[Johnson] Ranger I problem

[William Henneberry]

Jim Brannigan wrote:
> More on my adventures with the Ranger.....
>
> I isolated the "talking" to the HV choke, this happens only on AM, not 
> CW.
> Connecting a scope to HV power supply capacitor I get lots of audio on 
> the HV line.
> The RF was disabled, so this is audio...
>
> any ideas?
>
> Thanks,
> Jim
>
>
>>
>> My Ranger was completely refurbed and has been working properly.
>>
>> I put it on the bench to reset the bias and keyer settings, while it 
>> was on
>> the bench I finished the PTT wiring (ala Phil Salas and WA1HLR).
>>
>>
>> While testing it, I noticed that one 6L6 metal modulator tube was 
>> running
>> considerably hotter than the other (laser thermometer)  Substituting 
>> glass
>> 6L6's showed a slight glow on the plates of the tube in the same 
>> position.
>>
>> Then, in AM,  the Ranger started to "talk" to me and I can't quite 
>> isolate
>> the source.
>>
>> Resistance and voltage checks are OK.  Before I start to take it all 
>> apart,
>> any ideas??????
>>
>> Tnx in advance,
>>
>> Jim
>
>
Bill KN2X replies:  As memory serves, the final plates get B+ via that 
choke, and, in series with the choke is a bypass capacitor to ground.
Those chokes rarely give trouble, but shorted turns are a possibility.  
I would immediately suspect the capacitor.
The choke and capacitor should prevent RF and audio from entering the 
power supply.  Since this happens only in AM and not in CW:  either 
component is suspect.