MK II C+ Master Volume issue (cuts off)

[Buster Leggs]

When playing the Mk IIC+ the amp just cuts off, clean channel or lead doesn't matter ( power light stays on ). When I flip it to stand by with a note ringing, I hear it kind of come on as it fades to off ( for lack of a better way of putting it ) same as my other c's fade off when you hit stand by with a note ringing. When I rotate the master volume back and forth I can get the amp to come back on again, sometimes it stays on sometimes it cuts off again and I need to repeat the knob rotate thing again. There isn't a dead spot in the master volume knob per say and there isn't any static when turning it up or down. It doesn't matter if knob is pulled or not and it doesn't matter if its on class a or ab. Would cleaning the pot even help? This seem like it's something other than a dirty pot to me although I'm not very knowledgeable. If you've heard of this before please advise me. If someone thinks cleaning the pot would solve the problem could you please tell me how to do it and what to use. Any help or advice would be greatly appreciated. THANK YOU !!!

 

[JOEY B.]

You might be losing the signal at the "effects return" jack. Try running a patch cord from the FX send to the FX return jacks. It could also be a flaky V1 preamp tube.

 

[dodger916]

You might be losing the signal at the "effects return" jack. Try running a patch cord from the FX send to the FX return jacks. It could also be a flaky V1 preamp tube.

What he said.... ^

 

[Buster Leggs]

Thanks guys, patching the effects loop did the trick. What dose one do to fix a signal problem at the effects return jack. If I was going to keep it for sure I would be ok with patch cord but I'm thinking I might sell it and I can't sell it like that. Is this something that's easy to fix?

 

[JOEY B.]

Thanks guys, patching the effects loop did the trick. What dose one do to fix a signal problem at the effects return jack. If I was going to keep it for sure I would be ok with patch cord but I'm thinking I might sell it and I can't sell it like that. Is this something that's easy to fix?

It might be dirty contacts within the FX return jack. If this is the case, contact cleaner will be your friend. If someone has left a cord plugged into this jack for many years, you might have to bend the contacts, or better yet, replace the jack.

 

[gts]

Thanks guys, patching the effects loop did the trick. What dose one do to fix a signal problem at the effects return jack. If I was going to keep it for sure I would be ok with patch cord but I'm thinking I might sell it and I can't sell it like that. Is this something that's easy to fix?

It might be dirty contacts within the FX return jack. If this is the case, contact cleaner will be your friend. If someone has left a cord plugged into this jack for many years, you might have to bend the contacts, or better yet, replace the jack.

+1
It's a simple fix.

 

[Buster Leggs]

Thanks guys, patching the effects loop did the trick. What dose one do to fix a signal problem at the effects return jack. If I was going to keep it for sure I would be ok with patch cord but I'm thinking I might sell it and I can't sell it like that. Is this something that's easy to fix?

It might be dirty contacts within the FX return jack. If this is the case, contact cleaner will be your friend. If someone has left a cord plugged into this jack for many years, you might have to bend the contacts, or better yet, replace the jack.

+1
It's a simple fix.

I totally trust you when it comes to these amp, both of you have given me good advise in the past. So to understand what you're saying, I'm to clean or replace the part that, when the amp cut out, I plugged a patch cord into from FX send, that made the amp work again. In my simple mind that would indicate that the FX jack is working properly. When you guys are referring to contacts within the FX return jack I'm thinkin you're talkin about the 1/4 inch female switchcraft jack installed in the back of the chassis that says return to the left of it. Sorry if this sounds as redundant to you as it dose to me. I've got a new jack to put in. And if you're saying put it in, I'll put it in tomorrow. And I realize worn components effect these amp in ways only a seasoned tech can understand at times. So if yall say you believe that's the fix, I'll go with it even though I don't really get it. Mostly what I know about these amps, is that I don't. But at least I know that. THANKS GUYS

 

[JOEY B.]

Take some contact cleaner and spray it on the end of your patch cable. Then insert and remove it from the FX Send and Return jacks. Repeat this process about 3 times. This may do the trick. 8)

From the Mark IIC users manual: "For weaker incoming signals, the Effects Return can be used as an input and then the Graphic
would be functional. For Effects Loop use the jacks Mounted on the back panel. The Effects Return Jack
will interrupt the signal flow while the Effects Send can be used as an output without affecting signal flow.
If your Boogie should ever lose power or die out, always first run a cable between the two Effects Jacks
before proceeding to test tubes, etc., as such a problem could likely be caused by faulty switch contacts
in the Effects Return Jack."

 

[Buster Leggs]

Thanks Joey and gang she's ticking like a $50,000 watch. Suppose I could have caught that one by READING THE MANUAL. My faith in my ability to diagnose and fix is getting better (slowly)........Actually I've only asked questions and did what you've said, but getting braver. Time for me to get into the garage and look for that solder gun thingy, got some mods I've been meanin to do. :lol: