Found the extra C64 between the stuff for the upcoming flea market at the club. Suggested to have a look at it as it had a sticky note attached saying it was defective and "might be something simple"....
Some pics:
Opened both machines. My machine as you can see is "Made in England", the defective one in "W. Germany".
The defective one has a mobo from 1983, the working one from 1984.
Commodore made some improvements, they made a decent shield instead of some "aluminum foil" to shield the machine (like the Atari XL series had from the start). The funny thing is that apparently they had already discovered that the PLA and VIC chips were running too hot and parts of the shield are designed to touch the top of these chips. They put some silicon grease dabs (too thick) on those chips and so the shield also acted as a heatsink (where have I seen that concept of choosing cheap heat sink solutions again.........aha....yes the WG6100
)
Anyway, they also "improved" something else, they got rid of the sockets and soldered almost all but the most failing chips directly on the board. A well known practice that Jack Tramiel also brought with him to Atari. There he must have been extremely happy as none of the Atari 8 bit chips ran hot (despite it's 79% higher clock speed
) so he could solder them ALL to the board...sigh .....well it did reduce costs I guess.
Anyway, the PLA is getting hot but so is the SID. Swapped the PLA as that _IS_ socketed on both. The one of the "dead" unit made the working unit not work anymore, but regretfully it didn't work the other way around.
Conclusion, the PLA is dead, but there is more dead on that dead unit.
Too much dead for my time.....I closed the unit again and it'll go into the market for what it is: for parts or repair.
Just had a look at ebay prices for tested working C64 chips and they are pretty nuts, especially the SID !
However, I have no way to test that one or any of the others so....
Oh, you can see there is quite some differences in the casing, the German one is even higher than the English one (and I already thought the keyboard is wayyyyy to high on the C64 for comfy typing)....
If anyone wants this unit for parts or repair, make an offer, all the money goes to the marching band club
