Bob -
The RTTY shift is the only difference between USB and LSB switch
positions aside from the filter switching. In LSB only R16 is grounded,
enabling the RTTY shift circuit controlled via J2 and Q4, CR2 and CR3.
If J2 is shorted, the CO frequency is shifted approximately 500 Hz (470
Hz!) to alter the LSB audio frequency response and allow the old
standard high tone of 2975 Hz to pass through. A short on J2, or the
associated wiring.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs
www.k4oah.com
Robert Fish wrote:
Hi Guys,
I have a T-4XC that I thought I repaired. I replaced the crystal on
the carrier oscillator board. I was then able to bring the oscillator on
frequency with C-6. I put the transmitter through some testing before
I put the covers back on and I noticed that the carrier oscillator
changes
frequency when I turn the sideband switch. Upper sideband reads
properly 5.645 MHZ and lower sideband reads 5.64453 MHZ. I would not
have noticed this if I hadn't still had my freq counter plugged into
the carrier osillator jack while switching sidebands.
Any ideas what is going on here?
Thanks,
Bob K6GGO
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