Heathkit Service Bulletins - HG/HL/HM/HN/HO (Complete)
Joseph W Lutz
joelutz at JUNO.COM
Tue Jan 6 00:22:52 EST 1998
February 7, 1973
HG-10B Bulletin No:
VFO HG-10B-1
Hum On 40 Meters
Replace RFC-1, 28uH [PN 45-18] with a 350 uH choke coil, [PN 45-82].
This change will be put into production soon.
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Thats everything I hold up to 1987 that covers the HG-10B VFO.
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April 6, 1984
HL-2200 Bulletin No:
2KW Linear Amplifier HL-2200-1
Interfacing The Linear To Kenwood Exciters
The ALC voltage to Kenwood transceivers and transmitters should not
exceed -8 volts. To ensure the proper voltage to the Kenwood, add:
An 8 volt zener diode [PN 56-621] across the ALC connector on the
back
of the amplifier. Connect the banded end of the diode to the ground lug.
-------------------------------------------------------------------------------------------------------------------
April 26, 1985
HL-2200 Bulletin No:
2KW Linear Amplifier HL-2200-2
T2 Overheats And Fails When Operating On 220 Volt
Line
When the linear amplifier is wired for 220 volt AC line operation, and
the contacts on SW2 [PN 61-45] or a high voltage transformer winding
opens, excessive current will flow through the primary of low voltage
transformer T2 [PN 54-238], causing it to fail. To prevent this failure,
the black-green lead and the black-yellow lead of T2 are lifted and
connected together with a wire nut.
To do this, refer to the drawing at the right and remove the black-green
lead at lug 3 of terminal strip AE (the lead from T2 at grommet AK) and
the black-yellow lead at lug 2 of SW2. Connect these wires together with
a wire nut [PN 432-199].
Make this wiring change on units you receive for service which are wired
for 220 volt AC operation. Let the customer know that this wiring change
has been made. If he wants to operate on 120 volts AC, he'll have to
reconnect these wires as shown in the assembly manual.
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October 25, 1985
HL-2200 Bulletin No:
2KW Linear Amplifier HL-2200-3
PN 21-79 Capacitor At C7 Unavailable
The .001 uF, 6000 volt ceramic capacitor used at C7 is not available from
our vendors. Until an exact replacement capacitor is obtained from other
sources, two 5000 pF, 3000 volt ceramic capacitors [PN 21-116] will be
connected in series at C7. A bulletin will be issued to notify you when
the PN 21-79 capacitors are once again available.
-------------------------------------------------------------------------------------------------------------------
May 30, 1986
HL-2200 Bulletin No:
2KW Linear Amplifier HL-2200-4
Power ON/OFF Switch Fails
Since the introduction of the HL-2200 Linear Amplifier, the failure rate
of the OFF/ON switch [PN 61-45] at SW1 has been high. This switch was ot
rated high enough to handle the surge current at turn on. The switch
needed for this application could not be supplied by our vendors. To
prevent switch failure, a modification was made to add a high-current
relay in the primary circuit and control the relay with the Power switch.
The Relay Modification Kit [PN 830-94] is available from Heath Parts
Replacement.
The Relay Modification Kits should be installed in all HL-2200s wired for
120 VAC operation. The Power switch rating is not exceeded when wired
for 220 VAC operation.
-----------------------------------------------------------------------------------------------------------------
May 30, 1986
HL-2200 Bulletin No:
2KW Linear Amplifier HL-2200-5
Standby Switch Operates Backwards
When the Standby switch, SW5, is set to the "IN" position, the amplifier
should be on; in the "OUT" position, the amplifier is off. The Standby
switch currently used in the HL-2200 and stocked in Heath Parts
Replacement is a rocker switch; the original switch was a toggle switch.
In all HL-2200 Amplifiers using the rocker switch and wired according to
the manual, Standby switch SW5 operates backwards. To correct, move the
wire from lug 1 of SW5 to lug 5.
