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Have you set it up properly ? Consult instruction book. If you are certain it is defective, get a refund under the warranty (if it's new it should still be under guarantee)
18.January.2015.
Hello Brenden, Did you find the value for r13 on the Mobitronics MPS-50A power supply? I am looking for that value also. I cannot locate where R13 is on the board so if you give me some direction I may be able to help. I do not have a diagram just a power supply that I am trying to repair also. Cheers Stewart Sydney Australia
Sounds like the regulator goin. I've read when they go bad it will go full voltage which is 37vdc. Looks like they use the LM723 regulator. I'm no expert, but may be that simple. Here's a link to a schematic. Hope it helps http://www.pyramidcaraudio.com/manuals/PS52K.pdf
I have a PS14KX. It won't handle any load. If you have any ideas let me know
I have used this tech for repairing some of my radio equipment and found him to be honest and dependable A rare thing now days. check with him at [email protected]. Unless you are wanting to take a shot at repairing it yourself if so I will do some searching myself to see if I can give you a hand on it.
I'm not sure what you mean by 'wide open voltage'. If it's over 17v, the supply may have multiple problems. I don't have the 52kx schematic but other Pyramid supplies have over-voltage protection. There is an SCR that is triggered when the voltage gets to ~17v. This should clamp the output and trigger a shutdown. You should check the 16v Zener diode and the SCR. If the SCR or the Zener is defective, that would prevent the over-voltage from clamping the voltage. Also confirm that the SCR has a solid connection to the ground terminal of the supply. If it's open, that could prevent the clamp from shutting down the supply.
If the voltage is going high, measure the DC voltage from pin 4 to pin 5 of the LM723. It should remain the same at all times. Also measure the voltage from pin 5 to the ground terminal of the supply. That should also remain constant at all times.
The problem I have had with a PS-20 is a blown capacitor. Hooked to a radio, would allow radio to receive fine, but when trying to transmit, amperage would bottom out. Behind the transformer is a large circuit board. UNPLUG POWER SUPPLY, remove cover, Undo the two nuts, flip board over, and gently rock the 4700uf capacitors side to side. If they move more than 1/16th of an inch, chances are they are blown. Remove/replace and should be good to go...
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