[Johnson] Ranger keyer

[John Lawson]

On Fri, 6 Jan 2006, Chuck Hurley wrote:

> The keyer circuit will not adjust at all on my Ranger 1.
>
> Adjusting R39 does nothing.  Bias voltages are correct.
> If I short C89 (.047) to ground the unit will key.  Plate voltage @ pin 6 of the 12AU7 is 350 volts
>
> Adjusting R39 through full range causes pin 2 of the 12AU7 to go from 
> -28.7 volts to -66.1 volts.  Pin 7 of the 12AU7 goes from -59.7 to -59.9 
> (basically doesn't change)  It seems to me that the voltage at pin 7 
> would have to approach zero to fire the keyer.


   Some (dumb) questions:

  Whats the First Plate (Pin 1) doing?

  Does the transmitter otherwise operate - the keyer fault is not 
preventing the VFO and/or Multiplier from working?

   Check C20 and C89? if these are shorted or very leaky it might bear on 
this.

   Obviously you've checked R38, R40, and R41.  How's R5?  Is there 
regulated voltage from V2 on the Other Plate (Pin 6?)  (R3 is in series)

   Good ground from SW4A Pin 8 to Pin 7 (in the right mode)?  7 is attached 
to ground, BTW.

  Really dumb - is the 12AU7 (V15) actually lit?


  Last question: Do you despise electronics yet?


Cheers

John   KB6SCO