The Paragons had chronic PLL problems, mainly due to poor solder joints
on the "major loop" and "minor loop" boards. The usual fix is to
resolder all connections on both boards. However, if the problem seems
to be temperature related, there is an easier tweak to try first.
On the major loop board on some Paragons, there is a small pot
mounted at U3. You will find that turning this pot slightly in either
direction will cause the PLL to go in and out of lock. Set the pot
to the middle of the lock range. I found the optimum setting to be
with 3.2 V on the pot wiper.
If the problem persists, you may have a cold solder joint on the
highest range (22- 30 MHz) VCO on the major loop board. This is
the VCO located in the shield can on the far left side of the
major loop board, with the front panel of the rig facing you.
(There are 4 VCO's in shield cans on this board.
To check the alignment of the PLL, connect a dc meter to the test
point at the junction of Q1-C and Q3-C. The voltage should run
from about 2.8 V at 22 MHz to 7.7 V at 30 MHz.
The PLL boards are located on the top of the chassis, under the
shield cover where the FM option is mounted. The major loop is
toward the front and the minor loop is toward the rear.
I hope this info helps; I'm sure that you will fix the problem.
73, bob WB2VUF
Charlie Johnson wrote:
> Hi all you Ten Tec gurus -----
> I have a Paragon I, s/n 218, that I bought new in '89 I believe, that has
> developed a slight problem. When the rig is cold, the message 'PLL OUT OF
> LOCK' will flash once a second or so, only if the rig is tuned to a
> frequency above about 22 Mhz. While the rig is still cold I can tune below
> 22 Mhz, somewhere around 21.5 Mhz and the PLL will lock and the rig will
> work fine. On very rare occasions, it will occur no matter what frequency
> the rig is tuned to. Generally if the rig is tuned to say 7.1 Mhz, I never
> see the problem at all. The problem goes away after 10 to 15 minutes of use
> (after it warms up good) and the rig will work normally. I suspect that a
> good alignment would solve the problem, but I don't know if I want to try to
> tackle that. At present, I don't have a service manual on the rig, nor, I
> imagine, do I have all the required test equipment. I'm hoping someone else
> has had a similar experience, and can point me to a particular circuit or
> component to tweak. The only other option is to ship it back to TT, I guess,
> but that would put me off the air :-(.
> Any ideas, gurus?
> Thanks and 73, Charlie, K4ZRJ
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