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Main => Main Forum => Topic started by: shardian on January 19, 2009, 04:15:58 pm

Title: Test bench PC power supply issues.
Post by: shardian on January 19, 2009, 04:15:58 pm

This weekend, I started to go thru my box of Gottlieb system 1 cpu boards. I fixed one up for the bench, applied the power leads, and powered on the power supply -- then nothing. I figured the board was dead, so I checked voltages, also nothing. I pulled the leads of the power supply and checked them directly - nothing again! What would cause an AT power supply to power on, yet not supply +5, and -12???

Title: Re: Test bench PC power supply issues.
Post by: shardian on January 21, 2009, 02:02:25 pm

No responses???

Title: Re: Test bench PC power supply issues.
Post by: CheffoJeffo on January 21, 2009, 02:13:20 pm

Assuming that the fuse isn't blown:

Shorted output diode ?
Bad PWM Controller IC ?
Bad "Kick Start" Circuit ?

(I just copied those from Randy Fromm's article on the subject ... I haven't actually read it yet).

Title: Re: Test bench PC power supply issues.
Post by: shardian on January 21, 2009, 02:18:20 pm

I would assume the fuse isn't blown since the unit powers on (fan runs).

I guess I'll just have to yank a new one.