HEATHKIT SERVICE BULLETINS - HW-16/22/32/32A

[Joseph W Lutz]

                        SEPTEMBER 9, 1971
HW-16                                           BULLETIN NO:
NOVICE TRANSMITTER                              HW-16-2

                        RESISTOR FAILURE

DUE TO REPEAT FAILURE OF A RESISTOR IN THE FIELD, THE FOLLOWING CHANGE
SHOULD BE MADE IN ALL UNITS BEING SERVICED:

CHANGE:  R21 22K 1 WATT TO 2 WATT [PN 1-11-2].
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                        JUNE 15, 1967
HW-22                                           BULLETIN NO:
40M SSB TRANSCEIVER                             HW-22-1D

                              VFO DRIFT

SEE BULLETIN NO: HW-12-1D DATED JUNE 15, 1967
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                        APRIL 15, 1968
HW-22                                           BULLETIN NO:
40M SSB TRANSCEIVER                             HW-22-2D

                         IF FEEDBACK IN RECEIVE MODE

SEE BULLETIN NO: HW-12-2D DATED APRIL 15, 1968
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                        JUNE 15, 1967
HW-32                                           BULLETIN NO:
20M SSB TRANSCEIVER                             HW-32-1D

                              VFO DRIFT

SEE BULLETIN NO: HW-12-1D DATED JUNE 15, 1967
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                        APRIL 15, 1968
HW-32                                           BULLETIN NO:
20M SSB TRANSCEIVER                             HW-32-2D

                   IF FEEDBACK IN RECEIVE MODE

SEE BULLETIN NO: HW-12-2D DATED APRIL 15, 1968
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                        MAY 8, 1979
HW-32A                                          BULLETIN NO:
20M SSB TRANSCEIVER                             HW-32-1

                RELAY CHATTER IN THE VOX MODE

WHILE THE RELAY IS CHATTERING, MONITOR THE JUNCTION OF R200 AND C204 WITH
AN OSCILLOSCOPE.  IF YOU SEE A NEGATIVE 12-VOLT PULSE, 4 MILLISECONDS
WIDE, REMOVE C203.

C203 IS INTENDED TO "SPEED-UP" THE CUT-OFF VOLTAGE TO V1B WHEN GOING TO
THE RECEIVE MODE.  HOWEVER, IT IS ALSO THE CAUSE OF THE RELAY CHATTER.
WHEN IN THER TRANSMIT MODE, V10 IS CUT OFF AND V2B IS SATURATED, SO THAT
THE RELAY IS ENERGIZED.  IF NO ONE IS SPEAKING INTO THE MICROPHONE, V10
WILL SATURATE AND V2B WILL CUT OFF.  THIS DISCONNECTS PIN 1 OF THE RELAY
FROM R203 AND SENDS A NEGATIVE PULSE THROUGH C203/R200, THE MIC GAIN
CONTROL, C14 AND ON TO THE GRID OF V10.  V10 CUTS OFF, CAUSING V2B TO
AGAIN TURN ON AND RE-ENERGIZE THE RELAY.  AFTER A SHORT PERIOD, V10 WILL
AGAIN SATURATE, REPEATING THE LOOP.

REMOVE C203 ON AN "AS-NEEDED" BASIS ONLY.
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73 de JOE
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QWCA - NCVA - SOWP - FISTS
Gordonsville, Va 22942 (Orange County)
Looking for:  Heathkit HR/HX-20, MR/MT-1,
              Collins 516F-2, 312B-4, EFJ TR Switch
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