			May 31, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-1

	  8.04 MHz Clock on Controller Board Will Not Oscillate

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			May 31, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-2

	      D654 Destroyed When a Linear is Connected

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			June 1, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-3

	                   Blue Book Correction - Alignment

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			June 13, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-4

	    Receiver IF Breaks Into Oscillation After Transmission

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			June 13, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-5

	                     Low or No Output From RF Board

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			June 13, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-6

	  S-Meter Rises Over Half Scale When IF Shift Control Is 
                                                             Rotated

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			June 17, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-7

	                   Blue Book Schematic Correction

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			June 17, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-8

  	                             Blue Book Corrections

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			July 25, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-9

	             RF Circuit Board Schematic Correction

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			August 29, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-10

	     Blue Book Audio Circuit Board Schematic Correction
                                                                  C915

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			October 31, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-11
	
	     Blue Book Corrections - Power Amplifier Schematic

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			November 30, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-12

	                                      Distortion In Audio

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			December 19, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-13

	                                  Output Signal Distorted

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			December 19, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-14

	                   Low Transmitter IF Signal to IF Amplifier

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			December 19, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-15	

	                       IF Amplifier Breaking into Oscillation

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			December 19, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-16

	        Dynamic Range of Audio Amplifier Compressed     

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			December 19, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-17

	                                            BFO Drifting

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			December 19, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-18

	                             Narrow CW Transmit Offset

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			December 19, 1983
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-19

	                               Low Output from High VCO

+ + + + Information not yet available + + + +
--------------------------------------------------------------------------------------------------------------------
			February 29, 1984
HW-5400							Bulletin
No:
HF Transceiver						HW-5400-20

	          BFO And RIT Oscillators Have Insufficient Range;
	                    RF and IF Performance Improvements

The following changes give greater tuning range to the BFO and RIT
oscillator circuits and improve performance of the RF and IF stages.

BFO Circuit

	BFO Circuit Board:

		Change C811 to 220 pF capacitor [PN 20-120].  This
capacitor
		may have been changed to a 180 pF [PN 21-746] per
Bulletin
		HW-5400-17, or it may still be the original 120 pF [PN
20-183].

RIT Circuit

	IF Circuit Board:

		Change R1145 from 1800 ohms to 2200 ohms [PN 6-222-12].
		Change R1151 from 1000 ohms to 1500 ohms [PN 6-152-12].

	Controller circuit board:

		Change C703 and C704 from 330 pF to 220 pF [PN 20-120].
		Change C720 back to a 3.2 - 18 pF [PN 31-71] if it has
been
		previously changed, per Bulletin HW-5400-18.

RF Circuits

	RF circuit board:

		Install a ferrite bead [PN 475-16] on the base lead of
Q401 and
		Q402.

	IF circuit board:

		Install a ferrite bead [PN 475-16] on the base lead of
Q1104 
		and Q1105.

	PA circuit board:

		Install a .01 uF capacitor [PN 21-176] between ground and
the 
		lead of R1207 nearest T1202.
------------------------------------------------------------------------------------------------------------------
			March 9, 1984
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-21

		                 Modification Summary

Below is a summary of all HW-5400 modifications, with applicable Bulletin
Nbrs.  They should be installed in each unit serviced; however, some may
already be present.

	Audio Circuit Board

	-- C908, remove and replace with a jumper wire. [HW-5400-12]
	-- C915, remove and discard. [HW-5400-16]
	-- C929, change from .1 uF to 330 pF [PN 21-722]. [HW-5400-14]
	-- R913, change from 33 Kohms to 68 Kohms [PN 6-683-12]
	    [HW-5400-16]

	High VCO Assembly

	-- R367, change from 100 to 33 ohms [PN 6-330-12]. [HW-5400-19]

	BFO Circuit Board

	-- C811, change from 120 pF to 220 pF [PN 20-120]. [HW-5400-20]
	-- C817, change from 7.7 pF to 27 pF [PN 21-6]. [HW-5400-17]
	-- C819, change from 160 pF to .01 uF [PN 21-761]. [HW-5400-17]
	-- C821, change from 7.7 pF to 27 pF [PN 21-6]. [HW-5400-17
	-- L804, change from 22 uH toroid to 10 uH toroid [PN 45-57].
	    [HW-5400-17]

