HW-16 pot is the problem.

[Curtis D. Levin]

The potentiometer is definitely the problem, or the
cause of the problem. When the receiver wouldn't tune
in any signals, I used a shorting bar across the top
of the pot, so I could use the rig to receive. It worked
fine in RCV mode that way. And it would transmit. I had
a qso into Cuba, we exchanged calls, before the latter
station faded into QSB.

I went down to Radio Shack to get another pot for the RF
gain. Not thinking, I bought a 25 ohm wire wound, since
that seemed to be closer than the 1000 ohm linear they had.
I should have gotten the 1000 ohm, since it would've been
better to use a bigger resistance than a smaller one. When
I installed the pot, aand tried to transmit, is when the
problem developed. So I went ahead and installed the old
pot to see if that fixed the problem. Well, it still didn't
receive, and so I shorted out the two contacts again, and that's
where I was.

Well, while playing around with the transmitter, I noticed the
little light in the back of the unit that signals the transmitter
keydown. I don't know what other purpose it serves, but when the
sidetone, which comes thru the speaker is on, the little light by
the rear of the unit illumens, and the tube switches. With the
cover off it's easily seen. Now, back before I did any of this,
I complained aboyut a hum from the VFO in OPR. Well, while
troubleshooting, I removed the shorting bar from the pot, and
put the transmitter into the OPR position. That's when I saw it.
The little light was coming on, and the tube was switching !
That was the cause of the hum. It doesn't do it with the shorting
bar across the pot, but when it's removed, there it is.

Now, the big question. Does the pot have anything to do with the
tuning of the transmitter ? Is it supposed to be tied in with
the transmitter ? Somewhere along the circuit. I imagine there's
a switching unit for tx/rx, and the pot is probably tied into
the circuit there. Maybe, and I'm guessing, it has something to
do with the sidetone generator. Maybe it doesn't, and there's a
short in the rig elsewhere, or my shorting the pot, or the pot
already being damaged, has caused something else in the transmitter
to fail. I also do not know if the receiver is supposed to deflect
the s-meter, but it doesn't. Even when the unit is getting such strong
signals that it overdrives the speaker. Well, that's where I'm at
now, as before, any and all suggestions are welcome. 73.

 _______________________________________________________
| Curtis D. Levin   | Team Os/2  | cdlevin at dialisdn.com |
| kd4zkw.ampr.org   [44.98.2.22] |   kd4zkw at amsat.org   |
| *Member of HTML Writers Guild* | * * Linux 2.0.33 * * |
|    Webpage  http://www.dialisdn.net/user/cdlevin/     |
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

--- --- --- --- --- --- --- --- --- --- --- --- --- --
To subscribe: listserv at listserv.tempe.gov
and in body: subscribe HEATH yourfirstname yourlastname
To unsubscribe:  listserv at listserv.tempe.gov
and in body: signoff HEATH
Archives for HEATH: http://www.tempe.gov/archives
--- --- --- --- --- --- --- --- --- --- --- --- --- --