19-08-2018, 06:29 PM
Ooh! What a nasty combination of NPN and PNP transistors!
It's doing my head in going back and forth from the circuit to the text!
The VDR is part of the bias potential divider for both types, which is distinctly odd.
Your voltages bear no relationship to the few shown on the circuit. Have you checked the voltage on the -7V line at point A WRT to ground?
There is definitely something very wrong there as the emitter of T304 is connected directly to ground (positive) yet you measure the voltage WRT the negative line as 0V!
Obviously, if there was a short across the supply like that, all the voltages would be zero!
Have you correctly identified Point A, Mike?
Perhaps, as a sanity check it would be useful to have a fresh set of readings WRT to ground.
If the VDR is o/c it will definitely screw up the bias supplies for all of these stages - some data on the VDR would be useful.
It's doing my head in going back and forth from the circuit to the text!
The VDR is part of the bias potential divider for both types, which is distinctly odd.
Your voltages bear no relationship to the few shown on the circuit. Have you checked the voltage on the -7V line at point A WRT to ground?
There is definitely something very wrong there as the emitter of T304 is connected directly to ground (positive) yet you measure the voltage WRT the negative line as 0V!
Obviously, if there was a short across the supply like that, all the voltages would be zero!
Have you correctly identified Point A, Mike?
Perhaps, as a sanity check it would be useful to have a fresh set of readings WRT to ground.
If the VDR is o/c it will definitely screw up the bias supplies for all of these stages - some data on the VDR would be useful.