	ALC Circuit Board

	-- D654, change from a 1N5234B [PN 56-58] to a 1N4751 [PN 56-64].
	    [HW-5400-2]

	Controller Circuit Board

	-- C702, should remain the original value [3.2-18 pF] [PN 31-71].
If it was
	    replaced per Bulletin HW-5400-18, reinstall a [PN 31-71].
	-- C703, change from 330 pF to 220 pF [PN 20-120]. [HW-5400-20]
	-- C704, change from 330 pF to 220 pF [PN 20-120], [HW-5400-20]
	-- C701, add a second diode [PN 56-648] * in parallel
[piggyback].
	    [HW-5400-18]
	-- Q701, change from a MPS6521 to a 2N2369 [PN 417-154].
[HW-5400-1]
	-- Q702, change from a MPS6521 to a 2N2369 [PN 417-154].
[HW-5400-1]

	IF Circuit Board

	-- R1145, change from 1800 ohms to 2200 ohms [PN 6-222-12].
	    [HW-5400-20]
	-- R1151, change from 1000 ohms to 1500 ohms [PN 6-152-12].
	    [HW-5400-20]
	-- Q1104, install a ferrite bead [PN 475-16] on the base lead. 
	    [HW-5400-20]
	-- Q1105, install a ferrite bead [PN 475-16] on the base lead.
	    [HW-5400-20]

	Power Amplifier Circuit Board
	
	-- C1206, install a .01 uF capacitor [PN 21-176] between ground
and the 
	    lead of R1207 nearest transformer T1202.  [HW-5400-20]

	RF Circuit Board

	-- Q401, install a ferrite bead [PN 475-16] on the base lead.
	    [HW-5400-20]
	-- Q402, install a ferrite bead [PN 475-16] on the base lead.
	    [HW-5400-20]
------------------------------------------------------------------------------------------------------------------
			May 31, 1984
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-22
	
		             Blue Book Correction
		 Dual Banana Plug Part Numbers

In the HW-5400 Service Data manual [Blue Book], pages 166 and 169, change
the part number of the dual-banana plug from 438-47 to 438-30.
--------------------------------------------------------------------------------------------------------------------
			July 30, 1984
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-23

	           Wrong Size Pressed-in Spacers On Chassis

Some chassis for this unit have incorrect size pressed-in spacers
installed.  The incorrect size spacers are 1/8" too short and are the
wrong thread size; 4-40 instead of 6-32.  However, most of the chassis
have the correct size spacers and those chassis which have incorrect size
spacers, only two or three spacers may be the wrong size.

The pressed-in spacers are used, in most cases, to mount a circuit board
onto the chassis.  If the incorrect size spacers are tight in the
chassis, you may secure the circuit board at these spacers by installing
the following hardware.

	-- Refer to the drawing at the right and install a 4-40 x 3/4"
screw [PN
	    250-312] from the opposite side of chassis through the
spacer.                                    Tighten this screw into the
spacer.

	-- Install a 4-40 nut [PN 252-2] on the end of the 4-4 x 3/4"
screw and                               tighten it down onto the spacer.

	-- Mount the circuit board with another 4-40 nut [PN 252-2].

Install this hardware as needed.
------------------------------------------------------------------------------------------------------------------
			August 10, 1984
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-24

		PN 56-648 Diode No Longer Available

The MV109 varator diodes at D101, D301, D351, D701 and D701b are changed:

		From PN 56-648 to 56-674.

This new diode is an MV209 and has a different case style.  Install it as
at the right. [[Note: shows mounting the flat side with pc board marked
'band']].  Use this new diode when a replacement is needed.
------------------------------------------------------------------------------------------------------------------
			August 10, 1984
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-25

		    Output On 30 And 40 Meters Too High

To reduce the output on the 30 meter and 40 meter bands, install a trap
on the RF circuit board.

