Ampeg BA115HP Output and crackling/static

[g1]

Seems good so far. With 0.27VAC at TP12, what does TP10 measure?
What are DC voltages for E,C,B of Q4 and Q1 ?

[ca7922303]

Seems good so far. With 0.27VAC at TP12, what does TP10 measure?
What are DC voltages for E,C,B of Q4 and Q1 ?

TP10(0.09vac)
Q1-E(-2.6vdc)C(-57vdc)B(-3.1vdc)
Q4-E(+2.4vdc)C(+57vdc)B(+2.9vdc)

[x-pro]

What g1 is asking you for are the DC voltages of the transistors.

[ca7922303]

What g1 is asking you for are the DC voltages of the transistors.

Thanks for catching that, edited post.

[g1]

TP10(0.09vac)

This was while TP12 had 0.27VAC? Try again. There should be around 2.5 times more signal at TP10 than TP12.

[ca7922303]

This was while TP12 had 0.27VAC? Try again. There should be around 2.5 times more signal at TP10 than TP12.

Checked it again and with TP12 @ (0.27vac)
TP10 is(0.09vac).

[g1]

Check resistance of R22 and R26. Check that resistance from U5 pin1 to pin5 is 1K.
Check that DC volts at U5 pins 4 and 8 are -15V and +15V.

If all that checks out, replace U5.

[ca7922303]

Check resistance of R22 and R26. Check that resistance from U5 pin1 to pin5 is 1K.
Check that DC volts at U5 pins 4 and 8 are -15V and +15V.

If all that checks out, replace U5.

R22(1k ohms)
R26(46 ohms)
U5 pin 1-5(1k ohms)
U5 pin 4(-17vdc)
U5 pin 8(+17vdc)

[ca7922303]

Check resistance of R22 and R26. Check that resistance from U5 pin1 to pin5 is 1K.
Check that DC volts at U5 pins 4 and 8 are -15V and +15V.

If all that checks out, replace U5.

Ordered 5-ne5532($5.81 free delivery) from Amazon. Wednesday delivery

[x-pro]

What is the value of C10 on resistance! directly on the board without unsoldering it
Instead of NE5532 you can temporarily put any dual amplifier such as 4558,4560,4580, lm158,258,358,2904 series.

[ca7922303]

What is the value of C10 on resistance! directly on the board without unsoldering it
Instead of NE5532 you can temporarily put any dual amplifier such as 4558,4560,4580, lm158,258,358,2904 series.

C10(31k ohms)
I'll see if I can find a dual amp somewhere spare to test.

[x-pro]

may also apply TL062 072 082.

[ca7922303]

Check resistance of R22 and R26. Check that resistance from U5 pin1 to pin5 is 1K.
Check that DC volts at U5 pins 4 and 8 are -15V and +15V.

If all that checks out, replace U5.

Replaced U5
Pins 4 & 8(-18/+18vdc)
U5 pin1-5(1k ohms)
R22(1k ohms)
R26(46 ohms)
TP10(0.07)vac
TP12(0.07)vac Unable to increase ac volts at test points with signal generator?

[ca7922303]

Have output thru speaker, but distorted. Headphone output seems normal.

[g1]

Q6 and Q9 are still removed?