Boston GT 50

[Perry Babin]

Is R329 within tolerance?

Some amps with similar circuits use 4.7v Zeners.

 

[Hexhclass]

R329 is within tolerance
My probe slip and short the zener.It also took out the 339.
I replace the 339 and the zener(used 5.1v)
Now voltages change:

#339
pin1: 9.08
pin2: .06
pin3: 15.26
pin4: .27
pin5: 9.80
pin6: 6.08
pin7: 10.14
pin8: .06
pin9: 9.78
pin10: 2.52
pin11:.00
pin12: .00
pin13:.20
pin14: 2.51

SG3525
pin13:15.40
All other pins is less than 1v

Q80
E:4.90
B:5.61
C:4.92

I still can not find out why B+v to pin 15 on the sg3525 is missing

 

[Hexhclass]

Both LED on this amp is lit now

 

[Perry Babin]

15+v may be too high. Did you try setting the supply to about 13v?

Did you remember that you cannot connect B+ and remote at the same time?