Heathkit Service Bulletins: HW-2021 (Complete 1966-89)
Joseph W Lutz
joelutz at JUNO.COM
Wed May 6 04:45:21 EDT 1998
December 31, 1975
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-1
12.5 Line Shorting To Ground Foil
To prevent the switch actuator from shorting the 12.5V line to a ground
foil near SW1, place a piece of fish paper [PN 75-203] at the location
shown in the drawing below.
///Drawing shows the fish paper being placed on the component side of the
(back cover) at SW1.///
Also, install fish paper on the rear of the speaker to prevent components
from shorting to the speaker.
The transceiver should be checked for intermittent shorting after the
case is installed by squeezing the front and back of the case while
transmitting. The transmitter output may be monitored using a frequency
counter.
Receiver Inoperative
Check Q12 [PN 417-154] in the Battery Saver circuit for an open between
base and emitter.
The waveform at the emitter of Q14 is shown below. This waveform is
present when the Battery Saver circuit is operating properly.
- -
| | <---------300mS-------> | |
______| |___________________ | |______
/
1 mS
///NOTE: Sorry for poor drawing. The 1 mS pulse does not have broken
lines///
Oscillator Multipliers Output Low
If insufficient output is found at Q16, Q17 or Q18, replace the
transistor in the low gain stage with a Part #417-172 transistor. This
transistor is only to be installed as needed and is NOT EXPECTED to be a
production change in later runs.
-----------------------------------------------------------------------------------------------------------------
January 8, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-2
Low Oscillator Multiplier Output
Change: Q16, Q17 and Q18 from Part #417-134 to Part #417-293.
------------------------------------------------------------------------------------------------------------------
January 8, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-3
Circuit Change To Prevent Q12 Failure
To prevent the failure of transistor Q12 in the battery saver circuit,
install a 10 ohm 1/4 watt resistor [PN 1-55-12] in series with the
negative lead of C39 [22 uF] in the emitter circuit of Q11. Install as
shown.
//Note: Drawing shows negative lead of C39 lifted from the PCB and the
10 ohm resistor placed in series with that lead. The remaining lead of
the 10 ohm resistor is then reconnected to the PCB where the - lead of
C39 was previously.//
--------------------------------------------------------------------------------------------------------------------
January 8, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-4
Poor Fit Between Circuit Board and Case
Units in which the circuit board mounting hole near the top of the board
will not align with the cabinet boss, can be corrected by either of the
following methods:
Method #1: Shave the left edge of the circuit board in the area of SW3,
enough to allow hole A to align with the cabinet boss. Be careful not to
damage the foil pattern on the bottom of the board.
Method #2: A. Use a small rat-tail file and file hole A (board mounting
hole) into an oblong shape, 1/8" in the direction shown. [[[Parallet to
R29 & R26, file out towards R26]]] File only in the indicated area to
prevent opening the plate-thru foil in this hole.
B. Reheat the connections at the lugs of the Squelch, R26
and Volume, R29, controls and tilt these controls sideways in the
direction indicated just enough to permit the circuit board to be shifted
away from the cabinet side.
[[[Tile the controls in the direction of where SW3 is - or in the same
direction you filed hole A mention above]]].
------------------------------------------------------------------------------------------------------------------
January 8, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-5
Battery Pack Shorting To Case
To prevent the spring contacts of the battery housing from shorting to
the case near the bottom end of the circuit board, cut the existing
insulating paper in the center as shown in the drawing. Move the top
half of the insulating paper 1/4" toward the top of the case.
[[[Sort of explains itself - Cut the paper in the center and move it 1/4"
towards the top]]]
------------------------------------------------------------------------------------------------------------------
January 8, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-6
High 2ND Harmonic Output
Units with high 2nd harmonic output - could be as great as 4 watts -
could be caused by improper type diodes at D14 and D15. These diodes
must be [PN 56-24].
Units were shipped with the wrong type diodes in packages marked "56-24".
The improper diode is a clear glass package similar to the #56-56. The
#56-24's are blue.
Other circuits in this unit which use the #56-24 diode will operate
properly with these "wrong-type" diodes installed, therefore, it is not
necessary to change all the diodes.
