Ampeg B2R no sound

[pontiacpete]

This amp is powering up and I have traced a signal to the output transistors but nothing is coming out of the speaker jacks and nothing from the either effects return jacks, from the sends jacks there is signal. Is this a problem with relay near the output jacks?

Ampeg B2.pdf

[g1]

Do you have any DC at the TP11 ? The relay circuit will protect if DC or overheating.

[Helmholtz]

See if you have continuity (zero Ohm) between TP11 and TP12 with amp powered.

[J M Fahey]

So you have signal at TP11 but not at TP12?

Any DC present on TP11?

DC would open relay connection, or simply relay is malfunctioning, what voltage do you measure across its coil?

[pontiacpete]

There’s no DC at TP 11.. when measuring across the 1N914diode D19 I get 1.4k. I guess that’s the coil.

[x-pro]

Is there a "Line out" signal on XLR?

[pontiacpete]

No signal on the line out

[x-pro]

Is there a "effect send" signal on TP3?
And on R1 after "effect return" ?

[x-pro]

And on pin 7 IC3 ?

[The Dude]

Do you get DC voltage across the relay coil? If you get proper voltage there, it would eliminate protection circuits. If the coil has proper voltage and the relay switch isn't closing, you have a bad relay.

[x-pro]

If there is no signal at the linear output, how did you manage to trace it to the output transistors?

[pontiacpete]

There is voltage on the coil. 60vdc on the supply end and about 30v on the other. Signal is on the top end of R52. I tried touching a wire from r52 to the output jack and there’s sound to the speaker. It must be the relay,no?

[x-pro]

At the base of Q23 there is a capacitor C20. What is the voltage on it?