Ampeg BA115HP Output and crackling/static

[ca7922303]

is that what you have now?

Yes, that is correct.

[ca7922303]

In post #65 you asked for 2 sets of measurements, first DC (no signal), the AC (signal applied). I think the post #68 are the 2 sets of results, though I am not 100% sure.
In post #47, he gave Q1 and Q4 DC voltages that did not agree with DC from post #68 (6VDC at TP10), although in post #47 the load may have been connected.

Yes, post#68 are the 2 sets of results asked for in post#65.

[ca7922303]

A person can make a mistake, measure incorrectly. So I asked again to specify the voltages between the base and emitter of these Q4 Q1, especially there are non-compliances.

Q1-B(-11.6vdc)E(-11.1vdc)
Q4-B(- 5.9vdc)E(- 6.5vdc)

[x-pro]

Check R50.
Check if +16V is present on its top pin.

[ca7922303]

Check R50.
Check if +16V is present on its top pin.

R50(+17/-5.8vdc)

[x-pro]

check Q3

[ca7922303]

check Q3

Q3(photo). Can't get to it without removing Q2/5/7/8. Can we skip Q3 and continue testing possibly for now?

[ca7922303]

Q3 is surrounded by that metal plate. Probes will touch it if I try to measure. Will have to remove it probably this weekend, if there's no way to skip over it for now.

[x-pro]

Measurement points.

Q3 doesn't even need to be unsoldered to measure its b-e

[x-pro]

Q1-B(-11.6vdc)E(-11.1vdc)
Q4-B(- 5.9vdc)E(- 6.5vdc)

The minus of the voltmeter is at what point?

[ca7922303]

Measurement points.

Q3 doesn't even need to be unsoldered to measure its b-e

This evening after work, I will measure Q3@R43/44.

[ca7922303]

The minus of the voltmeter is at what point?

Not sure I understand your question? I measured to ground.

[ca7922303]

The minus of the voltmeter is at what point?

Black(-negative probe) went to chassis ground.

[x-pro]

right?

[ca7922303]

Believe so