circuit board help, please.

I know this is an amp building forum, but it looked like the best place to get an answer, so please bear with me.
I have a Marshall MG 50 amp. I've had it for years, it's definately out of warranty. It developed a problem and began cutting in and out volume-wise. Upon opening and investigating, the problem is this. There is a white plastic clip,for lack of a better word(I don't speak amplispeak) mounted on the circuit board. It's about 4" long and maybe 1/4" wide. There is a corresponding harness with 15-20 wires that clips into this. The problem is that it is loose or does not lock into the piece mounted on the circuit board properly. If I push it to one side the amp plays properly, but once it settles back in place it has problems again. I thought about reflowing the solder on the back, but I can't seem to get the circuit board loose from the amp so that I can flip it over to do that. Does anyone have an idea what else I might do besides take it to a tech? Thanks.

It sounds like one of the wires in the harness has a bad connection. Try to separate the wires enough to wiggle them one at a time to determine which wire is the problem. Then resolder that wire.

Moving the clip is not fixing the amp. The clip was supposed to keep the connection from failing but that has already happened.

Thanks, Sizzler. The amp is at church right now. I wrapped some tape around the wires and ran that to a screw in the frame, which holds the clip to one side. A temp fix, but I needed the amp to work. I'll bring it home tonight or Sunday and see what I can do. One question: I assume you mean to resolder where the connection is soldered underneath where the clip is soldered to the circuit board? If so, I'm going to have to figure out how to get the board loose. I know it should unscrew, but there are two boards, one atop the other, and a lot of connections between the two that I'm not sure how to seperate, or put back ogether. I'll have to study it a bit.

gitlvr, if you have to disconnect those connecting wires, label them and/or take some digi-pics so as to be able to get them reconnected properly. Taking the boards out????
IT should be relatively simple and straightforward. There will be screws and/or plastic standoffs. The plastic pieces will be the type that fit through a hole and have to be compressed for removal. that, and 'de-nutting' all pots and jacks shuold get things apart.
I can always take something apart..getting it together correctly is the harder part of the job.

I can always take something apart..getting it together correctly is the harder part of the job.

LOL! Thanks, Wally, that's my concern as well.

If you've determined that the amp works with some pressure on the ribbon cable, I assume you've opened the thing up.

Just in case you've not been assaulted by safety warnings yet, please be aware that there are charges insite that amp that can kill you dead. I'm not talking just wall current here. Those tubes run on multiple hundreds of volts, and the filter capacitors store enough current to knock you across a room - which has happened to people.

If you're not 100% confident that you're being as safe as possible around those amp guts, get someone to help you out. It sounds like the job wouldn't be too bad unless the cable connectors are really shot.

A job best done with one hand tied behind the back, eh, Ben? PRoviding a path across the heart by having both hands in the 'pie' is when it becomes something dangerous more than something painful.
My apologies for not providing a warning, gitlvr.

Thanks, Ben, but the tubes in this amp are harmless(yes, that's a pun).There are none. But I very much appreciate the warning. I know enough from lurking in amp forums to know an open tube amp can be deadly, plugged into the wall or not, and would never attempt to fool with one. This amp is a cheap transistor one, but I actually love the thing. And Wally, no need to apologize. I greatly appreciate your help on this.