No input front or rear MP-1

[Mxzx]

Couple more.

[MarshallJMP]

Rear jack looks good,can you take a pic of the connections on the front jack?

[Mxzx]

Here ya go!


Thanks!!

[MarshallJMP]

Problem is i can't see which blue wire goes to the rear and which one to the front?

Saw you removed the bridgewire,does it work now?

[Mxzx]

Both blue wires are soldered on the tip terminal.

Still no input after removing jumper.  I did notice that tube closest to front is much more microphonic when tapping on it compared to other one.

[MarshallJMP]

Are both blue wires soldered to the same terminal?

[Mxzx]

Yes

[MarshallJMP]

Ok that won't work,so the blue wire comming from the rear jack has to be soldered on the middle lug,the blue (short) wire comming from the pcb has to be soldered to left lug,white wires are fine like they are now.

[Mxzx]

I'll swap it out and see what happens, thanks again!!

[Mxzx]

Okay, swapped the wires and still no input on either jack.

When the level is cranked up, you can hear a faint signal through the amp, tons of hiss but it is in there.  Doesn't sound like it is being processed, i have it on preset 1 and the faint signal sounds clean, no distortion.

I do have an oscilloscope and signal generator now if we need to go that route.

Thanks for all your time on this!

[MarshallJMP]

Ok well hooup the signal generator and start with the scoope at the input and follow the schematic.Let me know if i can help.

[Mxzx]

Ok, got the scope and signal generator hooked up.  All tested out.

Where do I start probing?  I'm a novice here so baby steps!

Thanks,
Michael

[MarshallJMP]

Good starting point is U4 pin1.See if you have a signal there.

[Mxzx]

Thanks, I'll let you know Friday afternoon.

I'm not at home, but is this easy to find on board? 

Also should I have the MP-1 powered up while checking?

Thanks!

[MarshallJMP]

It's easy to find,if not send me an email.

Yes powered on,else it won't work  be carefull with the high voltage.