Altec 436C build COMPLETED! with questions

[college101]

Nice, I will have to look around for a similar meter...

 

[college101]

I can see where I made some confusing statements! I went back and re-chekd...but this just led me down another rabbit hole

For example..

At point r6/c3= -8 volts  BUT if I measure Pin 8 directly, it measures 16 millVolts... which Confuses me? The tube is interacting even though its in idle?

Similar problems at R3/C2- The voltage wont sit still..it jumps around 74 volts to 125. I have no idea why? Is it the cap?

Pin 6 on V1 sits at 51 volts... while pin 1 jumps all over the place!?

everything else in the circuit seems right...

 

[MagnetoSound]

What are you referencing your readings to? Is your black lead connected to ground?

Grids should not show any significant voltage at idle. DC from V1 is blocked by the caps. R5/R6/R7 node should be ground, check it is.

At point r6/c3= -8 volts  BUT if I measure Pin 8 directly, it measures 16 millVolts...

Pin 8 is cathode, btw. Did you mean pin 7?

 

[college101]

Thanks for you help Magneto-

Yes ...Black is connected to my chassis ground...Its has to be to take voltage readings...

I meant Pin 7- Yes

one side of R5 and R6 is to ground because its a voltage divider...I was referencing the the capacitor/resistor side where signal will be passing...

Ahhhh...brain melt- Light bulb came back on...Forgot to switch back to AC for those measurements..

-8 volts must be wrong  then since I was measuring Dc at those points..which is why the voltage was jumping around....

 

[college101]

Good news! The new uA meter showed up. Connected it, and presto- works great...

I want to make sure that the needle should be moving when I adjust the threshold and release controls?

I know these controls are normally set at specific value and then kept there...

SO-Should I be setting the controls and then adjusting the meter resistor value to sit the needle back to zero on the left hand side of the new dB meter?