Fender Frontman 15G aux problem

[Bladerkeuh]

Hi, I can't find anything about this problem, so I post something on this forums since this site appears to be full of people who know a little something about amps
My problem's the next: this amp has an aux-input, which is a very nice thing, but when I plugged my Ipod on a few days ago, the amp started humming and then just died... I took the backplate off and saw that the fuse was blown, so I bought another one. When I put this one in the amp, it works, but only like half... it hums very much, and the led-light from the power switch only burns half its capacity...
Anyone who can give me some advise? Can I fix this on my own, or should I just buy another amp (which I'd rather not do...)

Thx in advance!

[Bladerkeuh]

Uhm, someone plz? :/

[Enzo]

You may have a bad filter cap, or perhaps the solder connection has failed under one of them. Alternatively it could be a bad power IC on the heatsink.

[Bladerkeuh]

You may have a bad filter cap, or perhaps the solder connection has failed under one of them. Alternatively it could be a bad power IC on the heatsink.

Thx for the reply! But I don't know a lot about electronics, so is this something I could fix myself or not? And what precisely should I do then?

[Enzo]

I have no idea what your capabilities are. This repair will require soldering parts on the circuit board no matter what. Might just need existing parts resoldered or it might need new parts. If you are not prepared to solder circuit boards, then you need to refer the repair to someone who can do that sort of work. And if it is not a simple solder job, any sort of diagnostic work will require use of a voltmeter and the ability to identify components.

[Bladerkeuh]

Well, I can solder, but searching the problem isn't going to work, that's why I posted something here thanks anyway, this did help me now it's only deciding whether I let someone repair it and probably pay a lot of money, or just buy a new amp... (definitely not a fender anymore, this is the 2nd amp that brakes this way...)

[Enzo]

If you can solder, the look on the main circuit board for two identical cylinders, probably right next to each other. I don;t recall if they are the kind that stand up on the board or if they lie flat. They will be the largest of a number of similar looking cylindrical parts. Look on the underside of the circuit board carefully at the solder that holds them in. If ther are any cracks in the solder, resolder them. For that matter, just resolder them anyway.

If you have some knowledge, i am describing capacitors. They will have a number on the side like 2200uf or 3300uf or 4700uf or similar.

You might just get lucky. Otherwise I would suspect your power IC, the five-legged thing screwed to the metal but soldered to the circuit board.

[radtekvp]

Repairing it yourself with little experience

If you are extremely observant and careful you can often spot where the problem is on some pcb (if the problem is indeed on the pcb). Resoldering can work - and cracked traces or solder joints are indeed a common simple failure cause for hums and such. The large electrolytic capacitors are also failure prone with time and temperature extremes. When they fail they often swell slightly - compare the tops of similar ones.

Be aware that things which are bolted in and/or screwed down often use very specifically-designed parts to assure good thermal contact and electrical isolation. Reassembling things in the wrong order will irretrievably damage most IC's within about a millesecond - after that you will smell the smoke.

The most difficult thing is to identify what the part is and how to find an "equivalent" because find the exact replacement is often impossible. Sometimes the burned out part has obliterated the part numbers. Sometimes there are no numbers at all - and sometimes so many numbers and symbols that it is difficult to know which is the one to search for. That is where the experience and knowledge come in - what will work and what wont.