Marshall mg100fx broken pot

Is is just the knob has broken (in which case, buy yourself a new knob and replace the one that's there) or is the potentiometer shaft broken too? That's a much bigger job, that involves pulling the whole amp apart and replacing the pot --- you need to get an electronics tech to do it.

Google
mg series knobs
to find replacements --- they just push on.

All i can suggest is to use electrical contact cleaner on it from the inside. But you,ve already done that. And i would imagine that the master volumes will be the same to, Harry

Disconnect from the mains.
Unscrew the four screws in the top
Slide out the chassis
Remove the knobs
Unscrew the pot nuts
Unclip/unscrew the PCB
Unsolder the pot
Solder in new one.
Re-assemble in reverse order
Strongly suggest you youse a better quality pot
Also the treble pot tends to go on these, replace at same time
All the best, Chris

Usually with volume pots,the ratings dont matter. you can really buy then anywhere like guitar center,micro center and online. they're really cheap and well worth it.

Stop by Guitar Center and they carry spray product(s) made for cleaning "pots" IE: Blue magic, etc...

What did you spray it with? I hope NOT Deoxit or Blue shower as those wreck the pots by removing the lube.

Use CRC226 available in the electrical dept at Home Depot. Use the plastic tube by bending it so it can spray upward into the slot where the leads that solder into the board go into the metal can.

Spray a little in and work the pot... then try a little more and see if it improves the situation. If it does, treat all the pots the same. ALSO look for broken solder where the pot wires solder to the circuit board..

That should be a 320K pot. <br /> <br /> Here's a link to the schematic. <br /> <a href="http://www.ampix.org/albums/userpics/10003/MArshall_MG100DFX.pdf">http://www.ampix.org/albums/userpics/10003/MArshall_MG100DFX.pdf</a> <br />

The master control has one of two problems:

1. It is noisy. Get some CRC226 in the electrical dept of Home Depot and open unit and spray a small amount into the control through the back side where the leads go into the pot. You may need to bend the spout of the CRC226 can to get it into the slot. Turn the pot back and forth to distribute the product on the resistance element inside.

2. The solder of the leads of the control has broken. Resolder these leads.

There are many models of Marshal amps icluding 15Watt types.

First thing to try is to see if headphones have normal volume. If they do, then the headphone jack switch that connects the speaker is LIKELY bad.

If the headphones do not have any volume, LIKELY causes are:

1. Fried output power amp

2. Volume pot is broken or has bad solder joints to the circuit board.

It sounds like your volume control is dirty. You will have to disassemble the amp enough to get access to the volume potentiometer which is soldered to the circuit board. There will be a square hole in it that you can spray some contact cleaner into the control. Use only contact cleaner as anything else could damage the control. Use a small squirt and rotate the shaft. If this doesn't solve the problem you may have to replace the control. While you have it apart, examine the solder side to make sure all the solder joints are perfect especially those on the controls. A bad solder joint can also cause the same problem. Before you take the amp apart unplug the power with the amp on and the volumes turned down. This will discharge the capacitors so it will be safe to work on. I hope this helps.