Ken,
My first thought would be that if C31 was too far off, none of the
bands would be within range of pll lock. In my case it was the 30M
oscillator that 'hunted'. To correct, rig #1 (6+ circa 98) made the
trip to TT, and they installed the new TXCO on the chassis, on a
bracket. My second 6+ (circa 99) has the TXCO on the board. I
suspect the early oscillator drifted excessively, hence the
external TXCO. Later models had it on board.
73 bill n4lg
At 08:08 PM 9/22/2007, you wrote:
Adjusting C31, the 20 MHz oscillator trimmer, seems to have fixed
it. I
don't understand why, since even if it were slightly off frequency I
would expect the band select xtal oscillators to be locked to it, and
just as stable as it was. Maybe it was a long way off though and
the PLL
trying to pull them too far. Too bad I didn't look at the freq.
counter
before I tweaked C31.
On my rig C31, the trimmer for the 20 MHz oscillator is on the logic
board. If I had the upgraded TCXO, would the trimmer be on the
TCXO can?
N6KB
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