Skip this paragraph to jump straight to the problem. Trying to get an old computer running again in my restaurant. We just use it to stream Pandora in the dining room (I take the audio out and feed to and amplifier) and chefs use it to look up recipes and do a few things with Word and Excel. It has an old Windows OS on it, I believe it's Windows 7. Restaurant is closed so I'm trying to be frugal and have time to troubleshoot and get things ready for when we can open again here in Santa Monica CA.
PSU is Thermaltake TR2 430W, HD is WD2500AAJS, Motherboard says Asrockk H61M-DGS and one Kingston RAM 8 GB installed. No other peripherals. Monitor, keyboard and mouse disconnected. One day the computer failed to work. Abrupt failure.
Front panel power light comes on but does not boot up and PSU and CPU fan do not come on. When I disconnect the 12V 4 pin connector to the MB and power up the computer the PSU and CPU fans come on and stay on. Back probed all the colored pins on the 24 pin connector: 5V on reds, 3.2V on oranges, 12V on yellows, -11.3V on blue, 5V on purple and 5V on gray. I believe these are within spec. If the CPU 4 pin is connected then I loose all voltages (OV back probe). Can a bad MB or CPU cause the PSU to loose all its power? Or is the PSU failing because it has gotten so weak that it cant power the MB with 12V? PSU has no trouble powering the 12V CPU fan and the PSU fan when MB is disconnected from 4-pin 12V connector. If I had spare PSU I'd try it out but I don't want to spend $ throwing parts at this computer before having some expert recommendation. I prefer troubleshooting rather than throwing parts at the problem if possible.
Other things:
All the MB capacitors look fine, no swelling or leaking.
Don't see or smell any obvious bad components or traces on either side of the MB.
Cleaned MB of all dust and cleaned again with electronic contact cleaner.
Disconnected front panel USB connectors. (the rear USBs are integrated into the MB so cant disconnect them).
Removed RAM as a test (made no difference).
Removed CMOS battery (measures 3V) and held down power button for 1 minute with power cord disconnected.
Please help.
PSU is Thermaltake TR2 430W, HD is WD2500AAJS, Motherboard says Asrockk H61M-DGS and one Kingston RAM 8 GB installed. No other peripherals. Monitor, keyboard and mouse disconnected. One day the computer failed to work. Abrupt failure.
Front panel power light comes on but does not boot up and PSU and CPU fan do not come on. When I disconnect the 12V 4 pin connector to the MB and power up the computer the PSU and CPU fans come on and stay on. Back probed all the colored pins on the 24 pin connector: 5V on reds, 3.2V on oranges, 12V on yellows, -11.3V on blue, 5V on purple and 5V on gray. I believe these are within spec. If the CPU 4 pin is connected then I loose all voltages (OV back probe). Can a bad MB or CPU cause the PSU to loose all its power? Or is the PSU failing because it has gotten so weak that it cant power the MB with 12V? PSU has no trouble powering the 12V CPU fan and the PSU fan when MB is disconnected from 4-pin 12V connector. If I had spare PSU I'd try it out but I don't want to spend $ throwing parts at this computer before having some expert recommendation. I prefer troubleshooting rather than throwing parts at the problem if possible.
Other things:
All the MB capacitors look fine, no swelling or leaking.
Don't see or smell any obvious bad components or traces on either side of the MB.
Cleaned MB of all dust and cleaned again with electronic contact cleaner.
Disconnected front panel USB connectors. (the rear USBs are integrated into the MB so cant disconnect them).
Removed RAM as a test (made no difference).
Removed CMOS battery (measures 3V) and held down power button for 1 minute with power cord disconnected.
Please help.
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