No Power, No Display, No Output

[rabidgerry]

Hey MJMP, having observed my MP1 with the lid off, I can see that when I turn my unit on it definitely get's power to the tubes.  However no display or anything.  If I turn the swith on and off 2-3 times, then it comes on.  How do you think I find out what is causing the issue?

[MarshallJMP]

Does it start the first time if you get the tubes out?

[rabidgerry]

OK tested with no tubes.

It didn't come on right away WITHOUT tubes.  Then I tested it a few times more.

It started to come on without tubes.

Then I put the tubes back in, it would NOT come back on with tubes first time round.

Then I took tubes out, it did come on first time.

Put tubes back in,  powered on, then suddenly it DID turn on first time round.

Mega confusing!!!

So it seems random, it will come on first time round sometimes without tubes and sometimes not.

[MarshallJMP]

Is this unit stock or have you changed anything , like the noise mod?

Also can you take a pic of the upper right side (near the transformer/big caps) so I can see the values of the reset components?

[rabidgerry]

Nope this unit is stock, stock, stock.

Not even the rear input mod

I'll take some pics for you  :thumb-up: of the area you mentined

My noise-modded/MDRT MP1 is rocking out fine  :)

[rabidgerry]

some pics


ok had to remove links as photobucket apparently are being a bunch of fuckers and looks like my ten year relationship with them has come to an end.  I aint paying for shit to post my pics on the internet.

See attached photos

[MarshallJMP]

Can't see the pics? just something about updating your account?

[rabidgerry]

updated my last post

[MarshallJMP]

Okay I see it has one of those crappy UK transformers, this could be the problem also.

[rabidgerry]

Well thats the difference between the UK one and the US one?  Apart from the voltage of course?

Doesn't that transformer look stock to you?   (stock as in a UK voltage transformer put in by ADA)

So what can I do to test it?

[MarshallJMP]

Well the UK distributor bought ADA MP-1's without transformers in it and when they arrived in the UK they put in there own ones. But these are a lot smaller as the original ones. Later on they used bigger ones but I saw you have the small version. I replaced a few of these because they either failed on the high voltage winding or 9V winding.In the 1st pic the one on the left is an original transformer, in the middle an UK big one and on the left a small one like yours.

[MarshallJMP]

So what you can do first is to replace 2 diodes (red arrow), the 3300µF/16V cap (red arrow) and the reset circuit (red block). If that still doesn't help you could put in a larger cap so the reset circuit keep the CPU a bit longer in reset mode.(yellow arrow).

[rabidgerry]

Trust you to know all about it man!!!  Impressive as usual.

Ok I'll try get some of those components and swap them out.

On another note, is there a better transformer to get (besides the MDRT?)

I like the sound of this MP1 (its the one you said sounded "plexi-ish") so I'd be so I'm keen to keep it as close to possible.  I guess if I can get the crappy transformer to work better then I'd stick with it.  I mean really it's not a big problem right now (couple of flicks on and off with the switch) but if it has potential to worsen then might be better to replace it?

[MarshallJMP]

Well try out those things I said, if it helps ,fine if not I have a few 220V original transformers if needed. But try it out , could be a failed component but it could also be that the transformer is on it's way out. What ever it is I have your back  ;D

[rabidgerry]

Sounds good to me!

I'll track down the components I need and swap them out.

It's good to know you have my back  :thumb-up:  It's always appreciated.  That MP1 was a big part of the sound on our album so it's definitely a great one to keep living healthy!