Heathkit Service Bulletins: HW-XX (Updated/Complete 1966-89)
Joseph W Lutz
joelutz at JUNO.COM
Thu Apr 30 06:39:46 EDT 1998
June 15, 1967
HW-12
Bulletin No.
80M SSB Transceiver
HW-12-1D
VFO Drift
An incorrect shipment of coils has been included in a recent production
run of the HW-12, HW-22 & HW-32.
The coil Part Number is 52-25 & has a N-750 ceramic installed inside the
can...rather than a silver mica.
The mis-manufactured coil causes drifting in the circuit...which can be
corrected by replacing with a # 52-25 of proper construction. All stock
currently on hand in the parts dept is correctly manufactured.
------------------------------------------------------------------------------------------------------------------
April 15, 1968
HW-12
Bulletin No:
80M SSB Transceiver
HW-12-2D
IF Feedback in Receive
Mode
R-121 may be changed from 12K ohm to 22K ohm 2W [PN 1-11-2] to stop
IF feedback in receive operation.
-----------------------------------------------------------------------------------------------------------------
April 18, 1968
HW-12
Bulletin No:
80M SSB Transceiver
HW-12-3D
IF
Oscillating
DELETE: (2) I-16 (5) Resistor, 4.7K OHM
ADD : (2) I-16 (6) Resistor, 4.7K OHM
DELETE: (2) I-22 (5) Resistor, 22K OHM
ADD : (2) I-22 (4) Resistor, 22K OHM
DELETE: (4) 83-69-4 (1) Circuit board, 85-69 screened
ADD : (4) 85-69-9 (1) Circuit board, 85-69 Screened
NOTE: (R91) will reduce action of the S-Meter.
------------------------------------------------------------------------------------------------------------------
September 26,
1968
HW-16
Bulletin No:
Novice Transmitter
HW-16-1
Side
Tone
When using the HW-16 with a VFO sometime a partial operation of the
sidetone oscillator takes place due to an increased loading on the bias
voltage. This can be corrected by changing R-69 from a 120K hom resistor
to a 220K ohm resistor [PN 1-29]. Also, the original schematic shows
R-16 as a 4700 ohm resistor which is incorrect. R-16 should be shown as
a 5600 ohm resistor.
--------------------------------------------------------------------------------------------------------------------
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].
----------------------------------------------------------------------------------------------------------------
October 3, 1968
HW-17 Bulletin No.
2 Meter Transceiver HW-17-1
An Alternate Method for Adjusting Coil L-15 in the T-R
Switching Circuit is as follows:
1. Tune up transmitter for maximum output per manual
instructions, [approximately 20 volts R.F. across a 50 ohm resistive
load].
2. Put R.F. probe at "ANT" terminal of the receiver circuit
board, [100 pf disc capacitor should be connected to terminal at this
time].
3. Key microphone and tune L-15 for minimum R.F. indication,
[R.F. voltage will normally be between 2.5 and 3.5 volts but in no case
should it exceed 4.0 volts].
NOTE: In some cases it has been necessary to change C-128 from a 15 pf
to an 18 pf capacitor to reach a null point with coil L-15.
--------------------------------------------------------------------------------------------------------------------
December 17, 1968
HW-17 Bulletin No:
2 Meter Transceiver HW-17-2
Audio, Transmit, Meter Sensitivity, Spot
Signal Mods.
Transmit-Receiver Audio circuits.
1. Change C233 from 10 uf to 50 uf. [Emitter circuit of Q11].
2. Ground the Emitter of Q12 to nearest circuit board Ground
Foil.
[These changes were made to increase thepercentage of
Modulation,
improve Low Frequency Response, and stabilize any
tendency toward instability].
3. Change R225 from 3.3 k-ohm to 1 k-ohm [Emitter circuit of
Q8].
4. Change R245 from 47 ohm to [1] k-ohm [Emitter circuit of
Q13].
///NOTE: Fiche shows change to ' k k-ohm'///
5. Add an insulated Jumper Wire from CY1 to CF2 terminal strips.
[Optional].
