My Omni VI is dead, and it seems like it is because the band selecting
crystal oscillator is not generating a signal.
Voltmeter readings indicate that the board is getting the correct DC
supplies , the +REG and +13.5v as well as the appropriate band select
control voltages on connectors 82 and 83. Still I cannot detect a strong
signal at the XTAL oscillator frequency for any band selected. This board
is sort of hard to get to, and I would like to troubleshoot it on the bench
and hopefully confirm it is working before I put it back in the radio.
Since the fault is in the crystal oscillator, I think if I get that working
I'll have it fixed. I don't think I need to supply the 5.0 to 5.5 MHz input
to troubleshoot the crystal oscillator. I think if I give it DC supply
voltages and band select voltage I ought to be able to get it to generate a
signal when on the test bench. With nothing going to connector 84 the
frequency will not be phase locked or precisely controlled but there should
still be a strong oscillation very near the correct frequency for whichever
band I connect the band select voltage to connector 82 or 83 for.
I would like to hear from anyone who has tried this. Do I need to put a DC
voltage on connector 84 to get it to work at all? Or should it oscillate
with nothing connected to 84, and just be sort of free running at the
crystal frequency with no correction voltage?
Thanks, Ken N6KB
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