On all those switches.
Cleas with good contact cleaner (not too much)
Then apply DeOxit Gold..AND check the mechanical alignment to be sure
the rotor is centered on the tabs!
Problems gone...
Oh, one other thing, put on yout magifyers...lots of light and check
that as you turn the rotor to each tab, the contact moves a
little.....this is critical for long term function.
73,
Lee , KC9CDT
-----Original Message-----
From: Eddy Swynar <[email protected]>
To: k4oah <[email protected]>
Cc: drakelist <[email protected]>
Sent: Fri, Aug 26, 2011 1:18 pm
Subject: Re: [Drakelist] T-4X PTO Stability
Hi Garey,
I was able to replicate the raspy warble that I've come to know in my
PTO signal only TOO well here, by slightly turning the mode switch away
from what I consider to be its "normal" detente. By turning it ever so
slightly counter-clockwise, that induced shift would "hold"---by
turning the switch clockwise, it would hold only for the duration of
the VOX hold setting...
Interesting, huh...?
Maybe that's what's plaguing poor Steve there with his PTO, i.e. the
PTO itself may well be good, but its environment isn't...
Just a thought...
In any event, I've just loaded the Drake Twins into the car, & will
fire 'em up at the cottage shortly. I'm gonna monitor my signal
directly from the R-4, too, rather than use the keying monitor.
Stay tuned...! (pun intended, Hi).
~73~! de Eddy VE3CUI - VE3XZ
*************************************************************************
************************************************
On 2011-08-26, at 1:08 PM, Garey Barrell wrote:
Eddy -
The Carrier Oscillator is shifted in frequency by about 900 Hz in the
CW position. This is accomplished by putting a capacitor (C177) in
series with the ground end of the CO crystal. The MODE switch shorts
this capacitor to ground in SSB and TUNE position. So certainly a poor
switch contact could easily shift the frequency anywhere from 0 to 900
Hz or so depending upon just how well it shorts that cap.
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>
Eddy Swynar wrote:
Hi Again All,
Well, to-day I could have SWORN that some demon had taken possession of
the PTO in my T-4X transmitter,& that it was sent to this earth with
the express purpose of taunting me...!
I mentioned before that last week I re-soldered a visibly bad
connection of the 33-pfd. temperature compensating capacitor to the
board of my PTO, and that---so far!---it appeared to be the proverbial
"silver bullet" in fixing the "warbling". Well, this morning---at the
very moment that I was seriously considering taking the "4-Line" on a
road trip to the cottage to test the PTO "in the field"---the frequency
suddenly jumped a coupla KHz, and was raspy-sounding...!
Oh no, here we go again! ("Why do the gods taunt me so...?!").
Turns out---I think!---that I was monitoring the T-4X with the function
switch in the "Tune" position. By wiggling that switch
ever-so-slightly, I could make the frequency jump a prescribed amount
of KHz----exactly the amount that I get when switching the mode switch
to Phone.
I wonder if a dirty mode switch may have contributed to my initial
confusion in this whole matter...?
The testing continues...
~73~ de Eddy VE3CUI - VE3XZ
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