[R-390] 3MC issue updated

[2002tii]

>I have cleaned the xtal and it worked when I put it in my 75S-1

The fact that the 3 MHz and 20 MHz bands have the same fault, but no 
other bands do (i.e., the oscillator circuit itself is working), 
pretty much narrows it down to the crystal.  The fact that the 
crystal worked in another radio doesn't really mean anything -- 
apparently, the crystal is south of marginal for a 390 and the 75S1 
oscillator circuit has more gain (in the 390/390A, oscillator gain 
was deliberately kept low-ish to reduce harmonics and, therefore, 
spurious responses).

You could try changing the oscillator tube, but it really sounds like 
you need a new crystal.

Best regards,

Don


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