Fender Frontman buzzes from time to time

Mysterry

Hello everyone,

I bought a Fender Frontman 15G second-hand. The problem is it is buzzing in a strange way. Most of time, it happens when I turn it on, even with no input. When turned off and on again, it stops.

And sometimes, when I play, buzz appears after a couple of minutes.

It appears with all the sockets of my house, and I tested them with a tester: it seems the sockets have a correct earth wiring.

I recorded it: http://sendvid.com/x4bhbuif

What could it be? And what should I do?

Do you think this could be a dangerous earth-related issue?

Thanks for your help!

57Deluxe

Sharp tap on the back sorts it!

Mysterry

Hey 57Deluxe, thanks for your advice!
But what do you mean by 'sharp tap' the back?

ICBM

Probably a cracked solder joint somewhere, quite possibly on one of the filter caps or something else related to the power amp, since it seems unaffected by the controls. Probably turning the amp off causes a voltage spike which makes contact, enough to keep it 'fixed' until it discharges completely the next time you leave it off for a while... or something like that. It could also be a fault *in* one of the filter caps, I've come across one like that before.

Very unlikely to be dangerous. Even if it was something to do with the earthing, it wouldn't be dangerous by itself, unless something else very unusual went wrong at the same time.

57Deluxe

Mysterry said:

Hey 57Deluxe, thanks for your advice!
But what do you mean by 'sharp tap' the back?

Just that - tap it hard with your hand on the rear panel - stops it!

you might also like this YT watch on dialling in... 

DJH83004

If a sharp tap on the back does indeed sort it, then it is more than likely a bad joint on the PCB, around the power supply area. There are two filter caps for the main +/-ve supply rails, plus two more for the zener regulated +/- 15 supply, I suspect one those is the culprit. Not sure if IC would agree with me on this but in my experience, the Frontman amps are not really cost effective to repair unless it is something very straightforward like a cabling issue. 

ICBM

DJH83004 said:

Not sure if IC would agree with me on this but in my experience, the Frontman amps are not really cost effective to repair unless it is something very straightforward like a cabling issue. 

Borderline - if it's just a solder joint or even a single filter cap replacement I'd probably do it, even though the amp isn't worth much more than the cost of the repair - even though the board needs to come out it's fairly quick if you're familiar with them. If it's anything worse or needs a lot of investigation it probably isn't worth it.