Hi wondered if anyone could give me some advice about the possibility of fixing my marshall MG15CDR which blew up this morning. When I switched it on it emitted a constant loud low hum. I left it on for about 1 minute while I fiddled with the controls and then noticed smoke coming from the back of the unit. I switched off and removed the control chassis and looking at the board I can see a burn around the pins of the op-amp. It has burned the board a little but the tracks are ok. I believe this is a LM1875 based amp. Is it likely that I can just replace this chip to repair or is it likely something else is wrong? Thanks.