[Johnson] Invader 200 Help

[David C. Hallam]

Ed,

I have correspondence from Johnson dated 2/20/62 with a slightly 
modified procedure for adjusting T2.

  * Mode switch to CW
  * RF level to maximum clockwise
  * Connect VTVM probe to pin 9 of V3
  * Short out T5 trimmer with an alligator clip
  * Adjust the slug of L3 so that the top of the threaded rod is 9/16"
    above the metal cap of the coil (not the metal ears)
  * Bottom core of T2 should be at bottom limit of its travel
  * Run top core pf T2 through the first peak as evidenced on the
    voltmeter and adjust for peak reading at second peak reached
  * Adjust bottom core to second peak reached
  * Readjust top and bottom cores if necessary to obtain maximum reading
  * A minimum of 1 volt should be obtained at pin 9 of V3 with full RF
    level control (if balanced modulator had been balanced previously,
    it will have to be unbalanced)
  * Remove voltmeter probe
  * Remove alligator clip from T5
  * Set trimmer to approximately 35 to 40 degrees from maximum capacity


I have had no trouble getting 1 volt of RF using this procedure.  
Currently I am having a problem with mine, getting all kinds of spurs 
when I try to zero beat the receiver frequency.  It's going on the bench 
next week to see what's going on.

David
KW4DH

On 9/17/2011 2:31 PM, ewirtz wrote:
> Hi,
>
> I'm working on a sick Invader 200. First of all I need to find a good
> T2, the 9MHz Amplifier Tuning transformer, or a suitable replacement.
> Second if any of you guys know where I can find typical RF voltage
> measurement data for the 9 MHz amp, 1st mixer etc. I'm sure someone out
> there has suffered through the same things I am with this worth brute.
> Any help or advice will be gratefully appreciated. Please don't tell me
> to trash it instead. Hi!!
>
> 73,
>
> Ed, KØBKA
>
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