15 Apr
2013
15 Apr
'13
6:11 a.m.
On 04/14/2013 09:23 PM, David Riley wrote:
Yes, should do - although I'm leaning toward just faking it for a simple
test. Connect up ATX PSU so that the Apple has +5V standby, then hit power
switch on the Apple, then hook the PSU's PS_ON line to ground to turn the
supply on.
I'll definitely be looking at fixing the Apple's PSU fault though if it
seems that the system board is alive (this era of Apple isn't really my
thing, but OTOH vintage computers of any description are almost impossible
to find here, so it doesn't feel right to give up on it!). Although, maybe
I should look at home much a keyboard's going to cost me first... :-)
Oh, having pulled the sub-woofer out, there's some rust on the chassis
beneath; it makes me wonder if the machine got wet at some point and that
killed it (with the battery corrosion coming later).
cheers
Jules
Unfortunately,
it's also confirmed that I've got a dead PSU; I've got
no +5V on the standby/TRKL line at all. I've done a few basic checks
for open diodes, transistors etc. on the AC input side, and things
seem OK there.
I think I have a spare ATX PSU from a PC somewhere, so I may try that
if I can contrive something to marry up the different power-on signal
(or I suppose I could just hit the power switch on the back of the
Apple and then turn the PSU on manually, just for testing purposes) -
there's probably no point my spending time fixing the Apple's PSU if
the system board is toast anyway...
A simple open-collector inverter made from a general-purpose NPN
transistor should do fine.