21 Mar
2014
21 Mar
'14
2:11 p.m.
check the powersupply capacitors, and all othe capacitors. they can
short or have taken a completely wong value over the years. changing
them all is a good idea.
can somebody please expalin why I rarely see capacitor failure, for all I
work on machines a lot older than this Osborne?
More seriously, I ahve had capacitors fail, but not that many. I have
never had to re-cap an entire machine.
In this case I would, indeed, start by checkig nthe power supply outputs
-- votlage and ripple. If there is a problem, then I would find out what
it is. It might wwell be a capacitor, but I wouldn't change it until I
knew. It might also be a bad connection oxidised pins, etc), a failed IC
(bit-rot in an EPROM, RAM failur, etc). Or a dozen other htings.
My 'first rule of repair' is not to change anything until you know what
the problem is....
-tony