Heathkit Service Bulletins - HW-100 (Complete 66-89)
Joseph W Lutz
joelutz at JUNO.COM
Sat Mar 21 23:11:53 EST 1998
November 1, 1967
HW-100 Bulletin No:
SSB Transceiver HW-100-1D
Improper tuning
Delete: [2] 26-109 [2] Variable Capacitor, 2 Sect. P.C. Mtg
Add: [2] 27-122 [2] Variable Capacitor, 2 Sect. P.C. Mtg
Delete: [4] 85-131-1 [1] PC Board, RF Driver Mixer [85-131
Screened 605-1225]
Add: [4] 85-131-2 [1] PC Board, RF Driver Mixer [85-131 Screened
605-1616]
Reason for change: To correct tuning trouble.
------------------------------------------------------------------------------------------------------------------
September 14, 1972
HW-100 Bulletin No:
SSB Transceiver HW-100-1
Repeated Heterdodyne Oscillator Tube Failure
Inadequate USB-LSB
Frequency Shift
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 10000 ohm [PN 1-9].
------------------------------------------------------------------------------------------------------------------
September 14, 1972
HW-100 Bulletin No:
SSB Transceiver HW-100-2
Diode Leakage in the SB-100/SB-101/HW-100
The silcon diodes used in the SB-100 and SB-101 are standard power diodes
rated at 500V PIV and 750ma. For each condition described, the diodes
should be replaced with an equal value top maintain proper operation.
1. Diodes D902 and D903, when leaky, will have an effect on ALC
indication. The ALC indication will be normal for the first half hour to
an hour. Then the meter indication will start dropping off until there
is very little indication.
2. D101, when leaky or defective, will cause slow or no receiver
recovery after transmitting for any period of time.
3. D905, under leaky conditions, will cause very slow receiver recovery
and false meter indications. The meter will kick up scale and slowly
drift down to zero.
4. D201 will result in a decrease in VOX sensitivity to the point where
the VOX circuit will not be activated. It can also result in increasing
VOX delay, causing the relay to stay in the transmit condition.
-------------------------------------------------------------------------------------------------------------------
May 23, 1974
HW-100 Bulletin No:
SSB Transceiver HW-100-3
Alternate Method of Neutralizing the Final Amplifiers
Note: Be sure unit is off and power supply high voltage capacitors are
discharged.
1. Disconnect final plates and screen grid. **
2. Turn unit on.
3. Rotate the band switch to 28.5.
4. Place the VTVM RF probe in the antenna connector.*
5. Set the function switch to tune.
6. Rotate the level control fully clockwise.
7. Adjust the preselector control for a maximum indication on the VTVM.
8. Adjust the final control for a maximum indication on the VTVM, with
the load control set at the 50 ohm position.
9. Using an insulated screwdriver, adjust neutralizing capacitor for a
minimum indication on the VTVM.
10. Readjust the neutralizing capacitor for a minimum indication on the
VTVM.
11. Turn the function switch to the off position.
12. Discharge high voltage power supply capacitors.
13. Reconnect final plates and screen grid.
* VTVM and RF probe will be needed.
**To remove screen voltage in SB-100, HW-100 and HW-101 disconnect R920
[100 ohm resistor] from buss wire between pins of V8 and V9. In the
SB-102 removal of accessory plug is all that's required. To remove high
voltage in SB-100, SB-101 and SB-102 disconnect red wire at lug 4 [in
SB-100 lug 3] of terminal strip BK that goes to grommet BL. In HW-100
and HW-101 disconnect red wire going to lug 1 of RF choke in final cage.
Note: Take adequate steps to eliminate any possible contact with B+ or
B+ shorts to chassis after disconnecting wire and resistor.
--------------------------------------------------------------------------------------------------------------------
May 23, 1974
HW-100 Bulletin No:
SSB Transceiver HW-100-4
SB & HW Series Audio Preamplifier & VOX
Circuit Trouble Shooting
Guide
It is assumed that the basic steps such as making DC voltage measurement,
checking tubes & reviewing the soldering have been completed.
