Loren -
It's highly unlikely that BOTH PTOs would develop the "jitters" at the
same time, so the problem is probably elsewhere. Does this occur on ALL
bands, in particular both 80M and 40M for example?
IF it appears on BOTH 80M and 40M, then my next suspect would be the
contacts of relay K2. Does it appear on BOTH SSB and CW, or one or the
other?
V1, the Band Oscillator tube, would be the next suspect, IF the problem
appears on 40M, but NOT on 80M or 20M.
Lastly, how are you determining the instability? If you're listening to
the Calibrator, confirm that it's NOT the Calibrator that is jittery!
Let us know!!
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
Loren McCullough wrote:
What factors could contribute to frequency instability EXTERNAL to the
PTO?
My TR-4C has just developed a "jittery" frequency, jumping back and
forth around center freq by as much as 50Hz. I know someone (if not
many) will refer me to the excellent articles on PTO rebuilds, but
before someone does, let me say that I have rebuilt my internal PTO
last year and it has been working flawlessly since then. I believe
this is external to the PTO because I am seeing the same instability
on both the internal PTO (rebuilt last year as stated previously) and
also on the RV-4C PTO (factory original, but has always been stable,
other than a heat induced drift issue mentioned in another thread).
Is this a Oscillator tube going bad, or some other component in the
freq. chain?
Thanks,
Loren - WA3WZR
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