--------------------------------------------------------------------------------------------------------------------
December 23, 1986
HL-2200 Bulletin No:
2KW Linear Amplifier HL-2200-6
L3 Mounting Clip Won't Fit Hole In Coil Shield Panel
The 80 meter input coil [PN 40-1012] at L3 now supplied by our vendor has
a coil clip that is too large in diameter to fit the mounting hold in the
coil shield panel. The coil clip on the new coil is .417" in diameter;
the old clip is .406" in diameter. This difference is less than 1/64 of
an inch. The .406" diameter clip is no longer being manufactured.
The new coil can be installed in either of two ways:
1) Remove the coil clip from the old coil being replaced and use this
clip to replace
the clip on the new coil. The old and new coils have the samne
diameter coil
form.
2) If the old clip isn't available, enlarge the mounting hole in the
coil shield panel
about 1/64" larger in diameter.
When the new [PN 40-1012] coils are placed in Parts Replacement stock,
customers who order the new coil will also be sent an instruction sheet
[PN 597-4650] to tell them to use the clip from the old coil or to
enlarge the mounting hole.
--------------------------------------------------------------------------------------------------------------------
January 16, 1987
HL-2200 Bulletin No:
2KW Linear Amplifier HL-2200-7
ICOM Antenna Relay Contacts Fails When Connected
To Antenna Relay Jack On Linear Amplifier
The 120 VDC at the Linear Amplifier antenna jack exceeds the 24 VDC
maximum rating of the antenna relay contacts in the ICOM transmitter.
This excess voltage causes the relay contacts in the ICOM transmitter to
weld together. To prevent this, conect the ICOM transmitter to the
Linear Amplifier using a 12 VDC relay
A relay box for this purpose is available from ICOM America, Inc.
--------------------------------------------------------------------------------------------------------------------
February 6, 1987
HL-2200 Bulletin No:
2KW Linear Amplifier HL-2200-8
Voltage Across Modification Relay Too High
When the PN 890-94 Relay Modification Kit is installed and the Linear
Amplifier is wired for 220 VAC operation, the voltage across the relay is
about 200 VAC; the relay is rated at 120 VAC. To reduce the AC voltage,
change:
Two 1500 ohm resistors to two 4700 ohm resistors [PN 3-21-7].
The two 4700 ohm resistors are connected in parallel for a total
resistance of 2350 ohms. Heath Parts Replacement stock of [PN 890-94]
Modification Kits are being reworked.
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Thats everything I hold up to 1987 that covers the HL-2200 2KW Linear
Amplifier.
-------------------------------------------------------------------------------------------------------------------
January 27, 1984
HM-9 Bulletin No:
QRP Wattmeter HM-9-1
Update for Manual #595-2979
R1, R8, and
M1
R1 has been changed
from: #6-4991-12, 4990 ohms, 1%
to: #6-5231-12, 5230 ohms, 1%
And,
from: #6-6341-12, 6340 ohms, 1%
to: #6-6651-12, 6650 ohms, 1%
R8 has been changed
from: #6-2872-12, 28.7 Kohms, 1%
to: #6-2742-12, 27.4 Kohms, 1%
The meter [M1] has been changed from: #407-762
to: #407-767
Change the manual to reflect these updates on the following pages:
Page 6,
Page 8,
Page 11, left and right columns,
Illustration Booklet, Page 5, R and C Chart on the schematic.
-----------------------------------------------------------------------------------------------------------------
Thats everything I hold up to 1987 that covers the HM-9 QRP Wattmeter.
-----------------------------------------------------------------------------------------------------------------
August 14, 1973
HM-102 Bulletin No:
Watt Meter/SWR Bridge HM-102-1
Possible Shorts Due To Mounting Hardware
The circuit board mounting bolt near R4 -[100K] is extremely close to the
adjacent foil. There is a very good possibility this foil could be
accidentally grounded.
