I've had the amp for about 20 years, but haven't used it much, one reason being this volume problem that began early on. Took it to music shop a year or so after buying it expecting tubes to be the problem and changed, but wa told there was nothing wrong with it. I've tried different guitars on it and it's still the same, so has to be a problem with the amp (which seems obvious). Hope you can help. Cheers, Karl
Most likely cause for this is an intermittent potentiometer. Check to see if any of them are mechanically loose as this is a sign that they have been damaged and could have cracked the wiper surface inside the pot causing this problem. Alternatively, any switch that controls any gain setting could also be intermittent or dirty. Gain of the amplifier should be stable, but is controlled by the feedback and signal injection at the pots so that is where to look first. Good luck, as intermittent problems are tricky, but sometimes better than no function at all which can be more costly.
SOURCE: Amp goes quiet after working fine for about 15-20 min.
If you are not a tech, I suggest you send it to one. If you are, after signal-dropout spray output transistors (one at a time) with component cooler (freeze spray). If still no results, go to the other transistors & IC's. Chances are that will pinpoint faulty component.
SOURCE: my guitar won,t play threw the amp lots oof static
The things to check arre FIRST the cable. These often have breaks or bad connectors. Replace with known good one and try it.
Next are the jacks on the guitar and the amp. These go bad and wiggling the KNOWN good cable at each end will flag which or both being bad.
Next are the switches and potentiometers in the guitar. Use some CRC226 sprayed into the pot and switch contacts... use sparingly...
The key is to find which thing or things are bad.
SOURCE: problem of marshall g80rcd, volume drop when i play
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.
Testimonial: "thx alots, i did try to clean it by blasting air on it, but i just not really sure. i will give another try. thanks for your quickly response. "
SOURCE: Hi, I have a Marshall 8240. The Reverb output
probably the reverb tank These coils are very thin and tent to break easily
As an electronics tech for 40 years I have spent half of those years reparing the damage done to electronic equipment by WD40. It is a great product when used in the correct situation. When it comes to cleaning controls in amplifiers etc the correct procedure is to apply a contact cleaner to flush out any dirt then apply a contact lubricant. WD40 contains minute graphite particles as well as corrosive chemicals. Between the two they swiftly render the controls to the bin.
WD40 great for unlocking rusty screws etc but never use it in electronic gear.
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