20 Most Recent Marshall Amplification Marshall JVM410H 4-Channel Guitar Amp (with Footswitch) Questions & Answers

Are you using a single coil pickup guitar (Strat or Tele)? If yes, then this is normal depending on how much gain is dialled in.

Test if it does it with the guitar cable unplugged from the amp. If it does, then it is time for servicing... If not, then you have a system grounding problem and the guitar cable is "leaking" signal into the amp. This can happen even if guitar is NOT connected.

Likely destroyed the rectifiers AND the filter capacitors. Replace the capacitors and the rectifiers. There are a lot of them. There are fuses so some of those may have saved some parts.

D10 through D14 and D16,D17 and D20,D21 Some of these may have survived so test each.

C51 and C52, C26,C34 probably gone. Check the Bias supply is working at expected bias voltage.

Your schematic: http://elektrotanya.com/marshall_jvm410.pdf/download.html

https://www.dropbox.com/s/6spu98r39t2wvcr/Marshall%20G30RCD%20Schematic.pdf

First check the preamp valve in that curcuit

Hi. Doesn't look like it as the speaker is a 4 ohm one and the head needs at least 8 ohm as far as I can see.

https://www.manualslib.com/manual/99237/Marshall-Amplification-Mg15msii.html

Make sure speaker cable works and is connected then check fuses. If it has a master volume, make sure it's turned up.

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.

What type of Marshall, please? First of all, control the fuse and let me know.

clean switch connections

Does anything happen while you turn the knobs on the amp? I had a similar problem with a yamaha amp. It turned out a couple of knobs went bad. Soldered new pots and it works fine for me now.

No, the ATV50 head is rated for 4 ohms total. Using both 4 ohm cabinets at once will fry your amp. Your only option would be to rewire your cabs internally to 16 ohms each by connecting the speakers in parallel, but that would cut your amp's power in half.

No, the ATV50 head is rated for 4 ohms total. Using both 4 ohm cabinets at once will fry your amp.

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