Heathkit Service Bulletins: HW-202 (Complete 1966-89)
Joseph W Lutz
joelutz at JUNO.COM
Fri May 1 05:29:46 EDT 1998
August 10, 1973
HW-202 Bulletin
No:
2 Meter FM Transceiver HW-202-1
Distorted Receiver Audio
In the first run of HW-202's there exists a possibility of distorted
audio due to C325 & C327. In the subsequent kit production, these have
been eliminated.
If C325 & C327 are installed, they should be removed.
--------------------------------------------------------------------------------------------------------------------
August 14, 1973
HW-202 Bulletin
No:
2 Meter FM Transceiver HW-202-2
L208 Does Not Peak Properly
If L208 does not peak properly, one can try substituting C278 (18pf) disc
with a 15pf disc. This coil normally peaks 3-4 turns up from bottom of
coil, while L209 normally peaks very close to circuit board. RF voltage
at point AC with 51 ohm load installed should be 3 1/2 to 4 volts for
proper amplifier drive.
This change will be incorporated into future production.
--------------------------------------------------------------------------------------------------------------------
October 26, 1973
HW-202 Bulletin
No:
2 Meter Fm Transceiver HW-202-3
Corrections For Low Output Power And
and Spurious Radiation
The following changes should be made to all HW-202 transceivers received
for repair.
A regular modification kit [HWM-202-1] will be available after the 14th
of December but if you have parts available you can make the changes now.
Complete sets of parts are not available at this time and parts orders
should be for the MOD KIT ONLY.
All current production is being changed and insert sheets are being
included in the manuals. If you need insert sheets order No. 591-1296.
Transmitter Board Changes
Parts Needed
Quantity Part No Description Schematic
Location Value
----------- ---------- ---------------- ---------------------------- --------
1 1-69 .5W Comp Res
R-229 18K ohm
1 1-118 .5W Comp Res R-234
82 ohm
1 1-130 .5W Comp Res R-236
8.2 ohm
1 21-3 500V Cer Cap C-279
10 pF
1 Ft. 348-2 Magnet Wire
RFC-205 4 turns
1 206-444 Coil Cover L-205
Refer to the transmitter board schematic for the following changes:
1. Remove the 100K resistor at R-229 and install [1] 18K ohm resistor.
2. Remove the 390 ohm resistor at R-234 and install [1] 82 ohm resistor.
3. Remove the 33 ohm resistor at R-236 and install [1] 8.2 ohm resistor.
4. Remove the 4.7 pF capacitor at C-279 and install [1] 10 pF capacitor.
5. Remove the RF choke at RFC-205. REmove the 2 turns of magnet wire.
Rewind
4 turns of magnet wire on the ferrite bead as shown in the
pictorial. Reinstall
the RF choke at RFC-205.
[ ] Cut a 6" length of magnet wire. Thread this wire through
the large
ferrite bead so there are four complete loops through the
bead.
Form the loops down against the bead as neatly as
possible. Be
careful not to damage the wire coating.
[ ] Cut the leads to 1/2". Then scape 1/4" of the coating from
the end
of each lead. Use a knife blade. Discard the cutoff
wire.
6. Install [1] coil cover at L-205 by cutting off one lug of the cover
and either drill
a hole in the circuit board at the ground foil near the edge of the
circuit board or
just wrap the lug over the edge of the circuit board and solder the
lug to the
ground foil.
7. Connect the bare wire jumpers to the foil pads indicated in the
pictorial.
NOTE: if you have any difficulty identifying the foils to which
the bare wire should be soldered, refer to the foil-side view
of the transmitter circuit board
on Page 130 of the Manual. Interconnect C207, C209, C212, C214,
C216 and
C218. Make sure the bare wire does not touch the soldered
connections of any
other components.
Power Amplifier Board Changes
Parts Needed
Quantity Part No Description Schematic
Location Value
----------- ---------- ---------------- ---------------------------- --------
2 45-38 RF Choke RFC 301 and
302 .295uH
4 475-10 Ferrite Beads RFC 301 and 302
1 21-154 Cap
disc C-305 .0051uF
1 25-220 Cap
Tantalum C-306 10uF
1 21-17 Cap
Disc C-317 270pF
Refer to power amplifier schematic for the following changes:
1. Remove the RF chokes at RFC 301 and RFC 302.
2. Install 2 ferrite beads on each new RF choke [PN 45-38] and install
these
chokes at RFC 301 and RFC 302.
