Expected transistor voltages?

[OurReligion]

I've just finished building my 1st N72, powered it up and it won't pass a signal. I notice that the transistor names have changed ( Q3 = Q6 now???) from what is described here on your website under 'assembly'.

Is there some updated info somewhere indicating (for instance) expected transistor 'no-signal' voltage values for the updated circuit?

What course of troubleshooting should I embark upon? Trace a signal from input, point by point, through the circuit until I find out where it's disappearing?

Thanks for the help for a newbie here.

Ric

[tpryan]

What are the voltages at the power connector? Using R39, are you able to adjust the collector voltage of Q6 (the big power transistor) to 21.5V or so? (The collector is the transistor case.) Have you jumpered CONN3 pin 1 to CONN3 pin 3? Check this stuff before you worry about the other transistor voltages.

[OurReligion]

I WAS able to adjust R39 to set Q6 coll. voltage to 21.4V

Ahhhh...I have NOT jumpered pin1 & pin3 of conn3. Yes, I see on the schematic where that would be important. Duh. Going to do that now.

Thanks, Tim.

[tele_player]

CONN3 got me, too. I had the scope and signal generator hooked up, and was tracing signal, and... aha!

[OurReligion]

Success! It works.......now to do the bias adjust.

Thanks,

Ric