Amp Hum?

[maikman]

My amp (fender frontman 15) just started to get a really bad hum to it today. Ive played 3 different guitars through it so I know the guitar isn't the problem, and 2 different cables so I dont think its that either. I noticed that if I touch the metal part of the handle and my guitar strings at the the same time the humming stops. Any idea on how to fix this?

[curtisa]

Broken ground connection somewhere? Do you have a multimeter? Can you measure bewteen the earth prong of the mains lead and the chassis of the amp to make sure there is continuity between the chassis and earth? How about measuring between the cable shield and the chassis?

Strictly speaking the shield of the guitar cable should be grounded via the amp, and if you have a hum that disappears when you touch the strings and amp handle at the same time you probably have a break somewhere in the earth circuit. Open up the amp and see if there are any wires that have broken free, or that appear to be about to break free.

[Mike Sulzer]

Remember also that broken grounds can be a health hazard. As Curtisa suggested, start by checking the "third prong" connection to the chassis. Do it soon.

My amp (fender frontman 15) just started to get a really bad hum to it today. Ive played 3 different guitars through it so I know the guitar isn't the problem, and 2 different cables so I dont think its that either. I noticed that if I touch the metal part of the handle and my guitar strings at the the same time the humming stops. Any idea on how to fix this?

[maikman]

I figured it out last night and forgot to post. I opened up the amp and checked out the main board. Looks like between the heat and the vibrations one of the copper tracks printed on the board came off and shorted out on a capacitor close by. The inside of the amp had a weird smell and there was a burn mark right by that capacitor. The track was burnt away so I soldered a jumper wire between the two points where the track used to be and its all good now.