MP-1 got Noisy...

[rabidgerry]

time to fix this issue!

I tested front and back inputs they sound the same still have the noise.  Still have to check the tubers.

I cannot recall where I left off in the noise mod  MJMP I shall need your help on what it is left I have to do.  I'll send you a photo of the caps I have left over.

[MarshallJMP]

Well also send me a pic of the mp-1 pcb this way I can see both.

[rabidgerry]

[MarshallJMP]

Ok, seems you need to replace C8,C2 and C1 on the tube board, also C16,12,13,7 and 6 on the tubeboard.

Then on the mainboard all the small caps near the voltage regulators (near the MDRT).

[rabidgerry]

Just out of curiosity, those caps which I know I need to replace, they wouldn't cause the noise I'm getting right?

The noise is now so loud no guitar can be heard.

[MarshallJMP]

Well if one of those big caps on the tubeboard is busted you could get hum.

[rabidgerry]

When you say big caps?  I replaced the big ones near the tranny so they should be good.  Or do you mean one of the smaller ones that I have yet to swap out?

The noise is actually insanse now I must record it and let you all hear it.

[MarshallJMP]

I mean the caps on the tubeboard, not the mainboard.

[rabidgerry]

ok as the guide stops pretty suddenly it seem I have about 10caps I have no clue what to do with.  I started taking them out thinking I could just match them up with the right values...............WRONG!

you're going to have to help me out MJMP.  Will email ya.

[MarshallJMP]

Okay, I remember now, I gave you some extra caps not mentioned in the manual.

[rabidgerry]

emailed you mjmp the caps you give me and hopefully you can tell me where they go.  Soon as I get those installed, we shall see if the noise is still there.  If the noise is still there, further investigation will be needed :thumb-up:

[MarshallJMP]

I send you the new updated manual but except for some caps the rest was also explained in the old manual.

[rabidgerry]

I was hoping to update the manual also.

I'll do up a draft FINALLY, now I have some time to do other things than make an album   I have my life back again  :lol:

[rabidgerry]

So replaced the caps on the tube board and tested.

Strangely the insane noise I was getting the last time I tested, which was louder than the actual guitar signal"!!!!  is gone....................

seems a bit strange to me as this noise was crazy loud.  I wonder did opening and taking the guts out move something back to where it should have been?  The caps alone don't seem entirely responsible for the fix.

Who knows perhaps they are.  MP1 sounding f**king awesome!  Gonna rehearse with it today.

Will replace the last few caps tomorrow ones situated at the MDRT.

[MarshallJMP]

Well it could be, if one (or more) high voltage caps were bad then you get hum.