Parts Needed	

	Qty	Description		Heath PN
	   1	470 ohm resistor		6-471-12
	   1	15 pF ceramic capacitor	21-707
	   1	22 uH choke		45-631

Installation

-- Connect the 470 ohm resistor, the 15 pF capacitor and the 22uH choke
in series     as shown at the right.  [[Shows one end of 22uH choke
mounted vertically into     hole marked 'A' , the 15pF capacitor soldered
to the free end of the choke.  The     other end of the cap soldered to
the 470 ohm resistor, which in turn is mounted     vertically into hole
on PCB marked 'B'.]]

-- On the RF board, install the RLC network [[Above]] in the two unused
circuit     board holes near D404.  These holes are marker A and B on the
x-ray view at the     right.  Install the choke in hole A.
-------------------------------------------------------------------------------------------------------------------
			August 17, 1984
HW-5400						Bulletin No:
HF SSB Transceiver 				HW-5400-26

			Improved CW Keying

On the RF circuit board, make the following circuit changes.

Parts needed

	QTY	Description		Heath PN

	   2	1200 ohm resistor		6-122-12
	   1	Diode			56-56
	   1	10 uF capacitor		25-864
	   1	.68 uF capacitor		25-922

Procedure

-- On the RF circuit board, remove the 2200 ohm resistor at R415.

-- Remove the 10 uF capacitor at C424.

-- Change the 4.7 uF electrolytic capacitor at C418 to a .68 uF
electrolytic 
    capacitor [PN 25-922]

-- Refer to the drawing at the right and connect the two 1200 ohm
resistors
    [PN 6-122-12] and the [PN 56-56] in series.  The banded end of the
diode
    connects to the end of a 1200 ohm resistor.  [[[diode - resistor -
resistor]]]

--  Install the resistor - diode combination at R415 on the board.  The
free end  of
    the 1200 ohm resistor connects to the base of Q403.  The anode of the
diode
    connects to the collector of Q412.

--  Connect the 10 uF capacitor [PN 25-864] from the junction of the 1200
ohm           resistors to the ground end of R414.

Install these changes only when needed.
-----------------------------------------------------------------------------------------------------------------
			August 24, 1984
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-27

		Unable To Adjust R803 FOr 8.8307 Mhz

On the BFO board, you may find that when you adjust R837 fully clockwise,
the 8.8307 Mhz frequency is still 100 to 200 Hz too high.  In this case,
change:

	R841 from a 47 kilohm resistor to a 10 kilohm resistor [PN
6-103-12].

After this resistor change is made, repeat the BFO alignment from the
beginning.

Make this change only when needed.
----------------------------------------------------------------------------------------------------------------
			September 21, 1984
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-28

	        Color Dot Missing On Band Switch SW401A/B/C

In Factory Service, some of the wafer switches [PN 63-1386] at SW401A/B/C
were found installed backwards because the color dot used as an
orientation mark on each switch was missing.

To correctly install a switch with no color dot, use the circled number
as the orientation mark.  This circled number is on the same side of the
switch as the color dot would normally be.
--------------------------------------------------------------------------------------------------------------------
			January 31, 1985
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-29

		         Intermittent Lockout Of PLL

The [PN 52-193] transformers used at T101, T102, T103 and T104 do not
have enough adjustment range to enable absolute peaking of the RF level
specified in the synthersizer alignment instructions.  Some of these
transformer's cores will be all the way up or all the way down and do not
reach the peaking point.  Since the RF levels are not peaked, this may
cause intermittent PLL problems.

If the unit you're servicing has an intermittent PLL problem, change:

	T101, T102, T103 and T104 from a [PN 52-193] transformer to a [PN

	52-182] transformer.

Change these transformers only when needed.

Future HW-5400 Transceiver kits will have the [PN 52-182] transformers. 
T105 will remain a [PN 52-193] transformer.
--------------------------------------------------------------------------------------------------------------------
			January 31, 1985
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-30

			 IF Oscillation

On the IF board, IF oscillation problems are being created by the [PN
417-172] transistors used Q1104, Q1105 and Q1106.  Each transistor causes
particular symptoms when it oscillates.  The symptoms are:

	Q1104 - Causes upscale meter deflections.

