Re: {Collins} 75A3 15 M update.

On Nov 3, 2014, at 12:54 AM, Dan Presley <n7cqr@xxxxxxxx> wrote:

> ... I think I've determined that the 15 M oscillator isn't in fact running.

> ...Anyone have a spare 23.3 Mhz xtal with the correct pin spacing for this rig lying around?

I think that they are normal HC-6 style crystals.  Put the suspect crystal into the socket for another band and see if it oscillates.  Or put one of the other crystals into that band socket and see it it oscillates.  This might now work since the coil and cap in the plate circuit is tuned to the crystal frequency.

You should suspect the silver mica cap associated with that band crystal.  Also, check that there is plate voltage on pin 1 of the tube to see if the coil is open.


Roy Morgan
K1LKY Since 1958

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