Kirk UK

Hi guys,

I'm new and hoping someone can help me. I've got a Marshall 5210 which I've had since about 1996. I have no idea when it was originally made unfortunately. Anyways, it's always had this intermittent problem where the sound would go really quiet and lose all bass - it basically becomes a real Tinny sound like I'm playing through a mobile phone or something!

Usually works again if I unscrew the top, pop all the workings out and spray a bit of WD40 around the jacks and knobs etc. But not always - sometimes it's gone back to normal just by whacking the damn thing real hard on top.

Anyways, lately the problem has been getting more regular and recently, during a jamming session, it developed the problem and has not sorted itself since. No matter what I try with my limited knowledge! Basically all I know is it's not valve - 'cos it's a solid state amp! lol

Any suggestions or am I going to have to send it off to Marshall - or am I better of just retiring it?!

Any help would be most appreciated! I need to play my guitars again!

Marshall Amps

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bigragu63

Hi Kirk,

I have a 5210 that I use as a backup for my 4010 tube combo. It had a problem with a bad hum, which ended up being a bad solder joint on the circuit board. The intermittent problems you've had, increasing to the point of failure, sounds like a bad solder joint or a faulty component.

If you haven't already, I would pull the chassis out of the cabinet, remove the board, and inspect all the solder joints closely. While you're at it, look for any components that appear to be burnt.

In order to pull the chassis out of the cabinet, you'll have to unplug the wires that go to the reverb tank, and take them out from under the clip on the side of the cabinet (if your amp still has that clip), and unplug your speaker wires. I write a "R" and "B" on the tank so I remember which connectors the red and black wires plug onto. Now you need to remove the board, so you can look at the solder joints on the underside. To remove the board, if I remember right, you'll have to remove all of the knobs, the nuts that anchor the potentiometers to the faceplate, and the nut on the input jack. Then remove the screws that mount the board to the standoffs inside the chassis. A bad solder joint will usually look darker than the rest, or even burnt. Sometimes, they may not even look too bad, but under a magnifying glass you can see the lack of contact between the lead of the component and the solder itself. Usually, by the time it gets bad enough to cause a failure, it'll be obvious.

Good luck!

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