[R-390] R-390 non A 12khz jump

[Jacques Fortin]

Not that easy to tap on something inside when the PTO is disassembled.
Unless it can be powered and the output monitored on a frequency counter at the same time...
Good luck with that, anyways.

73, Jacques, VE2JFE in Montreal

-----Message d'origine-----
De : r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net> De la part de Bob Camp
Envoyé : 27 décembre 2024 16:18
À : Kevin Schuchmann <kschuchmann at protonmail.com>
Cc : R390A <r-390 at mailman.qth.net>
Objet : Re: [R-390] R-390 non A 12khz jump

Hi

Even a “tap with a pencil” sort of test might well identify the part that’s the problem. I used to have a plexiglass rod in my tool kit for that sort of stuff. Way safer than “tap with your finger” on tube gear. :)

Bob

> On Dec 27, 2024, at 3:14 PM, Kevin Schuchmann via R-390 <r-390 at mailman.qth.net> wrote:
> 
> 
> Thanks to Tisha and Jacques,
> 
>   It is a model 1 PTO and I have started the disassembly  and will check those capacitors closely.
> 
> Kevin
> 
> 
> 
> On Friday, December 27th, 2024 at 10:32 AM, Tisha Hayes <tisha.hayes at gmail.com> wrote:
> 
>> 
>> 
>> I would suspect a capacitor in the PTO circuitry that is on the verge 
>> of failing.
>> 
>> A can of freeze spray may help you isolate the specific component; 
>> Maybe even tapping on caps/resistors with the tip of an insulated 
>> tool might help identify if there is a cracked component that works differently.
>> 
>> The ballast tube would not be so 'precise' in causing a 12 KHz 
>> offset. It is also a very simple thermonic device with an iron 
>> filament in a hydrogen atmosphere that is just a current regulator.
>> 
>> Ms. Tisha Hayes, AA4HA
>> 
>> "We live in accordance with the flow of the times"
>> -Yoshio Mizuno
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