Peavey VMP-2 PSU

[tofufo7]

Hey all,
My Peavey VMP-2 psu left me last night... main power transformer is dead (primary opened), the PSU card is partly burnt and can not identify all burnt components...
Unfortunately this card is an other revision than the A one we can find on the web, slightly different.
So, my questions are:
Is anybody have an other than revision A schematics? and anyone can confirm me that we should have as secondary out: 24VAC, 153VAC, 163VAC from the transformer?
Best
Christophe

 

[JohnRoberts]

I suspect the power transformer primary open is caused by an internal thermal fuse that opened up. This would generally require a replacement transformer.

Looking at the PS picture, the smutz around the rectifier diodes cause me to ask if perhaps you have a shorted diode. A shorted diode could draw a lot of current possibly trashing the transformer. Check the diodes with a VOM, if they didn't evaporate they will still indicate a short circuit. If the diodes all measure with good junctions, ignore me....

JR

 

[tofufo7]

Thank you so much John for your message!
Yes, you are absolutely right, I can see that one of the diodes is shorted (the one below the carbon burnt underneath the horizontal big 47uF cap).
So, I will clean and repopulate this area and swap all caps with new ones and order a new power transformer.
I have a guy in Greece who can built a special one for me, but I have to give him and be sure of all voltages and currents...
Best
Chris