NOTE: The Bias Control must also be set properly as per manual
instructions, or the Red Lead may be disconnected from ground lug CG and
a Milliammeter inserted in series from Red Lead to CG and Bias Control
adjusted to a reading of 80 ma.
(These changes were made to reduce the residual hum).
Transmit Circuit
1. Remove ALL BUT 3-1/2 TURNS from coil L9 (Plate Circuit of
V1B).
(This change is made to change the resonance from 48 to 72
mc).
NOTE: We do not have a 72 mc coil in strock at this time, BUT if you
have sent in your Registration card this part will automatically be
forwarded to you as soon as possible.
Optional Changes
1. To increase Meter Sensitivity on Receiver, reduce the value
of R307 and readjust METER ZERO control. (With a jumper
wire across R307
the meter will read full scale at approximately 25 uv input
at the
Antenna).
2. To reduce "SPOT SIGNAL" signal injection: unsolder the lead
of R107
and lift from the circuit board, Solder Island A, on
transmitter circuit
board. Solder one end of an insulated hook-up wire to the
exposed
lead of R107 and connect the other end of this wire to the
solder pin
at Solder Island U, to which the VIOLET wire is connected.
-------------------------------------------------------------------------------------------------------------------
July 21, 1969
HW-17A Bulletin
No:
2 Meter Transceiver HW-17-3
Heath VFO Operation
Diode originally called for in HW-17A Manual (page 81) to be installed in
HG-10 VFO Oscillator cathode keying circuit should not be used as this
causes erratic or complete loss of oscillator output. Green lead in VFO
should be connected to Lug 3 of terminal strip A.
--------------------------------------------------------------------------------------------------------------------
August 25, 1969
HW-17 Bulletin No:
2 Meter Transeiver HW-17-4
VFO Operation
Some interaction has occurred when the HG-10 VFO is used with the HW-17
Transceiver. With the present system, there is considerable RF loss in
the VFO. This is caused by having the VFO switched effectively through
three diodes in series, which lowers the DC voltage in the cathode
circuits of the VFO.
To cure this, leave the VFO modifications as per the HW-17 manual stand
as is. On the VFO PLUG, remove the wire going to pin 8 and reconnect to
pin 7. In the HW-17, connect and solder a wire from pin 7 of SOCKET CT
to point D on the Receiver circuit board. This HW-17 change should be
picked up in the manual at next printing.
The modified circuit will now bypass the T-R switch circuit. The only
way to SPOT with the VFO is with the VFO Function switch.
Since the ration of HW-17 sold to those used with the HG-10 is so small,
it is felt that a manual insert is not required.
-------------------------------------------------------------------------------------------------------------------
June 15, 1967
HW-22 Bulletin No:
40M SSB Transceiver HW-22-1D
VFO Drift
An incorrect shipment of coils has been included in a recent production
run of the HW-12, HW-22 & HW-32.
The coil Part Number is 52-25 & has a N-750 ceramic installed inside the
can...rather than a silver mica.
The mis-manufactured coil causes drifting in the circuit...which can be
corrected by replacing with a # 52-25 of proper construction. All stock
currently on hand in the parts dept is correctly manufactured.
------------------------------------------------------------------------------------------------------------------
April 15, 1968
HW-22 Bulletin No:
40M SSB Transceiver HW-22-2D
IF Feedback In Receive Mode
R-121 may be changed from 12K ohm to 22K ohm 2W [PN 1-11-2] to stop
IF feedback in receive operation.
------------------------------------------------------------------------------------------------------------------
June 24, 1988
HW-24 Bulletin No:
Twin-Bander Mobile Transceiver HW-24-1
Increasing Coverage of Receiver
The following modification increases the frequency coverage of the
receiver section only. The coverage will incease as follows:
From To
VHF: 144-147.995 MHz 130-169.995 MHz
UHF: 438-449.995 MHz 360-489.995 MHz
Procedure
During this procedure, you'll reset the Tranceiver. This will erase the
data stored in memory. If you want to save the data, turn the
Transceiver on and write down the contents of each memory location before
beginning.
