GK 1001RB 2 - Problem passing self check

[The Dude]

...... or maybe a shorted Q6.

Edit: response to post #14.

[nickbme07]

I was getting the voltages on D14 without the preamp connected yesterday.

[nickbme07]

But for reference, the preamp board is the 206-0251-A3 and above voltages were done today with the unit completely assembled

[nickbme07]

Im seeing the -100v on the R21 (and slowly goes down) and -100v on all 3 pins of Q6

[nickbme07]

-1.7v on R5 so not coming from Q1.

[clintronics]

Gk 1001ii 206-0260-a7

[nickbme07]

Great! Thanks for that, clintronics!!

[nickbme07]

For reference, you can also find my revision of the preamp board (206-0251-A3) on page 12 of the pdf here: https://elektrotanya.com/gallien-kru.../download.html

It seems they goofed the schematic between the power and pre boards with improper labels (J8's on power side pcb, J2's on preamp pcb..)

[g1]

-100v on all 3 pins of Q6

Does Q6 measure as shorted?

[nickbme07]

I will test again when I get back to it later today, but tests in circuit with diode function on DMM showed no shorts.

[nickbme07]

Q6 out of circuit measures with DMM diode test:

E to B, .659
C to B, .653
E to C, OL

B to E, OL
B to C, OL
C to E, OL


I took Q5 out of circuit and tested it as well..

E to B, .660
C to B, .656
E to C, OL

B to E, OL
B to C, OL
C to E, OL

[nickbme07]

Any other to pull to test while I have her out?

[nickbme07]

Q1 is also ok..

.656 and .662, rest OL

[nickbme07]

If I lift a leg on R12, the -100v that is detected on all those spots abovr go to 0v. Could something be going on with Q1? It tested good in circuit but I haven't pulled it yet.

[g1]

I think it's more likely that the protection circuit is just doing it's job.
At the upper right corner of power amp schem., there is the 'fault' line going into Q19. That 'fault' line comes from the collector of Q15 in the top side of pwr. amp.