RM4 switching problem again

[ilearn]

My RM4 had a channel switching problem.
Channel 1 was always on. I had to take the module out from channel 1, then everything was fine.
I put a new MIDI board and the problem went away.

About a month and a half later, the problem came back.
This time channel 2 LED keeps coming back and the volume drops half.
I did usual cleaning and checkups. Tried different modules, cleaned the contact surface, even changed the tubes.

Then today I found out that if I don't put any module in channel 1, the problem goes away. So I guess I'm back to square 1.

I searched the forum and there were reports with similar symptoms, but there were no solution reported. Maybe my search wasn't thorough enough..

If any MTS users had similar problem and solved it, please let me know.
I love my RM4. 3 channels are simply not enough.

 

[Jaded Faith]

Jaemin,
I just returned to work and replied to your email about this. You need a qualified/experienced technician to troubleshoot and isolate the point of failure at this point. This is not a DIY repair at this point.
Let me know if you did not receive my email with greater details and I can resend it.
Rob

 

[Nightdare]

ilearn

Do you unplug/plug in the footswitch with the RM4 ON?

 

[ilearn]

No, I didn't. no need to.
I'm using G-system to select the channels.

 

[ilearn]

My local tech took my RM4 apart and he couldn't tell me what exactly was wrong and he said he will try new optocouplers. Since it might take more than a week or two, I brought RM4 back home.

I plugged RM4 with my rig and...

The problem was all gone.
Everything was normal again.

My tech took apart all the PCBs and cleaned all the contacts, including transformer.
I only cleaned the module contacts and tube sockets, before I took my RM4 to the tech.

I guess my RM4 needed a thorough clean up.
Anyhow, I'm a happy RM4 user again.

Cheers!

 

[flamed1]

Glad you got it sorted out!

 

[lebobl]

Resurrecting this thread! I am having the same issue with channel one switching in and out. Any recommendations for how to clean it appropriately? I know how to open it and I do have Deoxit. Like the OP, the RM4 works perfectly if module 1 is out. Thanks!

 

[lebobl]

What's so crazy is that if I run a dual-channel module in slot 1, everything works perfectly. But if I switch to a single channel module there, it's all screwy with the flickering switchiing.