Heathkit Service Bulletins - HD-15 (Revised &Complete)

[Joseph W Lutz]

                        January 31, 1975
HD-15                                           Bulletin No:
Phone Patch                                     HD-15-1

                             Service Notes

The major complaint is not enough isolation between transmit and receive
circuits.  This results in cycling between transmit and receive when
attempting VOX operation.  Replacing the hybrid transformer could be
tried, but this usually does not cure the problem.  Sometimes the VOX
gain in the transmitter is adjusted too high.  When the unit is
determined to be operating satisfactorily, try to convince the customer
of the advantage of push-to-talk operation.  "You have control over what
is being said, and you will also prevent both parties from doubling, or
talking at the same time."

The VU meter indicates only signal from the receiver into the patch.
Customers seem to think that the VU meter should indicte when a signal is
being fed from the phone line into the phone patch.  This is not so.  In
the case of the HM-15, a -10 VU level appeared to be giving satisfactory
operation.
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                        January 23, 1978
HD-15                                           Bulletin No:
Phone Patch                                     HD-15-2

                    Phone Patch/Bell System Interface

The HD-15 Phone Patch is not registered with the FCC for use directly
with telephone lines.  The Bell System will require a special line
couple, model QKT, for connection to their lines.
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Thats everything I hold up to 1989 that covers the HD-15 Phone Patch.
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73 de Joe  W7LPF/4  [NNN0KUU]
QWCA - SOWP - NCVA - FISTS - RCC
Gordonsville, Va 22942 [Orange Co]

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