic cart - but that doesn't work either. Same black screen when I use it.
So I'll wait patiently for a couple of weeks for the bits to turn up that will hopefully (with a bit of luck) bring this guy back to life!
It's been a fun machine to play with - but it doesn't have that same nostalgia that the Commodore 64 has for me personally. So this week I sold my Commodore 128 and bought a non-working Commodore 64 (working ones go for ALOT more).
So before plugging it in I opened it up (Dave Jones style) just to have a look.
Inside does not look like it's had anyone in there in a long time. No repairs or swaps that I can see. Bottom of the board has some bubbling of the silk screen - seems quite common for these boards.
I got out my ESR and checked the caps - they are all within range but I've ordered replacements anyways given I only need 6 of them.
Once all that was done I plugged in my Ray Carlsen power supply that I bought for the c128 (I sold it without the supply), my Hercules Workshop video cable that gives me S-Video out and hoped for the best. As the ad said when I bought it - nothing. Just a black screen. For those that don't remember, the black screen on a c64 is akin to the Red Ring of Death on an Xbox.
Consensus is that this is most often caused by a faulty PLA chip (these run quite hot normally and are not heatsinked so have a high failure rate). I've ordered a replacement that will take a while to get here (so I didn't pay more than what I did for the C64 itself).
I've also ordered a set of sockets - as you'll notice most of the ICs are not socketed. Any I replace I will socket when I do so. I've also ordered a set of heatsinks. I checked the 5 and 12 volt rails on the board and they are both fine. None of the other chips got hot (I didn't leave it running forever). Most people say that if a memory chip gets hot its probably shorted.
I have a diagnostic cart - but that doesn't work either. Same black screen when I use it.
So I'll wait patiently for a couple of weeks for the bits to turn up that will hopefully (with a bit of luck) bring this guy back to life!
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