By eliminating the lockwasher and substituting the G-32X1/4" flat head
bolt with a 6-32 X 1/4" round head bolt, [PN 250-31], the problem is
eliminated.
--------------------------------------------------------------------------------------------------------------------
December 23, 1974
HM-102 Bulletin No:
Watt Meter/SWR Bridge HM-102-2
Service Notes
Problems originate because a 50 ohm load is not used for calibration;
even though the kit manual says to use a 50 ohm load, customers use
antennas and even light bulbs. A clue that this is what is being done
wrong is an inablility to null during SWR adjustments. Another clue is
abnormally high power output readings.
If a customer cannot null during SWR adjustment, and he is using ther
proper load, suggest replacing the toroid coil and D-1 through D-3 which
seems to be the magic cure-all for 90% of all the problems encountered
with this unit.
C-4 has been some problem, but this capacitor has been changed to a husky
one [PN 31-57]. The watt meter portion of the unit will not adjust
properly until the SWR balance has been done properly and a good null is
obtained. The indication here is R-6 not adjusting properly. Again, the
toroid coil and D-1 through D-3 is suspect.
Some customers will ask about use of 75 ohm lines. The SWR will be
higher, but collar readings will be within specs. It can be recalibrated
and used with a reasonable degree of accuracy.
A common complaint is the high and low power readings not agreeing.
Explain to the customer the specifications on the meter accuracy which is
plus or minus 10% of full scale.
--------------------------------------------------------------------------------------------------------------------
March 7, 1980
HM-102 Bulletin No:
Watt Meter/SWR Bridge HM-102-3
C4 Destroyed
++++Information not yet available++++
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Thats everything I hold up to 1987 that covers the HM-102 Watt Meter/SWR
Bridge.
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March 2, 1973
HM-2102 Bulletin No:
VHF Watt Meter HM-2102-1
Calibration Problems
Reports have been received of the inability customers are having in
calibrating HM-2102 on watt meter readings. This can be cured by
scraping the area around the hold on the ground foil where the small
spacer fits, when mounting the long bracket. See detail 3B page 7 of the
manual. A good ground connection will make calibrating power readings no
problem.
--------------------------------------------------------------------------------------------------------------------
August 10, 1973
HM-2102 Bulletin No:
VHF Watt Meter HM-2102-2
Inaccurate SWR Null
The shell of the input coax connector is in close proximity to the brass
eyelet come in contact, the SWR cannot be accurately nulled. This is a
problem area worthy of checking before any alignment is accomplished.
Repositioning circuit board on angle mounting brackets will eliminate
this problem.
--------------------------------------------------------------------------------------------------------------------
September 17, 1974
HM-2102 Bulletin No:
VHF Watt Meter HM-2102-3
Calibration Circuit Correction
Perform the modification as shown in the above Pictorial.
(((Pictorial shows foil side of board. Instructions state to: Place C-2A
close to foil side of board, solder to leads of C-2 and foil pads, then
cut off excess lead length. It also lists the following values:
2 Meters
6 Meters
C-2 - 15pF - PN 20-118
C-2 - 15pF - PN 20-118
C-2A - 1pF - PN 28-2
C-2A - 2.2pF - PN 28-1)))
This modification will correct for the internal calibration problem and
make the unit more accurate with respect to actual power input. This
modification should only be done on units which have a glass epoxy board.
Capacitor C2 is increased to 16 pF for 2 meters and 17 pF for 6 meters.
New 16 pF and 17 pF capacitors will be in the line in the future and this
modification may be used until the new capacitors are available.
--------------------------------------------------------------------------------------------------------------------
February 11, 1976
HM-2102 Bulletin No:
VHF Wattmeter HM-2102-4
Separate High Power Calibration
An article in HAM RADIO magazine [February 1976] described a modification
to permit separate calibration of the high power scale.
