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IC 211 PLL Alignment help needed



Hi:

I have been trying to reserect/make operable a much neglected Icom IC 211
that had numerous faults, as well as a PLL/VCO that was 
'fiddled' with by a previous owner. The fiddling resulted in the IC 211
being off frequency and unstable.

I tried to follow the alignment instructions provided by Manfred Haiduk,
DD8KQ, however have run into some peculiarities with the VCO output.

Additionally, I do not have a maintenance manual, so am unable to determine
which trim pot to adjust, in order to align the PLL/VCO.

Can anyone perhaps shed some light on the following:

Which coil in the VCO is L3?

Where are trim pots  R 16, R 18, R 20 and R 64 actually located on the on
the PLL? The four trim pots that I can see on the PLL are grouped into
twos, but how do I identify them?

I find that the VCO is not stable at all! It drifts up and down (a stability
problem?) at least 1 KHz in frequency all the time. Depending upon the
settings of the trim pots, it can drift much more(hundreds of KHz).   Has
anyone else seen this problem? Any suggestions as to what it might be?

When the VCO is to be aligned, Manfred's instructions indicate to monitor
the output of the VCO. There are two outputs from L3 of the VCO. One goes to
the PLL and the other goes elesewhere, which one should be monitored?
 

 Regards


John Pavelich

Senior Security Architect
Entrust Technologies Ltd
Suite 200, 100 Park Royal South
West Vancouver, British Columbia
V7T 1A2

Ph:      (604) 913-6732
Cell:     (604) 889-7545
Fax:     (604) 922-1666
E-mail:  john.pavelich@entrust.com
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Jan. 22-25, 2001  San Diego CA

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