No Power, No Display, No Output

[rnolan]

I just checked the (now spare) Australian transformer that Mike replaced with MDRT.  It looks like the one on the left with black tape.  I need to check my 240v MP1 that only worked for a little bit, as MJMP you said (back when I bought it) the problem may be power related.  The US MP1 I have works fine but (obviously) needs a step down transformer (which are heavy and a pain...)

[Chip Roberts]

Zombie thread:

After getting a new MP1 (which I love of course), I gave my old one to our other guitar player, as he's an electrical engineer and is interested in old tech like this.  He replaced one of the diodes and BOOM-it works.  Still needs some more work done, like replacing input jacks and volume pots, but now I have another MP1 for backup  :headbanger:

[rnolan]

Fantastic  :thumb-up: :whoohoo!:

[MarshallJMP]

Chip, could you ask him which diode was busted? it seems some of them start to fail

[Chip Roberts]

Not sure if this is helpful or not.  This was either the replacement or the original one before he pulled it out, but that's where it's located I guess  :dunno:

[Chip Roberts]

Here's another one of him testing it before the replacement with what looks like some sort of sonar device?

[MarshallJMP]

Did he replace the crystal? (the metal can like thing with the long legs)

Hmmm funny, never heard someone saying a sonar device to an oscilloscope  ;D

[Chip Roberts]

He did say something about having to order a diode with the correct crystal, yes.

[MarshallJMP]

Well it could be bad diode or a bad crystal or even both.