------------------------------------------------------------------------------------------------------------------
January 26, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-7
Injection Oscillator
To insure that the injection oscillator transistor Q15 will start up on
initial application of power, the following change should be made to
units received for service:
Change: R65 From: 680 Ohm To: 1200 Ohm [PN
1-70-12]
----------------------------------------------------------------------------------------------------------------
January 26, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-8
Front End Oscillation
Problems have been experienced where oscillation may occur in the
receiver front end. While the oscillation is difficult to detect, and
does not occur in all units, the following changes should be made to
units received for service:
Change: R21 From: 47 Ohm To: 1 uH Choke [PN
45-80]
Q1, Q2 417-240
417-274
Q3, Q21 417-240
417-274
Front end alignment should be rechecked after making these changes.
-------------------------------------------------------------------------------------------------------------------
January 26, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-9
Schematic Errors
The change shown below affecting component placement should be made to
your HW-2021 schematic.
///The schematic shows the change from having the diode [PN 38-24]
connected to the collector of Q7 going in series with a 2200 ohm
resistor, which then connects to the Base of Q9 (I think - very small and
blurred). This is changed to having the 2200 ohm resistor connected to
the collector of Q7, then going in series to the diode, which then
connects to the Base of Q9.///
--------------------------------------------------------------------------------------------------------------------
January 26, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-10
Q9 Shorting To Ground Through
Metalized Case
Kits which have the HWM-2-21-1 Modification Kit installed may have Q9
shorting to the metalized case boss nearby. When the board is shifted,
lead ends may be brought into contact with the metalized board mounting
boss.
To correct this problem, the metalized finish should be scraped away for
1/8" from the top edge of the boss.
--------------------------------------------------------------------------------------------------------------------
February 23, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-11
Diode Change
*********This Bulletin is stamped INVALID and that the Varactor diode at
VD1 is to remain Part # 56-632.*********
--------------------------------------------------------------------------------------------------------------------
February 24, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-12
Receiver Oscillating and Spurious Outputs
The following changes should be made to all HW-2021's for service:
1. Change:
C64 from 470 pf to 47 pf [PN
21-710]
C57 from 47 pf to 68 pf [PN
20-76]
C103 from 47 pf to 15 pf [PN
21-111]
C67 from 470 pf to 47 pf [PN
21-710]
R64 from 680 ohm to 1 K [PN
1-2-12]
R65 from 47K ohm to 330 K [PN
1-93-12]
R21 from 47 ohm to 1 mh choke [PN
45-80]
Q16, Q17, Q18 from [PN 417-134] to [PN 417-293]
Q1, Q2 from [PN 417-240] to [PN 417-274]
2. Remove C72.
3. Install a 10 ohm [PN 1-55-12] in series with C39.
4. Use a SHORT piece of wire to connect IC1 pin 4 and 14 together,
taking care
not to touch other foils.
5. Remove the 6 1/2" grey wire from terminal 3 of the push-to-talk
switch and the
B+ hole on the circuit board. Replace this lead with a 2 1/4" grey
lead from the
B+ hole to the common junction of R24 and R28. Make this lead a
short and
direct as possible.
6. Install a spring clip [PN 258-5] at the upper right hand corner of
the circuit board
(see drawing below). The clip should be arranged so that it will
touch the case
side when the board is installed.
//Drawing shows the clip mounted on the foil side of the PCSA and then
bent down to approx a 45 deg angle to allow it to touch the case side as
stated.//
Some of the changes made in earlier HW-2021 Bulletins are also
incorporated in this Bulletin. However, note that R64 is being changed
to a different value than used in Bulletin HW-2021-7.
After making these changes, the units will have greatly improved squelch
sensitivity, the receiver sensitivity specification will be easily met,
and the transmitter will deliver 1.8 to 2.0 watts out typically.
------------------------------------------------------------------------------------------------------------------
February 27, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-13
Oscillator Will Not Start On All Crystals
The following change should be made to all HW-2021's received for service
to insure that Q15 will always start when different crystals are
installed at Y2 through Y6.