3. Remove the 150pF cap at C-305 and install (1) .0051 uF cap.
4. Remove the 2.2 uF cap at C-306 and install (1) 10 uF tantalum.
5. Install a 270 pf cap at C-317 as shown in the pictorial.
[ ] 270 pf disc capacitor. Cut both leads to 1/4" and install the
capacitor as
shown. Solder both leads to the foil on the COMPONENT side of
the circuit
board. Then bend the capacitor over as shown.
-------------------------------------------------------------------------------------------------------------------
November 16, 1973
HW-202 Bulletin
No:
2 Meter FM Transceiver HW-202-4
Service Hint
On all units, check soldering of relay lugs to the power amplifier
circuit board.
NOTE that the punched holes may sever the foil strip. Therefore, it is
important that each relay lug is soldered to the foil on both sides in
order to avoid open circuits.
The symptoms relating to this condition will vary depending upon which
foil strip is open. The construction manual is being revised to avoid
this problem in future kits.
--------------------------------------------------------------------------------------------------------------------
March 28, 1974
HW-202 Bulletin
No:
2 Meter FM Transceiver HW-202-5
Low Power Output
L304 and L305 on PA board are being made by the Customer with "9" turns
instead of the proper 8 turns. This can cause a loss of as much as 3
watts in total output power.
These coils should be checked on every HW-202.
--------------------------------------------------------------------------------------------------------------------
November 25, 1974
HW-202 Bulletin
No:
2 Meter FM Transceiver HW-202-6
Simple Signal Injection For HW-202 Receiver Board
A common complaint when doing the receiver alignment without instruments
is "No 'S' meter reading after adjusting T-106 successfully and moving
meter lead to point S." The possible areas of trouble are many and the
customer without a signal generator is at a loss as to what to do.
By assuming that the second oscillator Q104 is working, we can check many
parts of the circuit with the following test. Using a piece of hookup
wire and a .01 mF disc capacitor connected in series, connect this
combination between G2 of Q103 and pin 1 of transformer T101. Turn the
transceiver on. If the "S" Meter now goes up scale about 2 or 2 1/2
divisions, you have just proved that everything from the bandpass filters
to the quad detector IC-102 is working. This will narrow down the
possible cause of trouble to the first mixer stage (Q-102), amplifier
stage (Q-118) or RF amplifier stage (Q-101) and from here, finding the
cause of trouble should be easy. Also, if the audio circuits are
working, this injected signal should quieten the white noise of the
receiver.
------------------------------------------------------------------------------------------------------------------
December 12, 1974
HW-202 Bulletin
No:
2 Meter FM Transceiver HW-202-7
Transmitter Oscillator Dead
Or Sluggish When Keyed
After checking crystals and Q201 for proper operation, check diodes D201
through D206. If they are banded backwards or shorted, any one may cause
the problem.
------------------------------------------------------------------------------------------------------------------
December 26, 1974
HW-202 Bulletin
No:
2 Meter FM Transceiver HW-202-8
HW-202 Preset Alignment Chart
-Transmitter Circuit Board -
All turns are started with slug at top of coil form. These are
approximate settings and some will vary.
Numbers in parenthesis are alignment sequence. Others are number of
turns down from top of coil form.
Coil Seq # Turns TP Approx Volts +
----- ----- ----------- --------- ------------------
L201 [1] 6 3/4 TP201 3.5
L202 [2] 11 TP201 3.5
L203 [3] 11 1/4 TP202 2.0
L205 [4] 13 TP203 2.5
L204 [5] 11 1/4 TP203 2.5
L206 [6] 10 TP204 1.5
L207 [7] 12 1/4 TP205 .6
L208 [8] 13 TP206 .9
L209 [9] 13 TP206 .9
-------------------------------------------------------------------------------------------------------------------
July 9, 1975
HW-202 Bulletin
No:
2 Meter FM Transceiver HW-202-9
'73 Magazine Article and Hotline
Report
The information that was printed in these magazines was not released by
the Heath Company. Heath Company has no knowledge of where the article
came from and we do not have any selectivity modification information as
the article implies.
Setting HW-202 Deviation
Equipment Needed:
FM Signal Generator [Radiometer MS-27G]
Oscilloscope [IO-103]
Audio Sine Wave Generator [IG-18]
Shop HW-202 [modified for fixed audio gain]
Step 1
The shop HW-202 and oscilloscope are calibrated and set up to recognize a
5 kHz deviation signal. This adjustment is only made once.
a] Connect an F.M. signal generator, adjusted to the shop HW-202 receive
frequency, modulated 1 kHz at 5 kHz deviation, to the shop
HW-202 antenna input.
b] Connect the oscilloscope test leads (vertical input) across the
receiver speaker (or 8 ohm resistive load).
c] Turn the "Audio" control ful CCW (beyond the "click").
d] Note the P-P voltage reading on the oscilloscope. The "gain adjust"
control
in the shop HW-202 can be adjusted to an easily remembered level
reference
as seen on the oscilloscope.
