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!
--------------------------------------------------------------------------------------------------------------------

_____________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
Or call Juno at (800) 654-JUNO [654-5866]

--- --- --- --- --- --- --- --- --- --- --- --- --- --
To subscribe: listserv at listserv.tempe.gov
and in body: subscribe HEATH yourfirstname yourlastname
To unsubscribe:  listserv at listserv.tempe.gov
and in body: signoff HEATH
Archives for HEATH: http://www.tempe.gov/archives
--- --- --- --- --- --- --- --- --- --- --- --- --- --




More information about the Heath mailing list