Change: R63 from 4.7K ohm to 6.8K ohm [PN 1-78-12]
-------------------------------------------------------------------------------------------------------------------
March 2, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-14
Insufficient Tripler Output
Some of the Part #417-293 transistors used at Q16 may not provide
sufficient output to the following stages. To assure sufficient drive,
make this change:
Change: R65 from 47K ohm to 100K ohm [PN 1-32-12]
--------------------------------------------------------------------------------------------------------------------
March 2, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-15
Grounding Circuit Board To Metalized Cases
The ground foil pad below Hole A on the main circuit board (See Bulletin
No: HW-2021-4) should be built up with solder to assure good ground
contact with the metalized stud boss and the metalized case.
--------------------------------------------------------------------------------------------------------------------
April 2, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-16
Unstable In RX or TX Mode
When operating this unit from an external DC supply or on internal
batteries that have a full-load voltage of 11 volts or less may cause the
unit to become unstable in either the transmit or the receive mode or
both. This is due to the power supply impedence being too high. This
impedence is a integral part of the circuit and must be low for the unit
to operate properly.
-----------------------------------------------------------------------------------------------------------------
April 29, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-17
Ground Connection to Case
Proper performance of the HW-2021 depends upon a good ground connection
of the printed circuit board to the metalized mounting bars on the case.
Check to make sure that the metalization is intact on the TOP of the
metalized boss where it makes contact with the printed circuit board.
--------------------------------------------------------------------------------------------------------------------
April 29, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-18
Poor Sensitivity
The input coil [PN 40-1781] center taps have been breaking, causing
sensitivities of 5 uV or worse. Steps have been taken to correct the
coil breakage problem.
-------------------------------------------------------------------------------------------------------------------
October 1, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-19
Q24 Shorting
Q24 can be easily shorted and destroyed if a meter test probe slips off
TP2. To prevent this, insert a 1" length of sleeving [PN 346-1] on TP2.
----------------------------------------------------------------------------------------------------------------
October 1, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-20
Unable To Center Netting Capacitors
***************Superceded by Bulletin No:
HW-2021-22**************************
-----------------------------------------------------------------------------------------------------------------
October 1, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-21
Reducing Receiver Oscillations
The conductive coating around the antenna jack can be scraped away during
assembly or servicing of the HW-2021, causing a poor ground at the
antenna jack. A good ground at the antenna jack will significantly
reduce receiver oscillations and increase receiver sensitivity.
If receiver oscillation is a problem, remove the flat washer on the
outside of the case from the antenna jack, and reinstall it on the jack
on the INSIDE of the case where it can bear against the case's conductive
coating.
The threaded length of the jack is not long enough to take another flat
washer on the outside of the case, so care should be taken when
tightening the antenna jack nut against the plastic case.
-------------------------------------------------------------------------------------------------------------------
November 10, 1976
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-22
Step-By-Step Service Procedure
1. Remove the four (4) screws from case back.
2. Loosen the thumb nut on the antenna.
3. Remove the wires to the antenna, speaker, LED and touch tone encoder
(if included). Use needle nose pliers to remove the wires for CB
connector pins.
4. Remove the three knobs and loosen the control nuts.
5. UNSOLDER and remove OFFSET switch. Be careful not to melt the
switch.
6. Remove the three screws securing the circuit board and remove the
board
from the case.
7. Visually inspect the board for any cracked capacitors or resistors.
Check RFC
9 and RFC 11 to be sure it has been wrapped with three turns of
enameled
magnet wire. Check diodes D14 and D15 to be sure they are Part #'s
56-24.
Some kits were shipped with Part #56-56's by misake. The Part #'s
56-24 and
some 56-56's are blue in color.
8. Check to make sure all mods have been installed. See modification
list
included with this bulletin.
9. If a circuit board holder is available, use this to hold the circuit
board while
repairing. Be sure metal sides of the holder are insulated from the
circuit
board.
10. Hook up an external test speaker and power supply. (While radio is
being
repaired, have the nicad battery pack on charge). The power
supply should
be set to supply approximately 14 VDC.