The following information was compiled from the above transceivers in the
80M LSB position. The mike level control was at the 9:00 o'clock
poisition.
AC signal voltages are listed below. These voltages were measured from
the microphone connector through the VOX circuit. All measurements were
made with a VTVM. A microphone or audio generator for .1V @ 1KHZ can be
used as the signal source.
Mike Connector Lug 1
.1VAC
Pin 2 of V1 .02VAC
Pin 6 of V1 10-15VAC
Pin 6 Level Control 10-15VAC
Pin 5 Level Control .5VAC
Pin 9 of V1 .2VAC
Pin 8 of V1 .1 - .3VAC
Center Arm of VOX Sensitivity Control 5-15VAC
Pin 7 of V17 5-10VAC
Pin 6 of V17 40-50VAC
Junction of C211-D201 40-50VAC
Pin 9 of V12 9-15VAC
By tracing the AC signal from stage to stage the point of trouble can be
isolated & steps taken to correct it.
POSSIBLE TROUBLE AREAS
- Check each of the shielded cables for a possible open or poorly
grounded shield.
- Check for continuity through each of the shielded cables.
- Check for a proper ground at the mike control level.
- If the frequency response of the audio stage is not within
specifications check the values & installation of C1, C2, C3 & C9.
- A change in VOX delay after operating for a period of time can be
caused by leakage in diode D201. The other possibility is a change in
value of capacitor C213. Either component could experience a change in
operation characteristics due to heat.
--------------------------------------------------------------------------------------------------------------------
May 23, 1974
HW-100 Bulletin No:
SSB Transceiver HW-100-5
SB & HW Series Instability & Corrective Information
We suggest you check for each of the following possible causes:
1. Intermittent, rosin or cold solder joints.
2. Loose hardware at the tube sockets, terminal strips, circuit boards,
shields and rear panel sockets.
3. Poor lead dress at tube sockets V8 & V9. The component leads must be
short as possible.
4. Check C925 (Final tune capacitor) to be sure it is isolated from the
tuning shaft. This is to prevent RF from traveling on the shaft to the
front panel.
5. Check all edges of the final enclosures for proper grounding to the
main chassis.
6. Check the hardware for the side rails to be sure a good ground is
being provided.
7. Be sure that all the ground clips on the coil cover are making good
contact with the switch shields.
8. Check the soldering of the switch shields to the center pins of tube
sockets V6, V7, V10 & V11.
9. Check the ground leads from the switch board & shields, to be sure
they are going to ground foil & not to the preselector capacitor foil
pods on the RF driver board.
10. Check for broken or shorted pigtails on each of the shielded cables
in the unit.
11. Check RFC801 & L901 for any signs of deterioration or physical
damage, (burn spots). If apparent replace the part.
12. Improper adjustment of the Het. Osc. coils could cause improper
mixing action, resulting in the final operating at a different frequency
appearing as instability.
13. Change driver & final tubes then reneutralize per manual
instructions.
14. Check driver tube shield to be sure that it has a good ground
contact with the socket spring clip.
15. Check for a good ground between the front panel & chassis.
16. Check the SWR of the antenna system at the frequency of opertion.
Should be below 2:1.
17. Check the antenna coax for leakage, poor connectors & broken shield
connections.
18. Is the transmitter properly grounded?
19. Be sure all shields & tube shields are installed.
20. Realign using a properly terminated 50 ohm non-reactive dummy load.
NOTE: This does not include a light bulb.
21. Check for normal Het. Osc. test-point voltage.
22. Check for proper LMO injection voltage 1.0-1.5 VRF.
23. Check for a high AC ripple content in the LV-B+, HV-B+ and bias
voltages from the power supply.
24. Check to be sure that the shafts do not touch each other in the
insulated coupling, and that the set screws do not touch the PA shield.
25. Check to be sure that the PA tune shaft turns the variable capacitor
& is not slipping in the insulated coupling.
