Garey, Eddy, Paul, Curt and Steve,
Thanks for the quick replies guys. This is a great bunch on this list. I
am convinced that it is the PTO. If I lightly tap on the PTO can with a
pencil tip (and I mean very lightly) it causes the signal to jump
around. Maybe just a cold solder joint. I have a parts radio (T-4XC)
with a PTO in it. I guess I'll haul it out and test it. If it's stable,
I will swap it with the faulty one. Can I then rebuild (shotgun) the bad
PTO with all new parts? or is there special parts in there that I have
to be careful with? I probably have most of the stuff in stock (NPO
caps, metal film resistors etc.). It would be handy to have a nice new
spare because I also have a B-Line. Also, A 5Mhz PTO is a nice thing to
have around, homebrew QRP rigs etc.
I have a HP signal generator, so I think I will try Paul's suggestion on
the Lissajous display. Perhaps I can find the faulty component with some
freeze spray and make this a quick repair. Maybe learn something in the
process (heaven forbid).
I wrote this e-mail in three sittings as real life keeps intervening.
The bottom line is, thanks for all the help, I will let you know how I
proceed and the results thereof.
73,
Bob K6GGO
On 2011-10-26, at 1:16 PM, Steve Wedge wrote:
Removing the PTO - at least with the A's and B's - requires removal
of the front panel. This is a good time to clean it as well as the
fiducial window. Use only dish soap for the window or you'll take
off the red line!
*/
/*
*/Hi Guys,/*
Well, I can not vouch for the "A" & "B" series, but in my T-4X
transmitter /that/extensive a dis-aasembly is most assuredly
*/NOT/*required...
After removing the three tubes immediately behind the PTO can, the can
itself is extricated by first dis-connecting the top grounding spring,
& then lightly squeezing together the "side prongs" that hold the can
in place, one prong at a time (this is by far the /WORSE/part of the
operation, and the most time-consuming).
The can is slipped off the assembly, rearward (where the 3 tubes were).
Next, with a pair of long needle-nose pliers, each brass spacer that
you see at the front of the vertical PTO board is grasped (so the
spacers won't fall & get lost), and a slotted screw driver is used to
unscrew the 4 screws that go through them. The PTO board & coil
assembly is now loose, save for the 3 wires that are attached to the
front vertical board: draw a simple sketch showing where these are
connected so that you'll remember when you re-assemble everything,
then touch each point on the board with a soldering iron to release
each wire...
The entire assembly is then slipped back off of the brass rod with the
ferrite slugs on it.
Absolutely /no need/to remove the front panel, no need for
/anything/that complicated, or involved...
To re-assemble, simply reverse this procedure! Hi Hi
*/~73~ de Eddy VE3CUI - VE3XZ/*
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