Thanks, Don.
Found the intermittent display problem. And, it was a solder problem. I
checked the thermistor and all checks OK there. I'll keep looking ... think
I have ruled out the misplaced or misused component option. I'll just go
through all the RF board installation steps and check each one. All the
other test results are perfect. Got to be something in the synthesizer
circuits I have goofed up. Just gotta find it. Thanks again.
73,
Jim, K4ZMV
----- Original Message -----
From: "Don Wilhelm" <[EMAIL PROTECTED]>
To: "Jim Brassell" <[EMAIL PROTECTED]>; <elecraft@mailman.qth.net>
Sent: Sunday, September 24, 2006 9:34 PM
Subject: RE: [Elecraft] VCO Alignment
Jim,
The most common source of problems with the PLL or VCO is a solder bridge
on
the thermistor board. There are other possible sources, but check there
first. You can often get to the back of the thermistor board by removing
the front panel and the control board.
You intermittent display is most likely an unsoldered connection (or
poorly
soldered) - usually on the front panel itself.
So check the soldering first, then re-check the soldering, and when that
is
done, check the soldering - that is the most common failure and misplaced
components runs in second place. Bad components are way down the list.
73,
Don W3FPR
-----Original Message-----
I am building K2 #5731 and I have run into two problems. The
first, and most serious, is in VCO alignment. When moving L30,
the voltage at the left end of R30 does not change from 8.03vdc.
I have been through the entire range of L30, very carefully, with
no change. I pulled out T5 and rewound it. It is as nearly
perfect as I can get it. When I measure vdc on T5, I see
approximately 0.01vdc on 1 and 2 and 2.65 on 3 and 4. I checked
voltages on U4 and U6 and they are in the range of the table in
the back of the manual. I've checked all the components
installed and the soldering. This is my second K2 and I have
been a lot more careful. I'm stumped. Anybody got any ideas.
The second thing is that parts of the mode indicator on the
display have become intermittent. Any ideas on that?
Thanks.
Jim, K4ZMV
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