POWER SUPPLY VOLTAGE TOO HIGH

[darticus]

This is a pyramid supply with only 3 amps but it shows a voltage of 21.9 volts. Usually they will show 13.8 volts. Any suggestions would be great. Anything I can check would help. Maybe its fine??? Thanks Ron

 

[AK9R]

I gather it shows 21.9 volts with no load. Nonetheless, that's pretty awful regulation. I think I'd send it back.

 

[darticus]

SORRY I should have discribed it better. This is an old pyramid PS8K power supply. I hate to toss it out if there is an easy fix. I can't find a schematic for it. Thanks Ron

 

[wtp]

load it

have you tried it with a simple load?
try a 12v light bulb, one that you could sacrifice so to speak.

 

[k3cfc]

SORRY I should have discribed it better. This is an old pyramid PS8K power supply. I hate to toss it out if there is an easy fix. I can't find a schematic for it. Thanks Ron

Ron i sent you an email.

 

[darticus]

Thanks buddy! later Ron

Ron i sent you an email.

 

[darticus]

Wouldn't you just blow the bulb or do you think the voltage will tank with a bulb added? Thanks Ron

have you tried it with a simple load?
try a 12v light bulb, one that you could sacrifice so to speak.

 

[ve3wej]

I would suspect the pass transistor on the back, may be shorted... usually a 2n3055 in the old ones.
did you find the schematic???

does it have the lm323??? i think the number is in the unit, check it as well

 

[z96cobra]

The idea behind the 12v bulb is to see if the radio settles to an acceptable voltage once the load (the bulb) is applied. If the voltage continues to run 21.9v, you blow a $.50 bulb vs a $500 radio, not that I'd hook any radio to a power supply that can't maintain itself @ a proper voltage, with no load!

 

[majoco]

I'm with VE3WEJ on this one.

If you don't fix it and just carry on putting light bulbs across the output, the next thing to go bang will be the bridge rectifier or the transformer - then it's a paperweight.

Whatever you do don't connect a radio to it.