--------------------------------------------------------------------------------------------------------------------
December 18, 1974
HW-100 Bulletin No:
SSB Transceiver HW-100-6
Oscillations or Low Drive
Loose boards cause sporatic self oscillations & unstable RF conditions,
particularly at the high [15 & 10 meter] bands. The comb brackets which
have been used are aluminum & could not be soldered. Steel brackets are
now available [PN 204-2096] & should be used whenever encountered in the
field. Both the switch shields & the driver boards should be soldered to
these brackets.
This change helps to increase grid drive as well as increase stability.
--------------------------------------------------------------------------------------------------------------------
November 15, 1976
HW-100 Bulletin No:
SSB Transceiver HW-100-7
Low Receiver Sensitivity
Note: Sensitivity of the unit is worse on the higher frequencies [15] &
[10] meters.
Cure: Diode D907 may be in backwards or banded backwards.
--------------------------------------------------------------------------------------------------------------------
June 5, 1978
HW-100 Bulletin No:
SSB Transceiver HW-100-9
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 [PN 411-124]. IEC brand tubes have
been found defective in several cases, but other brands may also cause
this problem.
-----------------------------------------------------------------------------------------------------------------
June 5, 1978
HW-100 Bulletin No:
SSB Transceiver HW-100-10
Poor AGC Action
Leakage in the 6HS6 [PN 411-247] at V10 and/or V11 has been found to
cause:
- Poor AGC action
- Fast S-Meter decay,
- Poor sensitivity when RF gain control is fully
clockwise.
This usually occurs after warmup of at least an hour. A positive
voltage, usually over 1 volt, will appear at the grid, pin 1 of either
one or both tubes.
Replacement of the tube with the positive voltage corrects the problem.
-----------------------------------------------------------------------------------------------------------------
June 5, 1978
HW-100 Bulletin No:
SSB Transceiver HW-100-11
100 KHZ Calibrator Spurs
Strong signals may occur at other than 100 KHZ points.
Look at the calibrator output [ahead of output diode] with an
oscilloscope. Use high input gain and a slow sweep speed. If the upper
portion of the sine-wave signal appears choppy or uneven, the Y201
crystal may be at fault.
After installation of a new crystal [PN 404-43], recheck with an
oscilloscope.
----------------------------------------------------------------------------------------------------------------
August 3, 1978
HW-100 Bulletin No:
SSB Transceiver HW-100-12
Receiver Recovery Slow
************Bulletin Obsolete--------Refer to Bulletin No:
HW-100-20******************
------------------------------------------------------------------------------------------------------------------
July 24, 1978
HW-100 Bulletin No:
SSB Transceiver HW-100-13
Poor Preselector Tracking
This problem is more noticeable on the 10-meter band. It may be caused
by the drive belt slipping or by one of the variable capacitors not
turning due to excessive friction inits bearings.
Check the belt for being loose or worn and replace as needed. Lubricate
the bearing of the variable capacitors.
If lubricating the capacitor bearings does not allow the rotor to turn
freely, replace the capacitor [PN 26-122].
--------------------------------------------------------------------------------------------------------------------
July 24, 1978
HW-100 Bulletin No:
SSB Transceiver HW-100-14
Carrier Nulls With 1C14 Trimmer Plates Completely Meshed
If C14 nulls the carrier with its plates fully meshed toward V2 [to the
right], relocate C18, 12pf capacitor, to the other section of the null
trimmer [C14].
--------------------------------------------------------------------------------------------------------------------
August 3, 1978
HW-100 Bulletin No:
SSB Transceiver HW-100-15
Relays Chatter In VOX Mode
This may occur when the VOX gain is in the near-full CW position with the
MIC level advanced past the 12 o'clock position. Also, the unit will not
return to receive when the operator stops talking.
Check the tube at V1. A "GE" tube will tend to oscillate, thus causing
the above problem. Other 6EA8 tube brands should operate properly at V1.
