[Drake] C-Line Carrier Oscillator Problem

[Paul Blumhardt]

Hi All

My First Post to this mailing list. I hope someone can point me in the right
direction with a problem.

This is not my first C-Line, but this is the first time I've encountered
this particular problem.

R4C S/N 19XXX  T4XC 22XXX

Both piece are in VERY nice shape and work fine except for one problem.

Symptom: When CXR OSC cable is plugged into the R4C, with the T4XC set to
SSB Mode, the audio sounds sort of raspy - ike two signals are beating. This
occurs with the R4C set to SSB or CW.

When the CXR OSC cable is unplugged from the R4C, things sound nice and
clean.

This problem occurs whether Transceive (either PTO driving) or Seperate.

I did confirm that the 5645 oscillator freq's are correct on the R4C and
T4XC.

Zero beating the T4XC with the Spot switch doesn't sound right either (with
the cable plugged in).

I know that the Carrier Oscillator is used with the C-Line to insure proper
transcieve on SSB (Drake doesn't do this with early 4-Line sets). This is
accomplished via a phase-lock circuit in the R4C.

So, two questions:

1) How do I confirm if this problem is caused by a T4XC problem or a problem
with the R4C?

2) If it is a phase lock circuit problem with the R4C, does anyone have any
hints to pass on (like you've seen this before). Normal loop troubleshooting
methodology is to break the loop, which is something of a pain with this
circuit.

Thanks and VY 73

Paul K5RT