-- Disconnect the power plug from the Transceiver.
-- Refer to Pictorial 1 and remove the mounting stand.
////Pictorial shows removal of the [5] bottom plate screws////
-- Remove the five screws that secure the bottom plate.
-- Refer to Pictorial 2 and position the bottom plate as shown.
////Pictorial shows bottom plate laid beside the xcvr and to the left
of it - speaker
remains connected.////
-- To increase the 144 MHz band coverage, refer to Inset #1 and cut the
lead of
diode QD22. Position the leads so they won't accidentally touch
each other.
////Insert just shows the QD22 & QD24 Lead to be cut.////
-- To increase the 450 MHz band coverage, refer to Inset #1 and cut the
lead of
diode QD24.
-- Apply power to the Transceiver and turn it on.
CAUTION - The next step resets the Ransceiver and clears all memory
locations. Have you written down the contents of the memory locations
that you want to save? This is your last chance.
-- Refer to Inset #2 of Pictorial 2 and briefly short together the two
terminals as shown. The current display will disappear and the
display frequencies will be reset to 146.000 MHz and 446.000 MHz.
////Inset #2 shows the two terminals to be shorted. They are at the
center of the
bottom of the xcvr, to the right of the QD22/24 diodes and
multi-wire connector.////
-- Turn off the Transceiver and disconnect the power.
-- Reinstall the bottom plate and wire mounting stand.
The modification of the Transceiver is completed.
--------------------------------------------------------------------------------------------------------------------
October 27, 1989
HW-24 Bulletin No:
Twin-Bander Mobile Tranceiver HW-24-2
Lithium Battery Source
Heath Parts Replacement does not stock the lithium battery for this unit.
A source for the lithium battery is:
DIGI-KEY
701 Brook Avenue South
Thief River Falls, MN 56701
Battery type CR2032
--------------------------------------------------------------------------------------------------------------------
June 24, 1988
HW-24HT Bulletin
No:
VHF/UHF Transceiver HW-24HT-1
Increasing The Frequency Coverage of The Receiver
The HW-24HT Transceivers now shipping have a VHF range of144.00 to
147.995 MHz and a UHF range of 438.00 to 449.995 MHz. However, the
Transceiver can be programmed to receive a VHF range of 130.00 to 169.99
MHz. The UHF range can be changed to 340.00 to 379.99 MHz or 360.00 to
399.99 MHz in addition to 400.00 to 469.99 MHz. Here's the programming
procedure needed to operate the receiver in the wide band mode. Refer to
the HW-24HT Owner's Manual [PN 595-4141] for general operating
procedures.
-- Set the Channel step rate to 12.5 khz [see page 2-32 in owner's
manual].
-- Select A VFO and dial a frequency of 14X.XX75 [X=Don't care].
-- Press FUNCTION button and the 7/RPT button. The display shows a "-"
offset.
-- Press FUNCTION button and then 8/+/- button. This selects the "+"
offset.
-- Press FUNCTION button and the */ENT button.
-- Again, press FUNCTION button and then */ENT button.
NOTE: The receiver is now set to receive frequencies from 130.00 to
169.99 MHz on VHF and 340.00 to 379.99 MHz and 400.00 to 469.99 MHz on
UHF. To select the UHF range from 360.00 to 399.99 MHz and 400.00 to
469.99 MHz, continue with the following steps.
-- Press the RCL button.
-- Press the FUNCTION button and then the C/BAND button.
The VHF range from 130.00 to 169.99 MHz and the UHF range from 360.00 to
399.99 MHz and 400.99 to 469.99 is now set. NOTE: To again select the
340.00-379.99 UHF range, you'll have to press the RESET button (to return
to narrow band mode) and then repeat the first 6 steps.
The second production of HW-24HT Transceivers will be wired to receive
the wide band of VHF and UHF frequencies. To determine if the
Transceiver is wired for wide band operation, try entering a frequency
between 130 and 144 MHz; if the frequency is accepted, the transceiver is
wired for wide band operation.