The article is reprinted below for information only; it is NOT a
production change or service modification.
HIGH POWER CALIBRATION FOR THE HEATH HM2102 VHF WATTMETER
The great crowds of two-meter fm enthusiasts will no doubt provide the
Heath Company with a continuing market for their HM2102 vhf watt meter.
This dandy piece of equipment provides two switch selectable power ranges
of 25 and 250 watts full scale, in the 50 to 160 MHz range, and also
includes a built-in swr bridge.
In checking out my wattmeter I found that everything worked fine with
the exception of a noticeable discrepancy in the accuracy of the high
power [250 watt] range. Checking further, I found that the problem was
due to the fact that R8, a 68k resistor which is used as a meter
multiplier in the 250 watt range, was out of tolerance. The problem
could have been cured by replacing R8 with a new resistor, but it
occurred to me that even greater accuracy could be obtained by replacing
R8 with a variable 100k resistor to allow separate calibration of the
high power range.
This modification is easily done and works out very nicely. The
small trim pot may be supported by using short pieces of solid hookup
wire inserted in the PC board holes formerly occupied by R8. The
adjusting slot should bace upward in the same direction as potentiometer
R6. A hole in the cover plate allows access to R8 when the cover is in
place. This access hole can be labeled high for high power adjust, and
the hole already in the plate for R6 can be labeled "low".
The original calibration procedure calls for adjusting R6, a 50k pot,
in the low power position, which also affects the high power calibration.
With the addition of a 100k pot for resistor R8, the new calibration
procedure is as follows:
1. Using a known power source in the 10 to 25 watt range, and/or
comparing with another wattmeter of known accuracy, adjust R6 for the
correct meter indication in the 25 watt range.
2. Switch to the 250 watt range, and again using a transmiter
with known output, and/or a comparison wattmeter, adjust R8 for correct
meter indication.
Both ranges are now individually calibrated. Any further adjustment
of R6 will require readjustment of R8.
-------------------------------------------------------------------------------------------------------------------
June 5, 1978
HM-2102 Bulletin No:
VHF Wattmeter HM-2102-5
Calibration Problem
If a calibration problem exists, such as power calibration and SWR null,
change:
C3 from 7.7 pF to 1.5 pF [PN 28-4] and
R7 from 10k ohm to 5.6k ohm [PN 1-113]
-------------------------------------------------------------------------------------------------------------------
January 27, 1982
HM-2102 Bulletin No:
VHF Wattmeter HM-2102-6
SWR Cannot Be Nulled
++++Information not available at this time++++
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Thats everything I hold up to 1987 that covers the HM-2102 VHF Wattmeter.
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May 16, 1980
HM-2140 Bulletin No:
HF Dual Wattmeter HM-2140-1
Inoperative
++++Information not available at this time++++
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August 13, 1980
HM-2140 Bulletin No:
HF Dual Wattmeter HM-2140-2
Battery Meter Pegs And Unit Will Not Null
++++Information not available at this time++++
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January 27, 1984
HM-2140 Bulletin No:
HF Dual Wattmeter HM-2140-3
PEP Readings Inaccurate
Make the following changes to the remote sensor and main unit. Recheck
the calibration after installing these changes. New production will have
these changes included.
Remote Sensor [PN 100-1749]: Change C106 and C107 to .0027 uF [PN
27-141].
Do not disturb any control settings after making the change. Be
sure
to reseal the sensor using a service sticker.
Main Unit: Change: C17 to .022 uF [PN 27-128]
C18 to .033 uF [PN 27-138]
Note: The only accurate method of checking PEP calibration is by using a
two-tone test generator. The FCC standard tones for the two tone test
are 400 Hz and 1800 Hz. A whistle represents only one tone and will give
the same output as a steady carrier [CW] signal. Voice modulation may
give a slightly different reading since the voice is composed of many
tones. The PEP readings should be very close if the AVERAGE power
readings are close. [PEP does not have an accuracy specification.]
