MP-1 MIDI not working

[niksa]

I have a strange problem with MP-1. It all started without any external cause. MIDI on MP-1 isn't working at all. I've tried with two MIDI controllers (one which worked till the problem appeared and another Engl one). Both of controllers work because they are sending MIDI signal to other devices without any problems. I tried changing channels from omni to 1-16 (and accordingly on controllers) - no luck there. I've tried with factory recall - still no luck. Lastly, I've disassembled MP-1 and traced pins from cable to PCB where MIDI input connector is soldered - I have 0 ohms between pin 1 on the cable and pin 1 on PCB etc. which means that connector isn't broken.
Does anybody have any solutions for this?

Thanks in advance

[MarshallJMP]

Try too hook up a midi pedal to the mp-1 midi in and run a midi cable from the midi tru to an other midi divice and see if something happends on the other midi device.This way i can rule out some things.

[niksa]

Thanks for the help but this MP1 is weird. Just like it has stopped working it started to work again without any reason :S
It's working now but not sure for how long :/

[rnolan]

Maybe give ALL the connectors a clean with decent contact cleaner (MJMP whats that one you recommend ?), also take the lid off and give your pots a spray/clean. Can't hurt and is probably long over due ?
Cheers R

[MarshallJMP]

Could be a bad cable or a wornout midi in jack.

[Sparker]

Other suspects could be damaged joints on the MP-1 MIDI connectors giving intermittent fails (try re-soldering the MP-1 MIDI connectors on the PCB), or the opto-isolator on the MP-1 MIDI in side could be damaged (see MJMPs MIDI in - MIDI thru test mentioned earlier).

[HerlonGuitar]

Hey guys! I'm just another guy with an MP1 that Midi doesn't work. Some help?

As MarshallJMP1 mentioned:

"Try too hook up a midi pedal to the mp-1 midi in and run a midi cable from the midi tru to an other midi divice and see if something happends on the other midi device.This way i can rule out some things."

Yes! The other device works through the MP1's midi thru

[MarshallJMP]

Did you try to set midi channel to "ALL"?

What happends if you hook it up to the midi out?

[HerlonGuitar]

Did you try to set midi channel to "ALL"?

What happends if you hook it up to the midi out?

Yes. Tried to all the combinations as possible .

MiDi Out doesn't work too. I tried to Controll other device  from MP1 MiDi out. Nothing.

[MarshallJMP]

Could be a busted UART, they can fail sometimes. It's the big 40 pin ic on the midi board. You could try to replace it, it's in a socket so quite easy to do.

There are 3 different ones you can get, the COM8502, TR1863 or the COM8017. Or this one should work too, HD3-6402R-9.

But before you order a new one, try to reseat it, also do this with the grey flat cable going to the mainboard (on both sides)

Keep us updated.

[HerlonGuitar]

Could be a busted UART, they can fail sometimes. It's the big 40 pin ic on the midi board. You could try to replace it, it's in a socket so quite easy to do.

There are 3 different ones you can get, the COM8502, TR1863 or the COM8017. Or this one should work too, HD3-6402R-9.

But before you order a new one, try to reseat it, also do this with the grey flat cable going to the mainboard (on both sides)

Keep us updated.

Thank You so much, Man.

Would that bê?

https://produto.mercadolivre.com.br/MLB-1316954917-circuito-integrado-com8017-_JM

[MarshallJMP]

Yes if it's a COM8017 it should work