The Smoked 400

laatsch55 said:
9R--- -.011
6R-----.011
PNPR- -.011

Bias tranny
Collector -14.58
Base -15.2
Emitter -16.7
Click to expand...

Hi Lee
I am having a very hard time reconciling -0.011V on 9R, 6R and PNPR for several reasons. I would believe that on 6R because that is the normal offset voltage for a RevD board that is regulating properly. But having 9R and PNPR being identical is not computing for me. 3 different circuit points with exactly the same reading? That would be OK if it was readings along a common circuit trace but 9R and PNPR are miles apart from a circuit standpoint.
 
Yes , 100 ohm resistorsd in place. And we had good numbers before I put D9,10 back in circuit...D9,10 are now back out on the right channel..
 
Gepetto said:
Hi Lee
I am having a very hard time reconciling -0.011V on 9R, 6R and PNPR for several reasons. I would believe that on 6R because that is the normal offset voltage for a RevD board that is regulating properly. But having 9R and PNPR being identical is not computing for me. 3 different circuit points with exactly the same reading? That would be OK if it was readings along a common circuit trace but 9R and PNPR are miles apart from a circuit standpoint.
Click to expand...

Sir Joe, I shall measure them again. Ground reference --Star Ground---
 
73 volts on the rails

-.013 on 9R, 6R, PNPR....

I had 2 broken wires between the driver board and the backplane on the left channel, 10L, 5L. Bias collector is now +.268, Base -1.402, Emitter -2.054 on the right cxhannel. left is good on 9L, 6L, PNPL...
 
laatsch55 said:
73 volts on the rails

-.013 on 9R, 6R, PNPR....

I had 2 broken wires between the driver board and the backplane on the left channel, 10L, 5L. Bias collector is now +.268, Base -1.402, Emitter -2.054 on the right cxhannel. left is good on 9L, 6L, PNPL...
Click to expand...

Do you have +73V on pin 7R?
What do you measure on Q10R-Base?
Do you have -73V on pin 3R?
 
+.328 both sides, not stable though, the left side of R75R is where i took the base measurement. Numbers head down...
 
Joe, I can move the board around and the bias comes back on 9R, PNPR....I've got some investigating to do here. No rhyme or reason to the movements of the board to the change in voltage..
 
It appears I can bend the right hand corner down and the voltage comes back...still checking stuff..
 
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