The short question would be, is it possible to modify ATX 2.2 PSU(or/and motherboard) so that computer will boot up and work properly without +5V STB?
The background of my question is fallowing:
I found out that my motherboard(MSI MS-7027) has some unnormal voltages when the computer is turned off(but the PSU is ON)- it has ~3.5V instead of 0V in +12V line. Probably some component is leaking +5V STB through to the +12. I wouldn't bother, but I have replaced my graphics card(both were nVidia GF FX 5200) twice in two weeks. I think that this ~3.5V, instead of 0V as it should be when the computer is turned off, have something to do with it.
**broken link removed**
MSI MS-7027
At first I thought that this is caused by some capacitor, but tests with resistors proved that the voltage(~3.5V) is stable and constant. So I thought that there are any other possibility than leakage of +5V Standby. So I cut the +5V Standby wire to prove that I am right/wrong. Check that on the second image:
**broken link removed**
As you can see, the 3.3V, 5V, 12V, AGP pin#1 and SYSTEM FAN pin#2 are now correct! However, the voltages of the Power ON has dropped from ~5V to 1.7V!?
To prove, that this is not a PSU fault, I tested with two other PSU's. Results are here:
**broken link removed**
However, computer will not start when the +5V STB is broken. So I made a simple switch to power on the computer when the +5VSB is broken, but there was no video output. Computer completed POST(no beep codes and three lights on the keyboard lit up for a moment), but then there was no video output! When I changed the PSU to the one which has working +5V STB, the video output was back. I have few image as well:
**broken link removed**
**broken link removed**
The motherboard is a rather rare OEM microATX motherboard for a multimedia computer in a very nice special custom made case- I would really like to fix this rather than replace.
However, why was there no video output when I used regular on/off switch? Is it possible to modify ATX 2.2 PSU(or/and motherboard) so that computer will boot up and work properly without +5V STB?
The background of my question is fallowing:
I found out that my motherboard(MSI MS-7027) has some unnormal voltages when the computer is turned off(but the PSU is ON)- it has ~3.5V instead of 0V in +12V line. Probably some component is leaking +5V STB through to the +12. I wouldn't bother, but I have replaced my graphics card(both were nVidia GF FX 5200) twice in two weeks. I think that this ~3.5V, instead of 0V as it should be when the computer is turned off, have something to do with it.
**broken link removed**
MSI MS-7027
At first I thought that this is caused by some capacitor, but tests with resistors proved that the voltage(~3.5V) is stable and constant. So I thought that there are any other possibility than leakage of +5V Standby. So I cut the +5V Standby wire to prove that I am right/wrong. Check that on the second image:
**broken link removed**
As you can see, the 3.3V, 5V, 12V, AGP pin#1 and SYSTEM FAN pin#2 are now correct! However, the voltages of the Power ON has dropped from ~5V to 1.7V!?
To prove, that this is not a PSU fault, I tested with two other PSU's. Results are here:
**broken link removed**
However, computer will not start when the +5V STB is broken. So I made a simple switch to power on the computer when the +5VSB is broken, but there was no video output. Computer completed POST(no beep codes and three lights on the keyboard lit up for a moment), but then there was no video output! When I changed the PSU to the one which has working +5V STB, the video output was back. I have few image as well:
**broken link removed**
**broken link removed**
The motherboard is a rather rare OEM microATX motherboard for a multimedia computer in a very nice special custom made case- I would really like to fix this rather than replace.
However, why was there no video output when I used regular on/off switch? Is it possible to modify ATX 2.2 PSU(or/and motherboard) so that computer will boot up and work properly without +5V STB?