What I Learned about Heathkit LMO's
I checked the BAMA note, and every place else I could find, without
result. BAMA has a schematic of the solid state (a la 303 and 102 rigs)
LMO, but no hints such as I am seeking. Neither my '301 rcvr nor '102
vxcr uses the same part number LMO, but I guess I can look inside to
see for a comparison of the variable cap position.. So far as being set
somewhere in mid-value of the variable cap, that may be true. I'll lock
down the tuning bits and give it (5) rotations- that will tell me if
STOP to STOP on the dial is equal to full rotation of the cap. Thanks
for your suggestions.
Chuck Harris wrote:
sargent wrote:
MISTAKE! I forgot to note
whether the variable capacitor driven by all this was at min
capacitance or max capitance when the shaft was in the full
counter-clockwise position.
I believe you are going to find the capacitor was at neither position,
but rather somewhere in the middle. They were looking for best linearity,
and that is never found near the ends of travel.
So what is you best guess? Should I try MIN
or MAX capacitance for the fully counter-clockwise rotation(lowest
frequency)? I can change it later if wrong, but I would like to save
all the disassembly and reassembly if I can.
What I would do, is power up the LMO, and adjust the capacitor to
the highest frequency, and then setup the stack for the correct
rotation direction. (which I don't recall). The LMO tunes 5.0-5.5 MHz,
though.
I went looking for LMO instructions, and found them first try using
google:
Heathkit LMO repair
The instructions are on the BAMA site.
-Chuck Harris
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