Paul,
If I may impose on your knowledge of PSUs, can you help me with an earlier
post?

I have a Acer Verition M460 [AMI BIOS R01-C3] with WindowsXP SP3.
I had the CMOS set to wake and boot every morning. Worked fine for several
years.
Then intermittent, now not at all.
In the morning the power light is on and the NIC light is sometimes on.
Screen has no info and the PC has stopped short of actually booting [so
Event Viewer has no info]. I simply hold the power button 3 seconds and
repower up. Always successful.
Time/date is accurate but I changed the CMOS battery and re-enabled the RTC
alarm.
I also changed the PSU.
No joy.
Obviously not a major issue but I am curious, any idea why this is
happening?
Thank you.






"Paul" wrote in message
...
mynick wrote:


thanks for great explanation
so in modern mobos the on switch grounds a pulled up line, straight to
southbridge
(Possibly there is a Schmitt trigger/inverter in between the two)

+5VSB +5VSB
| |
Pullup Pullup
Resistor Resistor
| PS_ON# |
PWR X----+---- Motherboard logic ---- Open -------------------+- ...
Collector (to
GND X----+ Driver ATX +
| supply) |
(Front GMD GND
Panel
Switch)

Using an ohmmeter, between PWR and PS_ON#, doesn't tell you anything.
There is a silicon chip in the way.

Paul