Wanted Vestax PMC-250/250-r service manual

[maxdegam]

Hello,

first post to this forum, I've seen other service manuals available here for old vestax so i'm trying my luck!

Anyone would have the service manual for the PMC-250 or PMC-250r? One of the diode on the power pcb have blown out and i need to find a replacement for it. I don't know the value..

I think it's written 43T on the diode if it can help..! Anyone?!

Thanks!

 

[MAAC0]

VESTAS PMC-250 Service Manual download, schematics, eeprom, repair info for electronics experts


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[PRR]

Rectifiers rarely die alone. Usually some downstream part shorts-out, killing the rectifier.

I would just use 1N4007. But specifically they used a "fast recovery", which may reduce switching noise. Or may just have been the part they used everywhere; this power supply is very basic no-frills (because no frills really needed to power opamps).

Where it says "DC In" should be "AC In".

 

[maxdegam]

the problem i have on the mixer is no matter what i do there's a big buzz coming out of the main out.. even if i turn everything down it is still making a loud noise around 0dB..

Does it ring a bell to anyone?

Thanks

 

[MAAC0]

IS it buzz or hum ?


Hum is PSU related. check PSU caps and rectifiers.
Buzz can be many things including RF interference. Check grounds and connectors. Wiggle cables etc.


Trace the signal from the input to the output.
At each op-amp output check the signal.
You'll probably find a faulty IC or a surrounding faulty part.

 

[PRR]

In that circuit, a failed rectifier IS a "BIG buzz".

Replace it. See what else smokes. In fact I would replace C44 C45 just on suspicion. (It is less likely to be downstream because the regulators will shut-down first.)

 

[maxdegam]

Thanks to all!

I bought replacement part for all the power supply and changed the 4 capacitors, 2 diodes and 2 rectifiers. It solved the problem!