11. Turn the receiver on. Check the voltage at RFC 1. It should be
around 10.7
to 11.2 volts. (If not, check that Q14 and Q12 are installed
properly). Turn
the squelch control clockwise till the noise disappears and
recheck your
voltage at RFC 1. It should pulsate. This indicates the
batter-saver circuit
is working.
12. Turn the Selector switch to the crystal position of 146.94 crystal.
13. Take the VTVM and RF probe and apply the probe to the top of R11.
On the 1.5
volt scale, adjust L7 (all at the top), L8 and L9 for a peak
reading. It should
be around 1.5 VRF, no less than 1 volt. Remove probe.
14. Set L4 and L5 so that their slugs are even with the top of the coil
form. Adjust
L1, L2 and L3 for peak noise by ear. Then connect an FM signal
generator to
the antenna PCB connectors. Tune the generator to 146.94 and use
an AC
VTVM cross the speaker terminals to adjust L1, L2 and L3 for a
peak reading.
15. Check the sensitivity to be sure it is .75mV for 20 dB quieting.
16. Preset coils L11, L12, L13, L14, L21 and L22 to the top of the coil
form. L15
and L18 should be preset one turn up from the bottom. L16, L17
and L19
should not have any slugs. If there is, remove and discard the
slugs.
17. Connect the RF probe to the top of R103 and connect a 51 ohm dummy
load
to antenna pins. Key the transmitter and adjust L11, L12, L13
and L14 for a
peak. To be sure you are on the correct frequency, connect a
frequency
counter around L14. This can be accomplished by taking three or
four
turns of #22 solid hook-up wire and connecting it across your
counter test
lead. Be sure your test lead is COAX.
Another way of checking is, normally L11 and L12 are 1/8" down
from top of
coil forms. L13 and L14 will vary between 1/16" and 1/8".
18. Move the RF probe to the 51 ohm resistor. Key the transmitter, and
with the
VTVM set on the 15 volt scale, adjust L15, L18, L21 and L22 for a
peak
reading. Normally, for 1-watt output, you need 7 VRF.
19. Connect coiled wire from frequency counter around 51 ohm resistor.
Adjust
appropriate trimmer cap for correct frequency, Trimmer should be
able to
swing through frequency. If not, change trimmers to Part #
31-81.
20. After all repairs are made and the transceiver is aligned, turn the
circuit board
over and clean off the rosin with a stiff brush (1" chip brush or
equivalent), and
denatured alcohol. Set the board aside temporarily.
21. Find the bottom case half. Check to see if the fish paper is
installed at the
correct locations. Set aside.
22. Find the top case half. Check to see if the fish paper is
installed correctly.
Make sure lead dress of the microphone and external antenna jack
go under
the clips that hold down the speaker (Figure 4-2). Position the
wire going from
the external jack to the Rubber Duckie behind the external jack
as shown in
Figure 4-2. Be sure the ground lug on the antenna jack is not
shorting to the
shorting bar on the jack.
23. Take the PCB connectors on the speaker leads and make sure they are
as
short as possible. This is to prevent any possibility of them
shorting to the
antenna jack once the case is installed.
24. Take all the PCB connectors and crimp them slightly with long-nose
pliers to
insure a tight fit. Make sure no solder has run down into the
connector.
25. Install the circuit board into the bottom case, making sure the
control nuts
are attached to the control shafts as the board is installed.
26. Install the three screws to secure the board. Be sure the
screwdriver does
not slip and damage L1.
27. Tighten control nuts on the control shafts.
28. Install the offset switch. Bend the wires over so they touch the
top of the lugs.
Tack solder these wires. This makes it easier to remove the
switch at a later
time, if necessary.
29. Install the Battery pack.
30. Connect the appropriate PCB connector and wires to the proper
locations.
31. Temporarily install the case top half to the bottom half. Turn on
the trans-
ceiver and check for any receiver oscillations. If none, proceed
to next step.
If receiver oscillations occur, pull the case up slightly and
adjust L1, L2 and
and L3 slightly until oscillations are minimum.
32. Install the case halves together along with the PTT switch actuator.
Install
the four screws on the bottom case and tighten. Check to see that
the PTT
switch works freely. If not, reopen the case, loosen the two
screws that
hold the PTT switch and push the switch backward or forward,
depending
on whether the transmitter is keyed all the time, or does not key
at all.
