RM4 switching problem again

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ilearn
RM20
Posts: 24
Joined: Wed Feb 17, 2016 3:14 am
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RM4 switching problem again

Post by ilearn » Mon Apr 18, 2016 6:43 am

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.
RM50
RM4
Dumble HRM(ish)
Fender Blues Deluxe
TC G-system
VHT2520


http://weplaymusic.co.kr

Jaded Faith
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Post by Jaded Faith » Mon Apr 18, 2016 8:36 am

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
www.jadedfaithmods.com
https://www.facebook.com/JadedFaithMods
Email: info@jadedfaithmods.com
Authorized Service Center for US Music and Egnater
Authorized Reseller for Celestion, Scumback & Mercury Magnetics

Nightdare
Lynch Box
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Location: The Neverlands

Post by Nightdare » Fri Apr 22, 2016 8:23 pm

ilearn

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

ilearn
RM20
Posts: 24
Joined: Wed Feb 17, 2016 3:14 am
Contact:

Post by ilearn » Fri Apr 22, 2016 8:53 pm

No, I didn't. no need to.
I'm using G-system to select the channels.
RM50
RM4
Dumble HRM(ish)
Fender Blues Deluxe
TC G-system
VHT2520


http://weplaymusic.co.kr

ilearn
RM20
Posts: 24
Joined: Wed Feb 17, 2016 3:14 am
Contact:

Post by ilearn » Mon Apr 25, 2016 2:26 am

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!
RM50
RM4
Dumble HRM(ish)
Fender Blues Deluxe
TC G-system
VHT2520


http://weplaymusic.co.kr

flamed1
RM20
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Joined: Wed Apr 29, 2015 12:18 pm
Location: Sunny So. Cal.

Post by flamed1 » Fri May 06, 2016 2:22 pm

Glad you got it sorted out!

lebobl
RM50
Posts: 67
Joined: Fri Sep 27, 2019 1:57 am
Location: St. Louis, Missouri

Re: RM4 switching problem again

Post by lebobl » Sat May 02, 2020 2:40 pm

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!
Randall RM4
Fryette PS2
Mesa 2x12 Recto Cabinet w/ Celestion V30s
Modules: Jaded Faith VX30/Twin Tone/Silverado/Violent By Design/EV Trilogy, Salvation Loneclean, Synergy SLO

lebobl
RM50
Posts: 67
Joined: Fri Sep 27, 2019 1:57 am
Location: St. Louis, Missouri

Re: RM4 switching problem again

Post by lebobl » Tue May 19, 2020 8:56 pm

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.
Randall RM4
Fryette PS2
Mesa 2x12 Recto Cabinet w/ Celestion V30s
Modules: Jaded Faith VX30/Twin Tone/Silverado/Violent By Design/EV Trilogy, Salvation Loneclean, Synergy SLO

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