31 Jan
2012
31 Jan
'12
11:58 a.m.
I know following up your own request is kinda taboo=2C but I should have sh=
ared more information...
I am guessing that the problem is with the Color RAM (SRAM) in slot U6. Th=
is model of C64 has socketed components=2C but I am not sure U6 is one of t=
hese. The other possible issue is PLA U17.
As the problem never goes away=2C perhaps it is more than this.
Is there a good vendor to get replacements this late in the game?
IIRC some (all?) C64s use a 2114-type RAM for the colour information. If
that''s the case, change it. I've had more problem with that sort of chip
than any other component ;-). I've lost count of thew number of things
I've had to fix by replacign one or more 2114s.
If it's not socketed, don't worry. If your desodlering skills are not up
to much, then cut the pins off the old IC close to the package, remvoe
the packagem, and remove each pin separately. Grab the pin on the top
side of the board with a pair of fine pliers, melt the solder on the
other side and pull the pin out. Then clear out the holes using a solder
sucker from the top side while heatign the solde on the bottom side.
I'd ft ta socket. A turned pin (machined pin I think you call them)
socket. While a socket is less reliable than a soldered-in chip, I've
never hadn a problem from a turned pin socket (that is not true of
cheaper formed-pin sockets!), so I think it's sensible to fit one unless
there are good electrical reasons (such as stray capacitance) not to.
That doesnt' apply here.
-tony