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90's psu to "test" atx-12 mobo?

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October 4, 2010 11:19:52 AM

~2002 early atx12 ECS L7VMM2. I've assumed it was killed (years ago) by notorious Bestec ATX-250-12E. (emachines amd 2100+)
the ram and hdd survived, but i don't know if that indicates likelihood mobo survived.
I'm about to ewaste it with some late 1990's k6 that nobody wants.
But i wonder if late 1990's plain atx psu can "test" whether the ECS mobo survived the bestec's suicide.
These 90's psus are small, but the mobo powers only the cpu and whatever onboard stuff. Just some POST beeps shouldn't need a lot of of psu power? (save even more power by unplugging the cpufan in very first "test")

I guess first I should inspect the mobo for flaky capacitors.

I don't have much test equip. A neon electricians "tester". An 80's volt,ohm,ammeter i won't sacrifice death by a possibly vengeful mobo.

so the question is whether the old psus have any value in "testing" the motherboard.


If the old psu gives good result, I might want to try a Newton NPS-250HB A (atx12 20+4 (IIRC) PSU from ~2002 era).

thanks..

More about : psu test atx mobo

a c 272 ) Power supply
October 4, 2010 1:17:34 PM

You can use a modern PSU, the old systems that ran off of 3.3V and 5V didnt use much power so even a modern 12V based PSU with weaker 5V and 3.3V rails should still have plenty to handle it.
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October 4, 2010 5:04:44 PM

hunter315 said:
You can use a modern PSU, the old systems that ran off of 3.3V and 5V didnt use much power so even a modern 12V based PSU with weaker 5V and 3.3V rails should still have plenty to handle it.


Hi, that's useful.
but I want to "test" newer 20+4 pin mobo, with older 5v/3.3v 20pin psu. whether a healthy 2002 mobo (bare) would START on a ~1998 5/3.3v psu is what matters.
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a c 144 ) Power supply
October 4, 2010 7:06:31 PM

History lesson:
Long ago, they had 20 pin PSU connectors and everything was powered from the motherboard. Components became more power hungry.

PSU connectors went to 24 pins. The four extra pins were one each 3.3, 5, and 12 volts and a ground. CPU's got their own 12 volt connector and power through the main power plug dropped.

Video cards got bigger and got their own 12 volt power connectors and 5 volt power through the main power plug dropped.

RAM went from SDRAM (3.3 volts) to DDR2 and DDR3 (1.65 - 2.2 volts) and 3.3 volt power through the main power plug dropped.

You shouldn't have any problem running a modern 24 pin motherboard from a 20 pin PSU provided that it has adequate 12 volt capacity for the CPU power and any needed GPU power. And provided that the PSU is not generic junk.
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October 16, 2010 8:39:53 PM

Question comes to:
Which psu rail feeds the cpu?

A lot of research, distills to:
The mobo (chipset) determines which psu rails supply what.
http://www.ecsusa.com/ECSWebSite/Product/Product_Detail... doesn't give that type info
Best info is by inference from
1) dead bestec psu (though the label may be PR puffery). the psu has 20pin and only p4 4pin, so is early atx12 1.0. Mobo implying.
2) mobo lacks any aux, has only 20pin, suggesting 12v limited by old atx spec. so cpu obtains mostly from 5v.

I "tested" with a 1998 cwt-250atx, that has slightly lower ratings except same overall 250w and same +5v.
Results:
First power on, cpufan spins but no beeps.
So inserted one dimm. same outcome. only cpufan and ram red led1 lights. Also, can hold power button on case to force power off. Seems no other functions.
After clearing cmos jumper, then reconnect, power on, same outcome.
Conclusion: board is essentially dead.

This thread is essentially "solved", but I don't know if i'll be able to mark it solved because this posting ware is so broken. I haven't been able to log in or post except from only one pc (same os, browser, profile, similar setup, etc)
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