[NJARC] Radio Debugging PS

[Al Klase]

See below.

Scott Roberts wrote:
> Visit our web site - See http://www.njarc.org
> _______________________________________________
> John(and Al)
>
> I made the changes, and it -did- pull the numbers a bit closer to
> "factory ideal", 
Get that "ideal" stuff out of your head.  It will make you crazy.  If a 
plate is suppose to be 270 volts and your meter says 6, there's a 
problem.  (Like an open plate load.)  If a screen grid is suppose to be 
100 volts, and the meter says 50, the screen resistor is most likely 
cooked high. ETC ETC  - READ THE SCHEMATIC!

> although my 5 pins are still high- actually got
> higher with the changes... 
READ THE SCHEMATIC!  Pins 5 and 8. cathode and supressor grid, are wired 
together on all three 6K7's.  In spite of this the stupid voltage chart 
claims different voltages!  Impossible.  Use the pin-8 values.  Charts 
like this are just a guide.  HOW DOES THE RADIO WORK?
> And the beat osc. 6J7, is showing 8.75
> on 3&4(should be 150, each) and 165 on pin 6(should be 350).
> Also, I have a -32 on pin 5 of either 67 Mixer or 6J5G Osc.(I
> have to recheck- it is showing on one in the first check, the
> other on the second, so I may have written in the wrong box...)
>   
Pins 3 and 4, the screen grid and plate, are low because the BFO is not 
turned on, SW 2.  READ THE SCHEMATIC!  tell us which tube elements are 
involved, so we don't have to look them up.  If the switch is on, turn 
the set off and ohm the circuit and find out why there's no voltage.  
READ THE SCHEMATIC!

HOW DOES THE RADIO WORK?  do you get a beat not when tuned to a station 
and you turn on the BFO?
> I am going to retest the tubes before I proceed further. 
> Still trying to figure why the Beat Osc numbers are so low. They
> are the same with BFO on or off, and with RF at high.
>
> Oh- and I think that "motorboating like noise" came from the
> meter! I noticed it coming form that area when I switched the RF
> gain to full. I think it may have been out of adjustment: the
> needle went full left. So I turned the adjuster just a little to
> bring it back up to zero
>
> As to VTVMs, I have several- now I have to remember which one
> WORKS! 
>   
I'd continue using the DVM.  It should be more reliable.

-- 
Al Klase - N3FRQ 
Flemington, NJ 
http://www.skywaves.ar88.net/