Marshall AVT 100 TDA7293 chip

[geraint evans]

I have an avt 100 which has served me well untill now
The original problem was the TDA7293 chip overheating and smoking , the fixing screw was loose , tightened screw, amp was working ok for a while although the tone of the amp was compromised
Then there was smoke coming from diodes d217 & d218 , turned amp off . turned amp back on again and fuse blew , and d217 & d218 where definitely burnt out , when removed they crumbled to bits , are these problems related, or are there two separate problems.
when tightening the screw on the tda7293 ,could this possibly
cause the ic to short out to the heatsink ?.( i should mention the circuit board was pretty dirty under the vent where d217 & d218 are located on the top of the amp and was cleaned up during the general maintenance i was caring out )

Geraint

[micri5446]

hi....inho i think that the 7293 was heating up over time from not being cinched to the heatsink tight and when you made it tight and ran unit, the current draw was way up from the ic being damaged. that in turn took out diodes. change all(7293 and diodes) and you should be fine. one good thing about SS is some circuits are more forgiving than tube circuits. good luck
peace...........................mike