CommodoreZ
Experienced Member
Way back in 2009, a younger, less experience me took a crack at fixing a certain Commodore 64 in my collection.
It arrived via a kindly couple who spotted it on a walk through the neighborhood and knew I would like it -- too bad it was broken. I had just fried my main C64 pretty severely, so I tried my hand at fixing the new arrival. OUT OF MEMORY IN 0 was all I could see on the screen, and I was told that the RAM was the likely culprit. I desoldered all 8 chips, and installed sockets and fresh DRAM. No dice, just colorful garbage. Needless to say, after some time I got disheartened and gave up. Other C64's filled the void for many years, and one additional half-hearted attempt was made maybe 2 years go.
Last month I finally took another crack at the problem with fresh enthusiasm, tools, and know-how. Oh, and significantly more soldering practice under my belt. Colorful garbage was still visible, nothing more. I suspected the 7708/74LS257 chips leading to the RAM might also be bad, so the first thing I did was remove them then add sockets and fresh chips. I then checked over the traces to see if anything critical was damaged. Sure enough, my poor teenage soldering skills hadn't properly soldered in a few pins here and there. CAS, RAS, lines in particular, as well as a ground/VCC line or two. There were also 3 additional damaged traces I had missed the first time around, so some bodge-wire was in order.
After a bit of testing, the colorful garbage changing in meaningful ways, this battered old C64 was running again! It needed a few heat sinks to ensure the life of some of the more troublesome chips. Oh, and a tiny little 5V fan for the VIC-II (which I have yet to fix in place). That bit may or may not stay.
Within a day of the RAM issues being fixed, the PLA gave up the ghost. No matter, I had a spare I harvested from the other machine. Once that was swapped in, we were in business!
Did I mention that I did a bit of customization? I painted a spare case red back in 2007, then swapped in the keyboard from my C64C for kicks.
Anyway, to those who helped out the bewildered teenager asking for help all those years ago, thank you. It only took me a few years to get around to fixing this Commodore machine.
It arrived via a kindly couple who spotted it on a walk through the neighborhood and knew I would like it -- too bad it was broken. I had just fried my main C64 pretty severely, so I tried my hand at fixing the new arrival. OUT OF MEMORY IN 0 was all I could see on the screen, and I was told that the RAM was the likely culprit. I desoldered all 8 chips, and installed sockets and fresh DRAM. No dice, just colorful garbage. Needless to say, after some time I got disheartened and gave up. Other C64's filled the void for many years, and one additional half-hearted attempt was made maybe 2 years go.
Last month I finally took another crack at the problem with fresh enthusiasm, tools, and know-how. Oh, and significantly more soldering practice under my belt. Colorful garbage was still visible, nothing more. I suspected the 7708/74LS257 chips leading to the RAM might also be bad, so the first thing I did was remove them then add sockets and fresh chips. I then checked over the traces to see if anything critical was damaged. Sure enough, my poor teenage soldering skills hadn't properly soldered in a few pins here and there. CAS, RAS, lines in particular, as well as a ground/VCC line or two. There were also 3 additional damaged traces I had missed the first time around, so some bodge-wire was in order.
After a bit of testing, the colorful garbage changing in meaningful ways, this battered old C64 was running again! It needed a few heat sinks to ensure the life of some of the more troublesome chips. Oh, and a tiny little 5V fan for the VIC-II (which I have yet to fix in place). That bit may or may not stay.
Within a day of the RAM issues being fixed, the PLA gave up the ghost. No matter, I had a spare I harvested from the other machine. Once that was swapped in, we were in business!
Did I mention that I did a bit of customization? I painted a spare case red back in 2007, then swapped in the keyboard from my C64C for kicks.
Anyway, to those who helped out the bewildered teenager asking for help all those years ago, thank you. It only took me a few years to get around to fixing this Commodore machine.