-------------------------------------------------------------------------------------------------------------------
October 28, 1988
HW-24HT Bulletin
No:
VHF/UHF Transceiver HW-24HT-2
Antenna and Battery Case Part Numbers
Replacements for the antenna and batter case are available from Heath
Parts Replacement. The Heath part numbers are:
Antenna: 969-1391
Battery Case 969-1394
--------------------------------------------------------------------------------------------------------------------
October 27, 1989
HW-24HT Bulletin
No:
UHF/VHF
Tranceiver HW-24HT-3
Lithium Battery Source
Heath Parts Replacement does not stock the lithium battery for this unit.
A source for the lithium battery is:
DIGI-KEY
701 Brook Avenue South
Thief River Falls, MN 56701
Battery type CR2032
--------------------------------------------------------------------------------------------------------------------
June 15, 1967
HW-32 Bulletin No:
20M SSB Transceiver HW-32-1D
VFO Drift
An incorrect shipment of coils has been included in a recent production
run of the HW-12, HW-22 & HW-32.
The coil Part Number is 52-25 & has a N-750 ceramic installed inside the
can...rather than a silver mica.
The mis-manufactured coil causes drifting in the circuit...which can be
corrected by replacing with a # 52-25 of proper construction. All stock
currently on hand in the parts dept is correctly manufactured.
------------------------------------------------------------------------------------------------------------------
April 15, 1968
HW-32 Bulletin No:
20M SSB Transceiver HW-32-2D
IF Feedback In Receive Mode
R-121 may be changed from 12K ohm to 22K ohm 2W [PN 1-11-2] to stop
IF feedback in receive operation.
-------------------------------------------------------------------------------------------------------------------
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 R-200 and C-204
with an oscilloscope. If you see a negative 12-Volt pulse, 4
milliseconds wide, remove C-203.
C-203 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 the 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 R-203 and sends a negaitve pulse through C-203/R-200, the MIC GAIN
Control, C-14 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 C-203 on an "AS-NEEDED" basis only.
--------------------------------------------------------------------------------------------------------------------
September 29, 1982
HW-32 Bulletin No:
20 Meter SSB Transceiver HW-32-2
Finals Self-Oscillate
+ + + + Information not available at this time + + + +
--------------------------------------------------------------------------------------------------------------------
July 31, 1987
HW-99 Bulletin No:
Novice CW Tranceiver HW-99-1
Schematic Corrections - Oscillator Board
On the oscillator board schematic in the HW-99 Blue Book and the Assembly
Manual [PN 595-3185] make the following corrections:
C243: "47 pF" to read "220 pF"
C252: "68 pF" to read "6.8 pF"
Mark these corrections on your shop schematics for future reference.
-------------------------------------------------------------------------------------------------------------------
March 31, 1988
HW-99 Bulletin No:
Novice CW Transceiver HW-99-2
No Audio at Headphones; Audio at Speaker Okay
In the HW-99 Assembly Manual [PN 595-3185], Illustration Booklet, page
36, Pictorial4-8 shows the labels at legs 2 and 3 of phone jack J1
interchanged; the wiring shown is correct.
--------------------------------------------------------------------------------------------------------------------
November 28, 1988
HW-99 Bulletin No:
Novice CW Transceiver HW-99-3
VFO Jumps OFF Frequency
If the VFO jumps off frequency when copying a station, the +12 VDC supply
may be unstable. If so, try another 12 volt regulator at U1 [PN
442-674].
--------------------------------------------------------------------------------------------------------------------
November 28, 1988
HW-99 Bulletin No:
Novice CW Transceiver HW-99-4
Low Power On 10 Meters - Inadequate Drive From BFO
Within the past few months, low BFO output has been a problem with almost
every new HW-99 kit that's been reeived in Factory Service. Replacing
Q203 [PN 417-863] and T201 [PN 52-193] in the BFO buffer circuitry on the
oscillator board has always corrected the problem.
--------------------------------------------------------------------------------------------------------------------
Okay troops. That is all I show for the HW-XX series 1966-89 [and which
I have available to me at this time]. Time to get back to finishing the
basement. Enjoy!
--------------------------------------------------------------------------------------------------------------------
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