problem with RM4 repair - need some advice

[feefop]

So I'm having a problem with the RM4 - master volume cuts out/fizzles out. I tap the unit and sometimes it happens as well. I'll fiddle with a module volume control, and after cranking it a couple of times, the RM4 master volume will kick back in. Seems to happen after the unit warms up.

So I took it to a shop (randall authorized repair center), and the tech was unable to repeat the problem. Here is what he did:


RE-FLOWED SOLDER CONTACTS ON MODULE ASSY
CLEANED ALL POTENTIOMETERS
1.00 ELECTRONIC REPAIR BENCH RATE PER HOUR 96.00 96.00
ALL FUNCTIONS TEST OKAY
Shipping and Handling 26.07
NOTE: CHECK MASTER VOLUME - AFTER 1/2 HOUR OR SO SOUND CUTS OUT
QTY Description Price Tax Amount
$96.00

So I paid $96 for nothing, really. I'm not sure why he couldn't find the problem.

Anyways, what can I do here? Go back to him and make him figure it out? Do a chargeback on my CC? He's not a bad guy, but at the same time I need to have a problem fixed and I don't feel I should have to pay more.

Need a little guidance if anyone has faced this situation before.

thanks :wink:

 

[Jaded Faith]

So if I read that correctly, he gave it back to you stating it would act up after a half hour? If so, that's BS by my standards. I work on a lot of amps here in my shop and nothing leaves here like that. I personally would be holding him accountable.

Regarding your problem, when you say you crank it a few times and then the Master kicks back in do you refer to the module or RM4 volume knob? If it's the RM4's, it sounds like it could be that pot failing.

Let's start there and see where it goes. I have mine open on the bench right now, so I may be able to give some pointers as we go.

Rob

 

[feefop]

No, actually I told him that the sound cuts out after 30 minutes or so. He couldn't repeat the problem.

Anyways, he did some basic work on the unit, but didn't solve my problem. Its not really practical to take it back to him, as it would cost me $25 each way either shipping or driving.

How can I approach him asking for my money back? what should I say specifically?

regarding the volume, the sound will just fizzle out. I'll work a module volume and it will kick back in. Now, I'll work the RM4 master volume and it kicks back in....can be either the module or RM4.

thanks

 

[Jaded Faith]

Thanks for clearing that up. I might suggest calling Randall and explaining the entire story. If the guy is a approved service center, they can probably do something to make things right and may even reimburse you. Start there before anything else.

 

[m0jo]

Could be a failing pot or a dirty jack (I've had similar experiences with the latter).

Does it act the same on every module?

And does a loud signal bring it back? (ie. really digging into the strings or using a booster).

If it does it's probably the jack, if only physical contact brings it back, I'd say it's a failing pot or broken/cold solder joint (on the pot) perhaps?

 

[feefop]

Could be a failing pot or a dirty jack (I've had similar experiences with the latter).

Does it act the same on every module?

And does a loud signal bring it back? (ie. really digging into the strings or using a booster).

If it does it's probably the jack, if only physical contact brings it back, I'd say it's a failing pot or broken/cold solder joint (on the pot) perhaps?

Each module has the same problem. Here is a you tube video of the issue:

http://www.youtube.com/watch?v=hlpp2Jwyawc

 

[Mattfig]

Could be a failing pot or a dirty jack (I've had similar experiences with the latter).

Does it act the same on every module?

And does a loud signal bring it back? (ie. really digging into the strings or using a booster).

If it does it's probably the jack, if only physical contact brings it back, I'd say it's a failing pot or broken/cold solder joint (on the pot) perhaps?

Each module has the same problem. Here is a you tube video of the issue:

http://www.youtube.com/watch?v=hlpp2Jwyawc

Yep, sounds like the problem I had/have occasionally too....Clean all your jacks really well with deoxit and some light grit sandpaper - even the ones you may not use...Especially clean the inputs on front and back...Lastly, open her up (unpowered) and physically check connections that you can easily reach...You can even clean those too but probably unnecessary....It seems the jacks on some RM4s must get pretty funky pretty easily....If you've already done this, try once more...I know that ain't the best advice but it is how I solved my issue...Which, after watching your video, was exactly what I was experiencing...

 

[Jaded Faith]

Working all the jacks with Deoxit sprayed on a guitar cable was going to be my suggestion after seeing your video as well. It's great preventive maintenance and I do it on everything 1-2 times a year, pedal board included. That sounds like intermittent contact is being made somewhere.

 

[Daryl]

Yeah guys. Clean those stinking jacks. I had a Tech 21 amp years ago that would cut out and eventually just wouldn't make any sound. I asked customer support and they told me to clean the effects loop output jacks. It turned out that the dirty jacks were actually responsible for killing my sound.
Works fine now. I could have kicked myself for not trying that first.

 

[tuna141]

Have you tried banging the side of the RM4 when the output is low? Does it momentarily fix the problem?

It may be a cold solder joint making a poor connection in the signal path. When you turn up the gain pot on the module, it allows more or current to flow through, which bridges the poor connection. I'd try touching-up the solder joints in the RM4 and see if that helps. Also, make sure any socket components and all connectors are fully seated - I'd also try re-seating them to remove any oxidation on the connectors.

 

[Daryl]

Have you tried banging the side of the RM4 when the output is low? Does it momentarily fix the problem?

It may be a cold solder joint making a poor connection in the signal path. When you turn up the gain pot on the module, it allows more or current to flow through, which bridges the poor connection. I'd try touching-up the solder joints in the RM4 and see if that helps. Also, make sure any socket components and all connectors are fully seated - I'd also try re-seating them to remove any oxidation on the connectors.

OOh...That's a good one. I'll have to make a note of that as well. I think Mojo touched on that a little in a previous post on this page. So simple yet so easy to overlook.