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

[Les Locklear]

I had a Progressitron PTO in a 1962 Amelco R-390A/URR  that was doing something similar. Upon opening the PTO, I discovered one of those tiny npo caps had a bad solder joint and would intermittently make contact. I cleaned up the solder joint and made it good. It was one of the better PTO's that I had in the rest of the R-390a/URR's and one R-390/URR. This was before I retired and makes that event over 17 years ago.
 
Diddlesticks are great for tapping on microphonic tubes and places where you can obviously detect the result of tapping, etc.
 
Les Locklear
Gulfport, Mississippi
Dx'ing since '57


----- Original Message -----
From: Jacques Fortin <jacques.f at videotron.ca>
To: 'Bob Camp' <kb8tq at n1k.org>, 'Kevin Schuchmann' <kschuchmann at protonmail.com>
Cc: 'R390A' <r-390 at mailman.qth.net>
Sent: 12/27/2024 4:06:04 PM
Subject: Re: [R-390] R-390 non A 12khz jump
________________________________________________________________________________

> 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
>>> ______________________________________________________________
>>> R-390 mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/r-390
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:R-390 at mailman.qth.net
>>> 
>>> This list hosted by: http://www.qsl.net Please help support this 
>>> email list: http://www.qsl.net/donate.html
>> ______________________________________________________________
>> R-390 mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/r-390
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:R-390 at mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net Please help support this email 
>> list: http://www.qsl.net/donate.html
> 
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> 
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html