14 Jul
2006
14 Jul
'06
4:57 a.m.
I know almost nothing about these machines - are there
any particular gotchas
about restoring them (like, "don't touch this bit as all the paint will fall
off") other than the usual stuff that applies to bringing up a new toy for the
first time?
The logic board *looks* healthy enough - it seems to have escaped the
corrosion that's got bits of the case. Isn't there a particular chip (or
several) that's prone to dying in PETs though? Remains to be seen if it'll
power up.
I've repaired a number of PETs in recent years, including a couple of the
original 2001 machines like this.
Physical failures are common in the PET - look for corroded sockets,
video, power connectors etc. Be careful with the wires to the keyboard,
as these break easily (although this would not result in the dead-system
that you are observing).
The most common chip failures I enountered were RAMs (several)
and ROMs (two cases). If you check my site, you can see the interior
shot of one of my 2001s where I had to build a little daughter board
to adapt a 2716 EPROM to fit into the original ROM socket. Another
2001 that I have has a rom upgrade board which carries a set of
ROMs for version 4.0 BASIC. I believe the original ROM content is
available on funet - If everything else seems to be OK, you might
try reading the ROMs and checking the content.
I also had one instance of a failure in an I/O chip - I don't recall
if it was a 6521 or 6522 but it was one or the other (and this was
in a 2001).
Regards,
Dave
--
dave06a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.classiccmp.org/dunfield/index.html