25 Nov
1999
25 Nov
'99
3:06 p.m.
Will Jennings wrote:
[snip]
I also have all the schematics, software,
etc. for the Nova 1210. However, I need help with mine... I plugged it in
after reassembly and it works, but I quickly turned the key to off and
unplugged it cuz I noticed smoke coming from one of the capacitors on the
back of the backplane.. I either plugged the power connectors in backwards
or the supply is faulty, any ideas on how to diagnose this? I have the
schematics but they show a totally different supply than what is in the
machine...
I'm not sure what power connectors you might have plugged in backwards;
the 1200 and the 800 use the same form factor power supplies which
used edge connectors to mate with resistor boards. You also said the thing
worked before some cap on the backplane started smoking; I'd personally
suspect the cap in question.
There were two different power supplies used in the 800/1200, a "dual +5"
supply and the "plain old" 800/1200 supply. The easiest way to tell the
difference is to look at what's feeding pin one of U1; if it comes off
of a 1N5225 it's a dual +5 supply; if it comes off a 2N4400 which in turn
is fed by a 1N5248 it's the "plain old" version.
Of course it's been a while since I've looked closely at a 1220...
Best,
Chris
--
Chris Kennedy
chris(a)mainecoon.com
http://www.mainecoon.com
PGP fingerprint: 4E99 10B6 7253 B048 6685 6CBC 55E1 20A3 108D AB97