Richard -
Yes, one wonders...... :-) This type of 'dithering' is known in PTOs, but although much less
common, a poor crystal oscillator such as the BAND or 2nd MIXER oscillators 'could' present the same
way.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>
Richard Knoppow wrote:
----- Original Message ----- From: "Eddy Swynar" <[email protected]>
To: "Curt Nixon" <[email protected]>
Cc: <[email protected]>
Sent: Friday, July 29, 2011 9:54 AM
Subject: Re: [Drakelist] R-4A PTO: It wasn't the transistors (entirely)
I have so far not had this problem any of my drake gear so I don't have direct experience
trouble shooting it. Since so much of the PTO has been investigated without success I wonder if
the problem could be external to the PTO. Either another oscillator or something after the PTO
that is affecting it. I have no specific suggestions other than monitoring the PTO output with a
receiver to make sure that is what is varying. Probably so but its worth being sure. Also, if it
seems to be heat sensitive it may be possible to use a low power soldering iron to selectively
heat compenents. I find a heat gun is too diffuse, it heats everything. Freeze mist is evidently
hard to find now (I think it was Freon) but canned air works if the can is held upside down.
Have you examined the coil to see if there is a loose turn? I know this is
grasping at straws.
Everything else I can think of has already been tried. It is so frustrating to trouble shoot
something where all the parts are good but the thing doesn't work.
--
Richard Knoppow
Los Angeles
WB6KBL
[email protected]
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