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First post, by douglar

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I've got a ECS P5GX-M Micro ATX board.

The ATX power only stays on while the power switch jumper is shorted.

Is that normal? I mean, I have a latching switch that I could use, but it is sort of unexpected.

Reply 1 of 8, by Repo Man11

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It isn't normal. Have you tried testing it on a bench rather than in a case?

After watching many YouTube videos about older computer hardware, YouTube began recommending videos about trains - are they trying to tell me something?

Reply 2 of 8, by douglar

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Repo Man11 wrote on 2025-03-07, 02:48:

It isn't normal. Have you tried testing it on a bench rather than in a case?

Yes, works on the bench, as long as I jumper the power switch. I tried putting it in a case, but an SMD capacitor caught fire when I hitthe power switch. Board still works, even though it’s a little chared.

Reply 3 of 8, by dionb

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Repo Man11 wrote on 2025-03-07, 02:48:

It isn't normal.

Sure about that? I have an P5GX-M too and it shows exactly the same behaviour.

Reply 4 of 8, by Repo Man11

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dionb wrote on 2025-03-07, 11:18:
Repo Man11 wrote on 2025-03-07, 02:48:

It isn't normal.

Sure about that? I have an P5GX-M too and it shows exactly the same behaviour.

I stand corrected. What is the explanation? Is it a proprietary board issue? Perhaps a note should be added to the Retro Web if this is standard for this board? Are there other ATX boards that will not work properly with a standard momentary contact switch?

After watching many YouTube videos about older computer hardware, YouTube began recommending videos about trains - are they trying to tell me something?

Reply 5 of 8, by douglar

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Repo Man11 wrote on 2025-03-07, 12:11:

I stand corrected. What is the explanation? Is it a proprietary board issue? Perhaps a note should be added to the Retro Web if this is standard for this board? Are there other ATX boards that will not work properly with a standard momentary contact switch?

The note is added to the Retroweb description now.

I've seen some early Dell socket 5 boards that used latching switches, like this guy:
https://theretroweb.com/motherboards/s/dell-d … -p__c-minitower

Reply 6 of 8, by douglar

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So it's strange. It doesn't exactly need a latching switch.

Here's what it does:

  • When the power jumper is shorted, the power supply starts immediately.
  • If I leave the jumper shorted, it runs indefinitely
  • If I open the jumper in less than 3 seconds, the power shuts off.
  • If I open the jumper after 3 seconds, it keeps running
  • If I jumper it again while it is running after it's been removed, the power stops.

So that's some behavior I have not seen before.

Reply 7 of 8, by jheronimus

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On my board I did notice that I have to keep the power button pressed for a few seconds in order to start the system, but it's not like I need a latching switch either. Used it with at least three different power supplies, same behavior.

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Reply 8 of 8, by douglar

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The other thing that’s different about the board is that when it’s running in windows, if you touch the power switch, it cuts the power immediately. there’s no hold for 10 seconds before the power goes off. there’s no “shutting down windows” process. You touch the power switch while the computer is running and the screen goes immediately to black.