Posted by
Don Wilhelm-4 on
Jan 11, 2014; 8:52pm
URL: http://elecraft.85.s1.nabble.com/Alignement-and-Test-part-II-VCO-Test-not-reading-8-to-10-MHZ-range-tp7582755p7582756.html
Mario,
I assume "no voltage" is equal to zero volts, which is a perfectly valid
voltage measurement. I know it is a subtle point, but such clarity is
important for successful troubleshooting.
A zero volts indication at the left end of R30 is an indication that the
VCO/PLL circuits are trying to create more capacity in the varactors
because the frequency is too high.
The first thing to do is check the number of red turns on T5 - it must
be 16.
Then check the value of C72 - it must be 270 pF (marked 271).
Check the soldering of C72, T5, and relays K13, K14 and K15. Re-flow the
solder with a hot iron (750 degF).
Additional checks -- do you have 4 volts at U6 pin 5? If not, you have
a problem with the Thermistor Board (likely a solder bridge). You can
reach the solder side of the Thermistor board by removing the Control
Board and Front Panel.
If those steps do not fix it, ask again and we can offer more
measurements and suggestions.
BTW: If you are posting from Nabble, include some of this post in your
reply text so those of us who are receiving the direct reflector posts
have some reference for what has gone on before. It seems Nabble strips
out the prior post history assuming that everyone uses the Nabble
"forum" - that is a bad assumption. Copy a part of the previous post in
your reply so we have a reference.
73,
Don W3FPR
On 1/11/2014 3:13 PM, VA2EK wrote:
> On K2 serial 7168, I measure in the 12,000 MHz range. If this can be of
> useful info, in the VFO Alignement Test, there is no voltage at R30 and the
> R30 value doesn't change upon L30 position.
>
> Thanks,
>
> Mario -VA2EK.
>
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