Step 2
A signal which deflects the oscilloscope to the reference P-P voltage
indicates 5 kHz deviation. The signal generator is no longer needed
except for periodic checking and recalibration.
a] Connect the audio generator test leads across the microphone input
(Pin 1)
of the unit under test (UUT). Adjust the audio generator for 20 mV
RMS, and
depress the 600 ohm switch. This simulates the microphone voltage
output.
b] Key the UUT by shorting Pin 2 of the mic jack to ground.
NOTE: For the two preceding steps, the microphone can be connected
and the
P.T.T. switch depressed.
c] Adjust the deviation control for the reference P-P voltage noted
previously.
In place of A and B in step 2, key and speak into the microphone of the
UUT. Adjust the deviation control for the P-P voltage noted previously.
Modifying The HW-202 To Provide A Fixed Audio Gain
This modification involves defeating the function of the ON-Off Switch on
the HW-202. The power switch on the companion power supply (HWA-202-1)
will then be used to turn the unit on and off.
1. Remove the ground from the bottom end of the volume control.
2. Remove the wires from the power switch connections on the volume
control.
Splice the two wires together.
3. Connect the bottom end of the volume control to one of the switch
connections.
4. Connect the other switch connection to ground.
5. Connect the 15K control [PN 10-180] across the switch terminals of
the On-Off
control.
6. With the On-Off switch in the Off position, the "Gain Adjust" control
is adjusted
for a comfortable listening level.
-------------------------------------------------------------------------------------------------------------------
July 24, 1975
HW-202 Bulletin
No:
2 Meter FM Transceiver HW-202-10
Bulb Obsolescence
The Part # 412-39 is no longer available. If replacement is necessary
use Part # 412-58 and # 413-40.
--------------------------------------------------------------------------------------------------------------------
January 26, 1976
HW-202 Bulletin
No:
2 Meter FM Transceiver HW-202-11
Poor Sensitivity, T104 Will Not Tune
A number of kits with series number 12551 have been supplied with T104
[PN 52-160] defective. The defective transformers have pins 1 and 3
reversed inside the transformer can, which reverses the turns ratio
around the center tap of the coil.
If installed, this transformer will cause poor sensitivity. T104 will
not tune properly, and because of insufficient noise, there will be no
squelch action.
The transformer can be checked with an ohmmeter by measuring the
resistance of pins 1 and 3 with respect to the center tap pin 3.
Resistance readings should be as follows:
Pin 1 - 11 Ohms
Pin 2 - Common
Pin 3 - 2 Ohms
Some parts stock shipments may also have included the defective
transformer, and parts stock should be checked as well.
--------------------------------------------------------------------------------------------------------------------
March 25, 1976
HW-202 Bulletin
No:
2 Meter Fm Transceiver HW-202-12
Part No. 417-93 Transistor Installation
The 2N3646 transistor [PN 417-93] used at Q205, Q206 and Q207 are now
being supplied in two different case styles. These transistors are to be
installed as shown in the drawing below:
-----------------Explaination below should explain what the drawing
shows------------
Note the wide space between two of the leads line up this wide space with
the outline of the flat on the circuit board or, in the case of the other
style of transistor, poisiton the flat of the transistor AWAY from the
flat on the circuit board. Then insert the leads into their correct B, C
and E holes.
------------------------------------------------------------------------------------------------------------------
February 14, 1977
HW-202 Bulletin
No:
2 Meter FM Transceiver HW-202-13
Part # 417-803 and # 417-804 Identification
+ + + + Information not available at this time + + + +
------------------------------------------------------------------------------------------------------------------
April 28, 1977
HW-202 Bulletin
No:
2 Meter FM Transceiver HW-202-14
Power Drops Off When Installed in Case
+ + + + Information not available at this time + + + +
-------------------------------------------------------------------------------------------------------------------
June 28, 1977
HW-202 Bulletin
No:
2 Meter FM Transceiver HW-202-15
Knob Removal From Pushbutton Switches
+ + + + Information not available at this time + + + +
-------------------------------------------------------------------------------------------------------------------
September 21, 1977
HW-202 Bulletin
No:
2 Meter FM Transceiver HW-202-16
Unit Inoperative
+ + + + Information not available at this time + + + +
-------------------------------------------------------------------------------------------------------------------
That's all that I show for the HW-202 (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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