Denon PMA 250 transformer

[stevekendal]

I had a PMA 250 given with a dead mains transformer (Already removed). Can anyone tell me please what voltage the secondary puts out, as I may have a suitable replacement in my junk box. Steve.

[stevekendal]

Originally Posted by stevekendal

I had a PMA 250 given with a dead mains transformer (Already removed). Can anyone tell me please what voltage the secondary puts out, as I may have a suitable replacement in my junk box. Steve.

The smoothig caps are 50v, so maybe its 30-0-30?

[Mooly]

Sounds reasonable... a 30 volt rated winding will be a little higher at light loads too, so it sounds spot on to me.
If it's say 33 volts then that's 46.6 volts DC per winding. Perfect

[Hairy McClary]

I have just tested one from a PMA-250II which I had to rewind thanks to a blown thermal fuse. (Don't ever try to rewind one of these, they are a damned 'mare to put back together and to get the windings tight enough.)

Once I had rewound it and I am pretty certain I used the same number of turns, I found the secondary voltage to be an odd amount: 50V~ exactly, with at the time mains voltage of: 246V~

I would have thought this should have been lower, but it says what it says. There must be some voltage drop along the way, as the caps are 50V.

I think my transformer voltage reading may be wrong though, but this was only through the extremely light load of the multimeter, so when it is under load and rectified this would be very close to the maximum voltage of the caps, if not over, if anyone has the true rating, I would like to know also.

Just thought I'd post this to let you know of my findings.

[Hairy McClary]

oh dear god, I I too tired right now, the transformers is around 25-0-25, mine read between 25.0 and 25.6 on each side, I really wasted my writing time on the last post, sorry if you read it all lol.