Quote:
Originally Posted by dtvmcdonald
Try sweeping the combination of L42 and the 270 pF in parallel with it.
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That's what I meant by 'tank' - both coil and cap in parallel.
Quote:
You could try disconnecting the 270 pF
capacitor and connecting in a standard 365 pF variable, and
varying that to see if you can get oscillation.
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Ha. I was going to suggest that very thing, assuming he's got an old AM radio tuning condenser knocking around somewhere.
Kinda wonder if the coil could have some shorted turns in it, considering the uber-fine gauge wire it's wound with.
Here's another idea that's sort of a 'Hail Mary' gambit..
See if the osc. can be made to free-run on just the crystal. Disconnect the LC tank completely and replace it with a resistor (leaving feedback cap C209 in place). Try several values of resistor, from maybe 47 ohms thru 560 ohms or more.
If it'll start and run, that would pretty well confirm the fault lies with the LC combo.