Is it possible the D11 zener is bad and not regulating even though it checks ok in circuit (diode check). It seems B+ is gett ing in somewhere.
D11 isn't a regulator here. It's used to shut the amp down if the input voltage is too high.
It's possible that it's leaky.
It's possible that it's leaky.
393 pin 3:
Removed D34 pin 3 still hi
Removed D7 pin 3 still hi
Removed D5 Pin 3 lo 494 outputting.
Can I assume D5 and D6 leaking?
Removed D34 pin 3 still hi
Removed D7 pin 3 still hi
Removed D5 Pin 3 lo 494 outputting.
Can I assume D5 and D6 leaking?
That would be a safe assumption but odd to have two leaky diodes in the same circuit.
Do the check as leaky out of the board?
Does the voltage on terminal 3 go to near zero with all other components back in the board except for D5/D6?
Do the check as leaky out of the board?
Does the voltage on terminal 3 go to near zero with all other components back in the board except for D5/D6?
Out of circuit D5 tests open and D6 is ok. Maybe testing open but leaking when voltage is present?
Yes with D5 and D6 out, and everything else back in, got a nice gate drive on the PS Fets.
Do not have these diodes so will have to order.
Yes with D5 and D6 out, and everything else back in, got a nice gate drive on the PS Fets.
Do not have these diodes so will have to order.
Looking at the photo of the board in post 1, it looks like D5 has a bump. I thought it was a dimple from molding/manufacturing but I can't see it on the other diodes.
You are exactly right on the bump on the diode.
Hey, I believe Q288 on the drawing is for over-current protection?
My board also has Q289 on the other rail. Would Q289 likely be a PNP complement to Q288?
Hey, I believe Q288 on the drawing is for over-current protection?
My board also has Q289 on the other rail. Would Q289 likely be a PNP complement to Q288?