Retighten the switch and reinstall the case halves.
33. If a Bird wattmeter is handy, along with a 50 ohm load; check the
power
output, using the external antenna jack. Power output should be
one watt
or more (usually 1.5).
34. Check over all operations by giving a radio check into a monitor
such as an
HW-202. Be sure to use the 51 ohm dummy load.
Modifications To Be Installed In HW-2021's
1. C64 changd from 470 pF to 47 pF.
2. R63 changed from 4.7K to 6.8K; install 100 uH choke [PN 45-604] in
series with
this resistor.
3. R65 changed from 47K to 100K.
4. R64 changed from 680 ohms to 1K. Remove 1 mH choke in series with
this
resistor.
5. C57 changed from 68 pF to 47 pF [PN 21-710].
6. C103 changed from 47 pF to 15 pF.
7. C67 changed from 470 pF to 47 pF.
8. R21 chagned from 47 ohms to 1 mH choke.
9. Q1, Q2, Q3 and Q21 changed from Part #417-240 to Part #417-274.
10. Q16, Q17 and Q18 changed from Part #417-134 to Part #417-293.
11. Add a spring clip to circuit board foil.
12. Add jumper wire between pins 4 & 14 of IC1.
13. Add 10 ohm resistor in series with C39.
14. Reroute gray wire from SW1-SW3 to junction of R24 and R28.
15. Remove C72.
16. D14-D15 -- Part #56-24.
Part No. Quantity Description
----------- ------------ ----------------
417-274 4 40673
417-293 3 2N5770
1-84-12 1 100K ohm 1/4 watt
1-2-12 1 1K ohm
1-78-12 1 6.8K ohm
1-55-12 1 10 ohm 1/4 watt
20-76 1 68 pF
21-170 3 47 pF
21-111 1 15 pF
45-80 1 1 mH choke
258-5 1 clip
45-604 1 100 uH choke
If C57 still will not bring crystals within specs, change C49, C51-C54 to
Part #
31-81 trimmers.
-----------------------------------------------------------------------------------------------------------------
March 3, 1977
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-23
Low Battery Life
+ + + + Information not available at this time + + + +
-------------------------------------------------------------------------------------------------------------------
March 15, 1977
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-24
R14 Burning Up
+ + + + Information not availabe at this time + + + +
-------------------------------------------------------------------------------------------------------------------
April 10, 1978
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-25
Brass Inserts Strip Out of Plastic Bosses
Heat the installed insert with a soldering iron and crimp the plastic
boss with pliers. The warm plastic will be reformed to hold the insert
securely.
--------------------------------------------------------------------------------------------------------------------
August 21, 1978
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-26
Output Frequency Low
If the output frequency is 3 to 4 kHz low, check Q15. It should be a
Motorola type MPS6521 [PN 417-172] with GOLD-colored leads. (If
unavailable, substitute with a 2N2369, [PN 417-154].
Make this change only as needed.
--------------------------------------------------------------------------------------------------------------------
August 30, 1978
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-27
Q14 Fails After Final Assembly
When the shield wires of the antenna coax cable to lug 1 of J201 are too
long, they may short to the anode of LED 201 when the case halves are
joined together.
To correct:
Shorten the shield wires and add a piece of sleeving [PN 346-1].
-------------------------------------------------------------------------------------------------------------------
November 22, 1985
HW-2021 Bulletin
No:
Hand Held Transceiver HW-2021-28
Blue Book Update - 51 Ohm Resistive Load
In the HW-2021 2-Meter Transceiver Blue Book, page 9, change the part
number of the 51 ohm load resistor:
From [PN 1-43-1] to [PN 6-510-1]
--------------------------------------------------------------------------------------------------------------------
That's all I show for the HW-2021 (1966-89). Enjoy!
73 de Joe W7LPF/4 [NNN0KUU]
QWCA - SOWP - NCVA - FISTS - RCC
Gordonsville, Va 22942 [Orange Co]
Wanted: SB-614 & SB-644[A]
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