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Power supply lost -5 volts

chuppyh

Oct 8, 2013
3
Joined
Oct 8, 2013
Messages
3
I've checked with my checker I've lost -5 what would cause it how do I fix?
Would it be a diode are a resistor
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
It's a diode. The third one from the left. LOL

What kind of power supply is it?
Can you post some photos of the main circuit board?
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
Follow the -5V wire back to the board and trace the track. It may go to a 7905 regulator as Claas suggested, or it may be supplied from a winding on the main transformer via a diode. Check for broken tracks, dry joints, and broken joints, and VERY CAREFULLY check the pin voltages on the 7905 if there is one.

Have a look at some general schematics for PC power supplies. You will be able to see how the -5V rail is generated.
 
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