bigbang2400.1

[timwebb]

i bought this amp to fix. the issue was one irf1010e had a broke leg and put it into protect. but i cant get any audio from it period. i have rail pos-neg voltage and 13.8 pos and neg on the opamps. any thing im missing?

[Perry Babin]

Do you have rail-rail oscillation on the output transistors?

Do you have the master/slave switch set to master?

[timwebb]

its set to master. and just check and i have no rail-rail oscillation.

[Perry Babin]

Does the amp go from protect to normal operation after a few seconds?

[timwebb]

yes.

[Perry Babin]

I'd suspect one of the 3 transistors along the top edge of the driver board on the end nearest the power supply. You'll have to check for leakage as well as for open junctions.

[timwebb]

ok. thanks!

[timwebb]

one of the 1277 have a low ohm reading from the rest. also. what is the diode in zd5? i keep forgetting?

[timwebb]

i cant find the kta1277 transistor. i was looking at 2sa1156 to replace it

[Perry Babin]

I haven't checked the one on this board (which is a modified version of the more common driver board) but it's likely a 5.6vZ. It should be marked.

I'm assuming that you're referring to the one on the lower left corner of the board near the 10k resistor. On the photos I have, it appears to be a ZD6 but the silkscreening isn't very good.