[Johnson] Ranger I problem, Solved!!!

[Jim Brannigan]

To all,
The replacement capacitors arrived today and were installed.
I am happy to report that the problem is solved!!!!

I don't yet know if this also took care of the modulator imbalance, (I'm 
making voltage and scope checks under the
chassis), but all signals look clean.

Thanks again,
Jim

> Cal, etal....
> Preliminary autopsy:
> My Ranger choke input HV supply was modified with two 330MF 450VDC filter 
> capacitors (in series with appropriate dropping resistors)
> This was for better power supply regulation.
>
> The plastic insulation on one of the capacitors wore away and the case was 
> intermittently shorting to ground.
> Naturally, this was the capacitor on the top of the string, so 700VDC was 
> impressed across a 450VDC capacitor. zzzaaaaap!
>
> I don't know if this is the complete solution, but I can't proceed until 
> it is replaced.
>
> Two capacitors were ordered today.
>
> Thanks for your input....more to come...
>
> Jim
>
>
>> Sounds like a decoupling problem. I don't know how to
>> pin this down but check your bypass caps and
>> decoupling caps. I have had a disc ceramic fail in a
>> Valiant II. A good hint is the appearance of those
>> caps that like they have a fried/bubbly/burnt look.
>> FWIW. Cal.
>>
>> --- Jim Brannigan <jbrannig at optonline.net> 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