--------------------------------------------------------------------------------------------------------------------
August 3, 1978
HW-100 Bulletin No:
SSB Transceiver HW-100-16
Loading Capacitor Turns As Plate Capacitor Is Rotated
This problem can be caused by:
- Insuffiecent friction in the loading capacitor or;
- Excessive friction between the plate and load tuning shafts.
If the problem persists after freeing and lubricating the shafts, install
a rubber grommet [PN 73-3] on the loading capacitor shaft between the
pulley and the RF cage. Apply slight pressure to the grommet as the
pulley set-screw is tighted. This will add enough friction to keep the
loading capacitor still while tuning the plate control. Use only as
needed.
---------------------------------------------------------------------------------------------------------------
August 22, 1978
HW-100 Bulletin No:
SSB Transceiver HW-100-17
S-Meter Drift
If the S meter drops below zero and pins after 1/2 hour of operation,
there may be leakage in one or more of the following tubes: V3, V4, V10
or V11. New RCA tubes may exhibit the same problem. The following
procedure will aid in finding the leaky tube:
1. Disconnect R415 to isolate V3 and V4 from the AGC line.
Monitor the control grid at P1 of V3 for several minutes. If the voltage
drifts in the positive [+] direction, V3 or V4 is leaky. Proceed to step
2. If the voltage remains stable, go to step 5.
2. Remove the white/blue wire from pin 2 of T102 and repeat the
test. This will isolate V4 from V3. If the voltage still drifts, V3 is
at fault.
3. To verify, reconnect the white/blue wire and then disconnect
R101. Monitor the voltage at pin 1 of V4. The voltage should remain
stable.
4. Reconnect R415 and R101.
5. Disconnect R408 and check the voltage at pin 1 of V10. If
voltage drifts, replace V10. If the voltage is stable, replace V11.
6. Reconnect R415 and R408.
Straight substitution with new tubes may not work if more than one tube
is causing the problem, since even a small leakage can cause the drift.
When you replace a tube, check for stable voltage at its control grid.
Replace with the tube which gives most stable voltage.
-----------------------------------------------------------------------------------------------------------------
August 21, 1978
HW-100 Bulletin No:
SSB Transceiver HW-100-18
ALC Meter Reads Below Zero
If the ALC meter reads below zero on SSB transmit and low on voice peaks,
perform the following:
- Install a 2K ohm resistor [PN 1-90] between lug 1 of relay 1
and the center lug of the S meter zero adjust control.
For fussy customers, a 10K ohm trim control [PN 10-312] may be used for
exact zeroing on both transmit and receive.
-----------------------------------------------------------------------------------------------------------------
September 26, 1978
HW-100 Bulletin No:
SSB Transceiver HW-100-19
Poor IF Sensitivity
Check C101. It may have inadvertently been wired to point 2. It should
be wired to point 15. It is an "easy-to-overlook" wiring error that
would cause the transceiver to have low if sensitivity which would result
in poor receiver sensitivity and low power output.
--------------------------------------------------------------------------------------------------------------------
October 10, 1978
HW-100 Bulletin No:
SSB Transceiver HW-100-20
Receiver Recovery Slow
This is an improved method of grounding the PA tube screens in receive
mode. The screens will now be grounded through the unused contacts of
RL1, independent of the action of RL2.
Complete the following wiring changes:
1. Disconnect the WHT-ORG-ORG lead from RL2, lug 7 and reconnect
it to RL1, lug 10.
2. Connect RL1, lug 2 to ground.
3. Connect a wire to RL1, lug 6 to RL2, lug 7.
This Bulletin will supersede TEB-100-12 dated August 3, 1978.
At RL1, the PA screen connection [Lug 10] will always break from the +300
volt supply condition [Lug 6] before the screens are grounded by lug 2 in
receive condition [de-energized relay]. This eliminates the possibility
of the +300 volt supply momentarily being shorted to ground during
transition from transmit to receive.
This midification is NOT/NOT for the SB-100, SB-101 or SB-102
transceivers.
----------------------------------------------------------------------------------------------------------------
April 25, 1979
HW-100 Bulletin No:
SSB Transceiver HW-100-21
Low Power Output; Poor Vox Sensitivity
It has been determinded that Sylvania, RCA and Westinghouse brand tubes
do not function properly at locations V3 and V4.
