BOSS ME-50 input stopped working

[Slobrain]

My Nephew has a Boss ME 50 pedal board and the guitar input stopped working. I checked the input jack and its working, no broken solder joints. I can plug a MP3 player into the aux input and that works as I can hear the music coming out to the amp, all the switching of effects work but no sound when the guitar is plugged into the unit.

Anyone now if this is a known issue with these pedals? any help would be appreciated.

Thanks

Slo

[dwmorrin]

The manual suggests checking that it's not in tuner mode, or that the expression pedal is not muting the output.
I would also do the factory reset before getting too crazy with the guts. (Hold down bank"<-" and "write" while turning ON, then press write, press write again)
After that, it's time to inject a signal and trace away, or call Roland.

[Jazz P Bass]

The signal from the jack goes through a small value capacitor, a 10K resistor & then it hits a JFet.

Check that you have signal at the gate & drain.

If you do, then move on to IC2, pin 1.

If it is there, then it hits a Codec ic.

http://www.akm.com/akm/en/file/datasheet/AK4552VT.pdf

The Aux In takes a totally separate & different path.

[Slobrain]

The manual suggests checking that it's not in tuner mode, or that the expression pedal is not muting the output.
I would also do the factory reset before getting too crazy with the guts. (Hold down bank"<-" and "write" while turning ON, then press write, press write again)
After that, it's time to inject a signal and trace away, or call Roland.

LOL...My nephew said he did the factory reset when it stopped working so when he brought it to me today I plugged it in it wasn't working. Took it apart to make sure the input jack solder joints were not broken loose. I put it back together then did the factory reset myself and its working now... I should have did the reset before opening the darn thing up... My nephew originally thought he broke the input jack as it was loose. I guess I need to teach him about keeping stuff tight so it doesn't break...

Thanks for the info guys. The reset did the job. Thanks Jazz P for the schematic too.