20 Most Recent Marshall MG100HDFX 100-Watt Amplifier Head Questions & Answers

If he KNEW it "just needed a fuse", why didn't he "just" replace it.
Could have sold it for a lot more if it worked,
The fuse is on the end of a circuit board right behind the power transformer, It should be a little glass fuse.

Marshall... | Answered on Oct 04, 2018

You might need to take it to a retailer that has guitar equipment they should be able to solve your problem or have your answer

Marshall... | Answered on Apr 29, 2015

Output transistors, or output transformer.

Marshall... | Answered on Feb 25, 2015

Don't replaced anything until you jumper the power amp in jack to the preamp out jack [or effects send jack to the effects return jack]. There may only be oxidation in the contacts of these jacks. If the normal sound level comes back-either clean the two jacks or have them replaced.

Marshall... | Answered on Nov 23, 2014

Quick suggestion,
Often it is the socket, usually wired to back panel.
Remove chassis, clean sockets, re-solder both ends, on some Marshalls wires soldered to pins on PCB, re-solder pins as well
Experience has shown this will fix 99% of this kind of problem.

Marshall... | Answered on Nov 09, 2014

Try cooling or warming it to see if it stays on for more time(for cooling) or lower (for warming)...
If it does maybe the final stage of amplification (havent seen the scematics to tell you the exact component) must be overheating and stop its operation for safety and don't burn itself...
You should check the power supply for correct voltages and if they are correct change this chip with a new.
DONT change the IC before checking the psu because it may broke the new one too..

Marshall... | Answered on Nov 02, 2014

are you running straight off your amp with head phones? Or are you using the headphone jack as a stereo output? if just headphones. check the cord for a volume control. very common these days to have that be there. if there isn't one, check your connection so it's tight. and there will be a master volume on your amp. feel around the back panel.. they tend to blend in

Marshall... | Answered on Apr 29, 2014

it sounds like something internal on the foot switch is shorting out (or a lead wire has come off) or some where in that line , it has been severed. you can check continuity with an ohm meter. butfirst open the foot switch and just give it a visual to see if any leads are severed. you may just need to solder it back. - foot pedals get alot of winding up and unwinding. its common for something to disconnect. that would explain all the issues your having. good luck

Marshall... | Answered on Apr 24, 2014

Probably smoked the output IC(it is the chip mounted to the heat sink attached to the fan) which can be purchased from marshall directly or from one of their service centers. Also P-H216 sold at tubesandmore.com should work. No soldering required. Look at that IC(chip) to see if it looks burnt or has a crater on it which would indicate that that is indeed you bad component.

Marshall... | Answered on Apr 24, 2014

well believe it or not. a wood block is not a bad idea. ive done it myself. it is non conductive, so you won't short anything out. to answer your question, a circuit board is layed out in several levels. not just what you see on the surface. so your problem could be internal on that particular board . So when you bend it, it then makes the connection it is suppose to. Weather it be a ground or it completes a circuit. You can use the board method , or contact the mfr and purchase a new board. Which if you choose to do that, know that handling and installing that board , you want to make sure you release any static electricity from your body before doing so. You don't want to short out the board before you get a chance to see it work.

Marshall... | Answered on Apr 24, 2014

Try inserting a patch cable(or any 1/4" to 1/4" cord) into the effects loop jacks on the rear of the amp. If that helps you have a dirty or bad jack. A little WD-40 works wonders on corroded/dirty jacks.

Marshall... | Answered on Apr 20, 2014

Output trasformer is common too replace. Best OT is made by Mercury Magnetics, Weber.......

Marshall... | Answered on Mar 30, 2014

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