PSU outputting wrong voltage

burgerkingdiamond · Post by **burgerkingdiamond** » Fri Nov 30, 2012 7:10 pm

I pulled out a spare arcade PSU to test the voltages and I noticed that the -5V line is outputting -16V. The +5v and +12V are fine. There is only an adjustment pot for the +5v.

Any ideas what's going on?

antron · Post by **antron** » Fri Nov 30, 2012 11:15 pm

is there a load on the supply while you measure?

burgerkingdiamond · Post by **burgerkingdiamond** » Fri Nov 30, 2012 11:47 pm

antron wrote:is there a load on the supply while you measure?

actually no.

antron · Post by **antron** » Sat Dec 01, 2012 1:12 am

then I wouldn't have been surprised if all voltages had read wacky.

burgerkingdiamond · Post by **burgerkingdiamond** » Sat Dec 01, 2012 2:08 am

antron wrote:then I wouldn't have been surprised if all voltages had read wacky.

Ok, it just seemed strange that the +5 and 12+ would be fine and the -5 would be so far out of wack. I don't have the means to test the PSU out with a PCB at the moment. So I guess I'll have to wait to figure it out.

channelmaniac · Post by **channelmaniac** » Wed Dec 12, 2012 2:40 pm

Pop the cover on the power supply and look to see if it has a 3 terminal voltage regulator for the -5v. It will be labeled as a "7905" in most cases.

If you have one in there, replace it.

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PSU outputting wrong voltage

PSU outputting wrong voltage

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