RM4 Problem is back

[Mattfig]

OK, I couldn't find my old thread about this....But my RM4 featuring my clean modules is acting up again....Basically it operates properly but then has significant signal degredation - lightly distorted and weak...If I turn off the power and flip it back on the problem temporarily goes away...I haven't timed it to see if it's a specific interval but it seems to be happening more often again...

I've changed and tested each tube and know it isn't them 'causing this? transformer????

I also cleaned connections and tried using front and back inputs...Didn't help...

Any help is appreciated!

 

[bansheeburner]

I know you said you checked the tubes but I had this same thing happen to me with eh tubes. As soon as I changed them it went away, but now you've got me thinking that I might have something else going on.

 

[Mattfig]

I know you said you checked the tubes but I had this same thing happen to me with eh tubes. As soon as I changed them it went away, but now you've got me thinking that I might have something else going on.

Same for me... When I change tubes the problem goes away for a bit...But check the tubes you pulled in another unit....Mine were never fucked...They were all just fine....

Hope neither of us is looking at a serious problem man... :?:

I seem to recall mojo having some idea of what could be up....Hope he reads this....Let me use my telepathic skillz to summon him here....Thinking, thinking,Thinking, thinking,Thinking, thinking,Thinking, thinking,Thinking, thinking,Thinking, thinking,Thinking, thinking,Thinking, thinking,Thinking, thinking,Thinking, thinking,Thinking, thinking,....OK message sent...And I think I may have shat myself during that serious concentration...Telepathy and bowel movements are unfortunately related...Those of you who are enlightened will know that someday....

 

[Mattfig]

OK, so I usually jump around while playing between modules...Well tonight I just played clean....The problem comes and goes....Powering down always means it'll power up right to start....But it's almost like you can push it back to life...Meaning hitting the srrings hard at max volume seems to bring it back....Or it's coming and going and I just did that coincidentally....

Just an update...

 

[SacredGroove]

It only happens with the cleaner/low gain modules?

 

[chuckmehh]

SAME thing with my clean module in an RM100 though!

 

[GtrGeorge!]

Im no expert but...
it sounds like some capacitors. Cap charge up and then give off their charge..thats how they work.,When failing they hold a charge sometimes and sometimes dont. It sounds like your situation.
This is most likely in the amp not the modules. It does happen all modules,right?
GtrGeorge

 

[chuckmehh]

Im no expert but...
it sounds like some capacitors. Cap charge up and then give off their charge..thats how they work.,When failing they hold a charge sometimes and sometimes dont. It sounds like your situation.
This is most likely in the amp not the modules. It does happen all modules,right?
GtrGeorge

just clean...

 

[Mattfig]

Just to clarify....

It happens on all modules in that particular RM4...I break my RM4s up by category and the one having the issues just happens to house the clean tones I use...It would happen with any module, it just happens the one that houses the cleans...

The capacitor thing sounds about right as well as the assumption that the problem is with the RM4...

Anyone know a way to systematically approach this scene?

Thanks much!

 

[SacredGroove]

Just to clarify....

It happens on all modules in that particular RM4...I break my RM4s up by category and the one having the issues just happens to house the clean tones I use...It would happen with any module, it just happens the one that houses the cleans...

The capacitor thing sounds about right as well as the assumption that the problem is with the RM4...

Anyone know a way to systematically approach this scene?

Thanks much!

Does it happen while you're playing or after you've stopped and then notice it after you've started again? During quieter/louder notes?

 

[Shinozoku]

Pick up some Xicon caps, of some SoZo's if you wanna try what I'm eventually gonna do an upgrade ALL the caps in a given amp.

Get the values you find in the RM4 and start swapping them!

 

[GtrGeorge!]

CAPS CAN KILL.
be careful..some caps store alot of jiuice...I would not tinker around an Rm4. Get a pro...somebody you can trust and they (with a schematic) can find the problem. Matt...youve spent a ton on modules..you can afford to spend a small amount making certain they are in a functioning rm4.
GtrGeorge
..and vote,ok?

 

[Mattfig]

CAPS CAN KILL.
be careful..some caps store alot of jiuice...I would not tinker around an Rm4. Get a pro...somebody you can trust and they (with a schematic) can find the problem. Matt...youve spent a ton on modules..you can afford to spend a small amount making certain they are in a functioning rm4.
GtrGeorge
..and vote,ok?

Good point...And of course I'm gonna vote!

 

[eedude]

okay, my 2 cents. FWIW...:idea:

Before you launch in and start wily-nilly changing out parts you need to isolate the defect to a particular subsystem (i.e. power supply, input stage #1, effect loop buffer circuit, module switching infrastructure) . You then take some measurements or perform other experiments to isolate down to the component(s).

You have to be ready to rip you RM4 apart enough so that you can get to all the circuits that can be in question. You need to have enough electronics knowledge that you can reverse engineer circuits (in a basic sense) so that you know what is what... you need to be ready for some home-brew debugging techniques, like tapping the signal off a points in the flow and run them off to another amp to be monitored...you should have some idea as to voltage values to expect at various parts of the circuit (i.e cathodes should at ~1V, plates are around 200V, switching logic uses 5V, etc...)

are you ready?

Btw, caps don't kill people, people kill people... or something like that I saw it on a bumper-sticker once...

 

[Mattfig]

I think I'm up for the challenge...But I do want to be systematic...So thanks....Before I tear into her I gotta do more troubleshooting...

 

[Mattfig]

OK, after playing around with this RM4 I have realized something potentially telling...

When the signal degrades I can snap it back by hitting the strings hard...Every module does the same thing...That must mean something....Of course I don't know what....Hoping one of you will...Something simple right???? PLEASE PLEASE PLEASE???

 

[Julia]

I hate crap like this. Have you tried hitting the unit on the side? That used to work with my old television. No. Don't do that.

Going into this and starting to change caps and resistors could be very time consuming since intermittent problems are almost impossible to diagnose, or you could take the shotgun approach and replace all of them -- make sure you've completely discharged the board before working on them. YOu'll probably never want to solder anything for the rest of your life.

 

[Mattfig]

I hate crap like this. Have you tried hitting the unit on the side? That used to work with my old television. No. Don't do that.

Going into this and starting to change caps and resistors could be very time consuming since intermittent problems are almost impossible to diagnose, or you could take the shotgun approach and replace all of them -- make sure you've completely discharged the board before working on them. YOu'll probably never want to solder anything for the rest of your life.

I'm hating it too! The fact that I can make a loud signal and the RM4 goes back to normal must mean something to someone here...I hope...I've opted not to start replacing a bunch of stuff just yet...Hoping someone here will have some experience with a similar issue....

 

[alboz28]

This may sound weird , but I had a Marshall head that did this very same thing years back and I replaced the power switch and fuse holder and it fixed it - Just throwing it out there

 

[Mattfig]

This may sound weird , but I had a Marshall head that did this very same thing years back and I replaced the power switch and fuse holder and it fixed it - Just throwing it out there

Thanks....Suggestions like that are worth a lot...I don't want to go to a tech and drop 200 or more dollars into him/her doing something simple like that....I check those connections at the very least...

Thanks!