Hafler G-150 amplifier fried N-channel MOSFET

Alex26C

Member
2016-02-03 12:02 am
I have an older Hafler G-150 solid state guitar amplifier that smoked a k1056 mosfet the other day when I first turned it on after it had been sitting some time. I found a 2sk1056 ( which I'm told is the same as the K1056) and ordered it online. My question is could the large 6800 uf 63 V power supply filter caps be the culprit due to old age? I haven't put a meter on them yet so I don't have any readings as to their health, but physical inspection looks fine though. Are there any other things I should be checking while I'm at it? Thanks in advance.:confused:
 

Alex26C

Member
2016-02-03 12:02 am
I've checked around but I'm not finding one for that specific model. If it helps, I can post a pic of the inside of the amp and the damage to the transistor. It made a hissing sound when I first turned it on followed by white smoke pouring out of the vents. I've checked it out pretty good and the only physical damage I see is the burnt MOSFET and a corresponding 5A fuse on the same channel.