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

[frledda at att.net]

Hello,

Before finding the PTO guilty, I would make sure that the problem is not
limited to  a group of bands and/or a 1MHz band. 

If limited to frequencies below 8 MHz band, the 17MHz crystal may be faulty.
If limited to a single 1 MHz band, the corresponding crystal may be bad.    

Best, Francesco K5URG

-----Original Message-----
From: r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net> On
Behalf Of Tisha Hayes
Sent: Friday, December 27, 2024 12:33 PM
To: R390A <r-390 at mailman.qth.net>
Subject: [R-390] R-390 non A 12khz jump

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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