Need power supply help

[KD0GOJ]

I have a pyramid gold series 25 amp
It has output voltage 5-15 on a meter.
The protection light and buzzer is sounding.
I have searched the net and found nothing.
Help Please
I could really use this beast for a linear i got the other day
Thanks
KD0GOJ

 

[TonyV225]

Look at the bridge rectifier square piecr with wires running to it bolted to the bottom or inside floor of the chassis

 

[KD0GOJ]

Tony thanks for the reply
what setting on a multi meter?
pos to the pos and neg to the other three ?
at 1k the meter swings all the way over to the right
I did notice the cooling fan is not on,
Hooking another fan up the fan runs
But the beeping still goes on

Thanks
KD0GOJ

 

[KD0GOJ]

Ok I talked to a old friend on the phone. and was told that.
With my multi meter on ohm, With the pos lead on pos and the neg on all othr post full swing should be seen and if you put neg on pos and pos lead to others you should see no movement.
The bridge rectifier show full swing both ways
Looking for a KBPC3501 SEP

KD0GOJ

 

[Robb]

WIth the power "off" - of course...on that last post...

Is this a switching-type supply - or does it have a transformer? I couldn't find any info on your supply. If it has a transformer, then you might have to check the pass transistors as well; they can also go bad. Shorted filter caps too - be careful to discharge them before checking.

 

[Beetle]

On some multimeters, like the Simpson 260 series, the RED lead is actually NEGATIVE when on a resistance scale. As the owner of a multimeter it's up to you to verify whether this is true for your meter and either trust your memory or make some sort of a reminder on the meter itself. I have several Simpsons, AN/PSM-4s and other instruments with Dymo labels on the glass reading "RED LEAD NEG ON OHMS".

As for checking the bridge, you have two terminals with AC applied and two with the DC produced by the bridge. I generally open one corner of the bridge if it's possible; doesn't matter which one. Then I measure forward and backward across each of the diodes, using the Rx10 or Rx100 range and looking for any diode that doesn't show a good F/B ratio.

Then, don't forget to reconnect the corner you opened!

 

[TonyV225]

If your trouble was the bridge rectifier then if you replace it Ide use a KBPC5010 thats what I do with them anyways. The inrush current is pretty hard on these 3501. You also have a PM.

 

[KD0GOJ]

Ok folks thanks for the help.
The power supply does have a transformer.
Will look into how to check the pass transistors.
Just had a thought that the other pyramid power supply might have the same
bridge rectifier.
Might see about a quick switch to see if that is the problem
Not sure if i will get to it today
65 outside If 10 doesn't open than out i go to start working some dirt for veggies
Thanks KD0GOJ