[Johnson] Ranger I problem

[Jim Brannigan]

Thanks for all the replies....
I checked the resistance of the driver and modulation transformer windings, 
it is very close to the measurements I took two years ago.
It might be that the windings break down only under Hi-voltage.

Next step is to have someone else talk into the mic and use a wooden stick 
to isolate the "talk back" problem.

Jim


> The resistance on each side of center on the primary won't necessarily be
> the same. Its been awhile since I checked a good transformer so I can't
> remember the difference but it can be in the order of 10% or so difference
> from one side to the other. This is due to the different lengths of wire 
> on
> each side of the primary. It takes more wire as the core gets bigger.
>
> Maybe they will tell you in the manual what the difference should be.
>
> 73
> Gary  K4FMX
>
>> -----Original Message-----
>> From: johnson-bounces at mailman.qth.net [mailto:johnson-
>> bounces at mailman.qth.net] On Behalf Of Craig C. Heaton
>> Sent: Monday, August 21, 2006 6:30 PM
>> To: Jim Brannigan; johnson at mailman.qth.net
>> Subject: RE: [Johnson] Ranger I problem
>>
>> Jim,
>>
>> Take a look in the manual and see if the dc resistance is listed for the
>> modulation transformer. On the primary side each side to center should be
>> the same, hope the manual gives values for both primary and secondary.
>>
>> I had talkback problems in a Johnson "500", Peter Dahl to the rescue. Had
>> to
>> buy a new mod tranny, the old one didn't have the same resistance on the
>> primary (each side to center) and the secondary was out of spec (internal
>> short).
>>
>> 73's
>> wd8kdg
>> Craig
>>
>> -----Original Message-----
>> From: johnson-bounces at mailman.qth.net
>> [mailto:johnson-bounces at mailman.qth.net]On Behalf Of Jim Brannigan
>> Sent: Monday, August 21, 2006 3:00 PM
>> To: johnson at mailman.qth.net
>> Subject: [Johnson] Ranger I problem
>>
>>
>> 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