Different PSUs and Different Motherboard Test Results

[KenOlson]

Received an old nonworking PC because the owner did not turn off the PC when tried to connect a new HDD and blew the PSU.

Separately tested the Memory, HDD, Floppy and CD drives on a "Good PC" so decided to use the PSU from the "Good PC" and while did not get any "error beeps" the screen was black so thought the Motherboard Video section had been damaged.

Since I am new to testing Motherboards, did not want to inadvertantly destroy any "Good PSUs" so decided to post "Recommend a PSU for Benchtesting Motherboards" https://www.badcaps.net/forum/showthread.php?t=5688

PCBONEZ recommended using a Server PSU so tried a working AOpen FSP300-60BT. When connected it to the above Motherboard using the same minimal Memory, Floppy and CD drive hardware the on board Video worked!

Would like to learn from this experience so appreciate any comments why the onboard Video did not work with the first "Good PSU" but did with the "Server PSU"?

Also if anyone would like me to post photos of either the original or first "Good PSU" Please let me know.

[KenOlson]

Re: Different PSUs and Different Motherboard Test Results

Forgot to mention the original blown PSU was an Ilssan 120W and the first Good PSU was an AcBel 100W. The AcBel was not damaged and when reconnected to it PC everything worked.

Discussion of the AOpen Server PSU is "AOpen FSP300-60BT PSU for Benchtesting Motherboards?" https://www.badcaps.net/forum/showthread.php?t=15093

Am wondering if anyone else has han an experience like this?

Ken

[PCBONEZ]

Re: Different PSUs and Different Motherboard Test Results

I think the 100W simply wasn't high enough capacity.
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You also need to pay attention to the -5v rail.
It is now obsolete and gone on newer equipment [including PSUs] but some old equipment still needs it to work.
-5v was for the ISA BUS.
Lack of an ISA -slot- doesn't always mean there is no ISA BUS on a motherboard because sometimes they include the BUS and mount chips [sound, LAN, etc..] directly on it as on-board devices.
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