[Elecraft] VCO Alignment Troubles

[W3FPR - Don Wilhelm]

Tim,

Check and re-check the capacitor values.  From the bands that seem to me to
have strange voltage readings, C73 (should be 47pf) and C74 (should be 20
pf) are the most likely culprits.
Other things to check: be certain the menu parameter for D19 is OFF - check
the relays K13, K14 and K15, set the K2 for the band to be checked and
compare the set/reset condition of each relay by checking continuity from
pin to pin.  The chart on the manual page just before the schematics shows
which relays are set for each band and the schematic shows all relays in the
reset position.  The relay pin numbering is similar to that of an IC - you
can locate pin 1 by finding the round solder pad on the board.

73,
Don W3FPR

> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net]On Behalf Of Tim Cailloux
> Sent: Saturday, February 26, 2005 11:20 AM
> To: Elecraft E-mail List
> Subject: [Elecraft] VCO Alignment Troubles
>
>
> Hello all (again).  I'm attempting to align the VCO and am having
> trouble making it lock on all bands or get to the right voltage range.
>  I've verified all components on the board and touched up the solder
> on the pertinent components and relays (and verified all
> paths/continuity), but nothing changed.  Here are the voltage values I
> get when attempting to set L30:
>
>      Low     High
> 80M  1.937V  6.000V
> 40M  8.000V  8.000V
> 30M  0.597V  0.710V
> 20M  0.589V  1.148V
> 17M  3.054V  3.250V
> 15M  1.962V  2.944V
> 12M  1.131V  1.251V
> 10M  2.336V  4.060V
>
> No setting of L30 will cause 40M to lock.  I also hooked up the
> frequency counter to TP3 per a suggestion previously on the list and
> it measured 8.something MHz on 40 (which doesn't seem to be right.  I
> adjusted the spacing on the turns of T5, either pushing them apart or
> moving them closer.  I was able to bring the lower 20M voltage up to
> 1.5V, but then the VFO wouldn't lock on 80.
>
> Thanks in advance for any help you can provide.  (And thanks to Don
> for correctly surmising that my previous problem was due to a
> thermistor board issue.)
>
> tim
> --
> Tim Cailloux
> W4EGT
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