	Q1105 - Meter jumps full scale in the transition period between
transmit
	                and receive.  Also, the AGC is too slow.

	Q1106 - Meter jumps upscale when temperature varies slightly.

To correct, change:

	Q1104, Q1105 and Q1106 from [PN 417-172] transistors to [PN
417-293]
	transistors.

Install these transistors in the units received for service.
--------------------------------------------------------------------------------------------------------------------
			January 31, 1985
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-31

		Won't Meet Overall Receiver Gain Specs

On the audio board, the previous change of R994 and R995 from a 1000 ohm
resistor to a 47 ohm resistor decreased the audio gain, and now the
Transceiver will not meet overall receiver gain specs.  To ensure the
Transceiver meets specs, change:

	R994 and R995 from a 47 ohm resistor to a 1000 ohm resistor
	[PN 6-102-12].

Install the 1000 ohm resistors in all units received for service.

The bulletin supercedes HW-5400-15 in the 1983 book.
--------------------------------------------------------------------------------------------------------------------
			March 15, 1985
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-32

	       Screws Break Off In Pressed-in Spacers On Chassis

On the main and rear chassis, screws may bind in the pressed-in spacers,
causing the screw to break.  This problem has occurred only on the
copper-colored chassis.  To correct the problem, drill out the broken
screw.  If the spacer with the broken screw is used to mount a circuit
board, remove all the board-mounting hardware and move the board aside. 
Drill out the broken screw from the bottom side of the spacer.  Select a
drill bit that fits inside the spacer so that you don't drill the hole
too large to retap for a 6-32 machine screw.  As you drill out the screw,
be sure to keep the metal particles out of the unit.  Retap with a 6-32
tap.

An insert [PN 591-4676] with two self-tapping screws attached is being
put into the present stock of kits.  The customer is instructed to use
the self-tapping screws to retap all threaded studs before starting
chassis assembly.  Future production of kits will have a chassis with
properly threaded spacers.
-------------------------------------------------------------------------------------------------------------------
			March 22, 1985
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-33

	Transmitter Self-Oscillates In Tune Mode With CW Gain
			   Control FCCW

On the IF board, install a 4700 ohm resistor [PN 6-472-12] from the base
of Q1102 to ground.  This can be done on the top of the board by
connecting one resistor lead to the base at R1107 and the other lead to
the grounded end of R1103.

This additional 4700 ohm resistor ensures that Q1101 and Q1102 turn off
completely during transmit.
------------------------------------------------------------------------------------------------------------------
			March 22, 1985
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-34

	Little Or No ALC Cutback In Transmit Power When Operating
	     Into 3 To 1 Impedance Mismatch [150 Ohm Load]

The ALC cutback operation is tested by connecting the transmitter to a
150 ohm load.  The 3 to 1 mismatch should cause the ALC circuitry to
reduce the transmitter output power about 30%.  To improve the ALC
cutback with high mismatches, on the ALC board:

	Remove the 27 kilohm resistor at R659.
-------------------------------------------------------------------------------------------------------------------
			May 31, 1985
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-35

		      Diode Change At D903 And D904

On the audio board, the [PN 56-656] diodes at D903 and D904 are changed
to [PN 56-56] diodes.  The #56-656 diodes are obsolete.
------------------------------------------------------------------------------------------------------------------
			May 31, 1985
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-36

		     Schematic Correction - Blue Book

On the BFO schematic in the HW-5400 Blue Book, P801-2 should go to
P106-1. P802-2 should go to P905-9.  Mark this correction on your yellow
schematic.
-------------------------------------------------------------------------------------------------------------------
			May 31, 1989
HW-5400						Bulletin No:
HF SSB Transceiver				HW-5400-37

		     1983 TEB Book Correction

In the 1983 TEB book, TEB HW-5400-6, page 143, last paragraph, change
"P918" to read "P905, pin 4".
--------------------------------------------------------------------------------------------------------------------
That's all I have listed for the HW-5400 (1983-89).  Enjoy!


73 de Joe  W7LPF/4  [NNN0KUU]
QWCA - SOWP - NCVA - FISTS - RCC
Gordonsville, Va 22942 [Orange Co]


			

