HEATHKIT SERVICE BULLETINS - CONT
Joseph W Lutz
joelutz at JUNO.COM
Mon Jun 23 22:06:43 EDT 1997
CONTINUING:
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FEBRUARY 11, 1971
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-1
VFO DRIFT
The vfo coil has been changed to improve the drift problem experienced in
many units. The old coil [PN 40-810] should be replaced by the new coil
[PN 40-1976] whenever a unit displays excessive drift. This has been
made a permanent change in all future production.
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SEPTEMBER 14, 1972
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-2
REPEATED HETERDODYNE OSCILLATOR TUBE FAILURE
INADEQUATE USB-LSB FREQUENCY DRIFT
Change: R-212 from 220 Ohm to 330 Ohm 1/2 watt resistor [PN 1-4]. Lack
of VFO shift range can be corrected by changing the value of the FET
source resistor.
Change: R-947 from 470 Ohm to 1000 Ohm [PN 1-9].
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FEBRUARY 16, 1973
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-3
CARRIER NULL CONTROL FAILURE
Recently an improved mounting method was devised for the [PN 10-147]
controls in kit models SB-102, SB-401 and HW-101. Current production
utilizes a fiber washer for greater clearance and the case of the control
is grounded by a separate wire. We are anxious to know if this will
educe the failure rate. Please make note of any change, good or bad, and
keep us posted.
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OCTOBER 29, 1973
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-4
LOW OUTPUT ON 40 METERS
SEE BULLETIN NO: SB-102-5 DATED OCTOBER 29, 1973
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MAY 23, 1974
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-5
ALTERNATE METHOD OF NEUTRALIZING THE FINAL AMPLIFIERS
SEE BULLETIN NO: HW-100-3 DATED MAY 23, 1974.
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MAY 23, 1974
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-6
SB & HW SERIES AUDIO PREAMPLIFIER & VOX CIRCUIT
TROUBLESHOOTING GUIDE
SEE BULLETIN NO: SB-100-3 DATED MAY 23, 1974
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MAY 23, 1974
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-7
SB & HW SERIES INSTABILITY & CORRECTIVE INFORMATION
SEE BULLETIN NO: SB-100-4 DATED MAY 23, 1974
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DECEMBER 18, 1974
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-8
OSCILLATIONS OR LOW DRIVE
SEE BULLETIN NO: SB-100-5 DATED DECEMBER 18, 1974
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MAY 2, 1975
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-9
SELF OSCILLATIONS OCCURRING AFTER INSTALLATION OF
STEEL COMB BRACKETS
SEE BULLETIN NO: SB-100-6 DATED MAY 2, 1975
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MARCH 26, 1976
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-10
S-METER DRIFT
To bring the meter drift to an acceptable level, install the following:
CHANGE: R107 from 100K Ohm 1/2 Watt to 100K 1 Watt
[PN 1-28-1]
This makes the voltage divider string more stable with temperature
changes caused by internal heating.
This change will be made in future production runs.
---------------------------------------------------------------------------------------------------------------- NOVEMBER
15, 1976
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-11
LOW RECEIVER
SENSITIVITY
SEE BULLETIN NO. HW-100-7 DATED NOVEMBER 15, 1976
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******************************************************************************************
NOTE: FICHE FOR YEAR 1977 WAS NOT RECEIVED - SORRY.
******************************************************************************************
JANUARY 20, 1978
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-18
RF CHOKE IN FINAL PLATE CIRCUIT OVERHEATS OR
DIFFICULT TO NEUTRALIZE ON 10 METER & 15 METER BANDS
6146B tubes in the final amplifier may be causing this problem. To
correct, replace with 6146A tubes.
A label will be installed on the back panel of the HW-101 recommending
the use of 6146A tubes only. The 6146B tubes should not be used as a
replacement.
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FEBRUARY 2, 1978
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-19
VFO SHIFT
The trimmers on the VFO tuning capacitor tend to align at their minimum
capacitance. Therefore, the head of the screw may not be under
sufficient pressure against the spring plates of the trimmers, and
intermittant frequency shift can result. Changing C-947 from 56 to 47pf
NPO [PN 21-147] will allow the trimmers to tune to a point with tighter
compression.
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FEBRUARY 3, 1978
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-20
LOW POWER OUTPUT, S-METER DRIFT, ETC
The #44 pilot lamps presently used in the unit unbalance the
series-parallel filament line because of their 250ma current
requirements.
In each unit srvice, change the pilot lamps to type #47 [PN 412-11].
This change will be incorporated in future runs.
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MARCH 31, 1978
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW0101-21
DISTORTED AUDIO, NO CARRIER NULL OR ERRATIC
POWER OUTPUT IN VOICE MODE
This problem may be caused by V1 oscillating at approximately 65KHZ,
especially if a "GE" brand tube is used at this location.
To correct,
INSTALL: .005 uf capacitor [PN 21-57] in parallel with the .2 uf
capacitor at C3.
Install only as needed.
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APRIL 14, 1978
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-22
RELATIVE POWER METER PEGS ON 15 AND 10 METER
Diode CR-901 [PN 56-26] shuld be ounted on terminal strip BR with 1/2"
leads. This introduces a slight amount of inductance into the circuit,
which cures the problem.
The next manual level will include this instruction.
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JUNE 5, 1978
HW-101 BULLETIN NO:
SSB TRANSCEIVER HW-101-23
RELAYS REMAIN ENERGIZED AFTER TRANSMIT CONDITION
After keying the transceiver with PTT for thirty to forty seconds, a
positive voltage in excess of 10 volts appears at the control grid, pin 9
of V12, thus keeping the relays energized.
To correct the problem, replace V12 [PN411-124]. IEC Brand tubes have
been found defective in several cases, but other brands may also cause
this problem.
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Okay gang, will resume - hopefully tomorrow - with HW-101-24. Ciao!
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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