The brands found to work at these locations are: EL-MENCO, IEC, General
Electric and Realistic.
Westinghouse tubes at other locations throught the unit may cause low
power output and VOX problems. It is suggested not to use Westinghouse
tubes at all.
-------------------------------------------------------------------------------------------------------------------
May 7, 1979
HW-100 Bulletin No:
SSB Transceiver HW-100-22
Drive Slips or Doesn't Turn At All
The following is a modification of the HW-100 dial and VFO drive [PN
467-1].
Replacement parts are no longer available.
The customer who orders a PN 467-1 will receive the PN 969-48 parts pack
and instruction sheet [PN 597-2065].
Parts required:
The following parts may be obtained by ordering parts pack [PN
969-48] which consists of:
1 - Vernier drive [PN 100-1041]
1 - Knob [PN 462-193]
2 - Knob setscrews [PN 250-93]
8 - #3 Lock washers [PN 254-7]
8 - #3 Nuts [PN 252-1]
2 - #6 Screws [PN 250-56]
1 - #6 X 3/8 Screw [PN 250-162]
Procedure:
A] Remove tuning knob and vernier drive assembly.
B] Remove VFO and dial.
C] Remove dial and hardward from VFO tuning shaft.
D] Modify shaft and dial.
E] Modify front panel. ((Tap holes for 6/32 machine screws, and enlarge
hole to 1-1/8" using a chassis punch))
F] Remount VFO [Do not tighten mounting nuts] with dial installed on
modified shaft. Dial must extend 1/4" in front of mounting plate.
G] Install vernier drive [PN 100-1041] to modified front panel with two
6/32 X 1/4" machine screws [PN 250-56].
H] Align VFO into drive and tighten VFO mounting hardware.
I] Tighten setscrews on new vernier drive.
J] Install new knob [PN 462-193] with setscrews [PN 250-93].
K] Align VFO dial.
Note: modified drive will turn faster than original.
--------------------------------------------------------------------------------------------------------------------
May 7, 1979
HW-100 Bulletin No:
SSB Transceiver HW-100-23
Driver Preselector Won't Peak For Full Output At 7.0 MHZ
When aligned the 40-Meter driver grid/plate coils at 7.2 MHZ with the
driver preselector control at the 12 o'clock position, there may not be
enough grid drive for full output when tuned to 7.0 MHZ. The preselector
will be full CCW without peaking.
To correct, realign the 40-Meter driver grid/plate coils with the VFO set
at 7.2 MHZ and the driver preselector control set to the one o'clock
position.
At 7.3 MHZ, the driver preselector will still peak before reaching full
CW.
-------------------------------------------------------------------------------------------------------------------- January
21, 1980
HW-100 Bulletin No:
SSB Transceiver HW-100-24
Low Grid Drive on Certain Portions of One or More Bands
+ + + + Information not available at this time + + + +
-------------------------------------------------------------------------------------------------------------------
December 17, 1980
HW-100 Bulletin No:
SSB Transceiver HW-100-25
VOX Oscillation
+ + + + Information not available at this time + + + +
------------------------------------------------------------------------------------------------------------------
Okay, thats all I have/show for the HW-100 up to 1989. Enjoy!
------------------------------------------------------------------------------------------------------------------
73 de Joe W7LPF/4 [NNN0KUU]
QWCA - SOWP - NCVA - FISTS - RCC
Gordonsville, Va 22942 [Orange Co]
This finishes what I have on HW-100. Ciao!
73 de JOE- - - - - - - - - - -W7LPF/4 (NNN0KUU)- - - - - - - - - - - - -
- -QWCA - NCVA - SOWP - FISTSGordonsville, Va 22942 (Orange
County)Looking for: Heathkit HR/HX-20, MR/MT-1,
Central Electronics 100V or 200V- - - - - - - - - - - - - - - - - - - - -
- - - - - - - - - - - - -
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