--------------------------------------------------------------------------------------------------------------------Thats
everything I hold up to 1987 that covers the HM-2140 HF Dual Wattmeter.
--------------------------------------------------------------------------------------------------------------------
December 23, 1974
HN-31 Bulletin No:
Dummy Load HN-31-1
Service Notes
Over the last two or three years, we have had problems with resistors in
the HN-31 dummy load. They are not sealed properly, becoming soaked in
oil and increasing in value. Even though the customer is using the
proper load, you will have calibration problems due to the change in
resistance.
All stores should check their HN-31 Dummy Loads from time to time, for
proper value.
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Thats everything I hold up to 1987 that covers the HN-31 Dummy Load
---------------------------------------------------------------------------------------------------------------
January 13, 1975
HO-10 Bulletin No:
Monitor Scope HO-10-1
"HOT"
Chassis
Some transformers [PN 54-130] have been found to break down after about
five hours of use. The primary shorts to the high voltage secondary,
raising the chassis approximately 1000V above the line voltage.
If a new power transformer has been installed, be sure to let the unit
operate for a while before returning it to the customer.
The vendor has been notified, and corrections will be made in replacement
stock.
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October 21, 1980
HO-10 Bulletin No:
Monitor Scope HO-10-2
Replacing The Power Transformer
++++Information not available at this time++++
--------------------------------------------------------------------------------------------------------------------
December 9, 1981
HO-10 Bulletin No:
Monitor Scope HO-10-3
Replacing The Power Transformer
((Supercedes Bulletin HO-10-2))
++++Information not available at this time++++
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Thats everything I hold up to 1987 that covers the HO-10 Monitor Scope
-------------------------------------------------------------------------------------------------------------------
October 18, 1985
HO-5404 Bulletin No:
Station Monitor HO-5404-1
Low Intensity
Low intensity can be cause by arcing between the body of R16, 470 kilohm
resistor [PN 6-474-1], and front panel chassis. On each unit received
for service, position the body of R16 at least 1/16" away from the
chassis and controls.
------------------------------------------------------------------------------------------------------------------
January 16, 1987
HO-5404 Bulletin No:
Station Monitor HO-5404-2
CRT Mounting Spacers Change
To complete a production run of HO-5404 kits, the two 6-32 x 1-3/4" round
spacers [PN 255-708] used to mount the CRT were replaced with four 6-32 x
7/8" hex spacers [PN 255-724] and two 6-32 x 3/4" setscrews [PN
250-1158]. Two of the hex spacers are joined together with the setscrew
to make the 1-3/4" spacer needed as shown is the drawing at the right.
Manual insert [PN 591-5100] tells the customer how to install these
spacers.
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Thats everything I hold up to 1987 that covers the HO-5404-1 Station
Monitor.
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September 20, 1985
HOA-5404-1 Bulletin No:
Pan Adaptor Module HOA-5404-1-1
Not Recommended For Use With HW-9 And HW-99 Transceivers
The HOA-5404-1 Pan Adaptor Module is not compatible with the Heath HW-9
and HW-99 Transceivers. When connected to these transceivers, the sweep
from the HO-5404 Station Monitor could be heard in the receiver audio.
The sweep noise was heard on all bands. Engineering considers the noise
levels objectionable and does not recommend the Pan Adaptor Module be
used with these two transceivers.
-------------------------------------------------------------------------------------------------------------------
Thats everything I hold up to 1987 that covers the HOA-5404-1 Pan Adaptor
Module
-------------------------------------------------------------------------------------------------------------------
Okay - got this caught up to 1987 - it's after midnight and should get
to bed. There is more to come. Hope everyone had a Great Holiday
Season. Ciao!
73 de Joe W7LPF/4 [NNN0KUU]
QWCA - SOWP - NCVA - FISTS - RCC
Gordonsville, Va 22942 [Orange Co]
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