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KNWD440.TXT
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1993-07-17
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SB-951
TS-940S ERRATIC DISPLAY 01/20/89
Intermittent control or display problems that are difficult
to correct with the reset procedure may be caused by a
faulty ROM socket. The socket should be checked to insure
that it makes good electrical contact with each pin of the
ROM. If it is found to be intermittent, remove the socket
and solder the ROM directly to the board. It should be
noted that units between serial numbers 701XXXX to 811XXXX
and from 903XXXX to 909XXXX are not likely to have this
failure. In addition, units with a serial number of 909XXXX
and above do not incorporate a socket.
CAUTION
Removing the socket requires good soldering skills. The ROM
is mounted on the Digital A unit and is designated as IC2.
The board, being double sided, has solder connections on
both component and foil sides. When the socket is removed,
it is very important to insure that each pin is completely
solder free. Having to pry up on the socket means that it
is not completely desoldered and will cause the circuit
foils to tear.
When performing any work on the Digital A board, CMOS
handling techniques must be observed. Such techniques
include using a grounded or isolated soldering tip, avoid
touching the pins of IC chips with your fingers, and ground
yourself with a wrist ground strap.
To remove the socket:
1. Disconnect the power cord and antenna coax.
2. Remove the top and bottom covers from the transceiver.
3. Remove the 2 flat head screws from each side of the
front panel chassis.
4. Loosen the round head screw on each side of the front
panel chassis.
5. Carefully rotate the front panel forward. It will be
necessary to unplug the VS-1 cable from the transceiver.
6. Remove the 4 screws from the speaker mount.
7. Carefully pull up on the mount and rotate it toward the
front panel. Swing the mount toward the right side of
the transceiver and allow it to rest on the Digital B
unit shield.
8. Remove the 8 screws from the Digital A unit shield
plate.
9. Lift the plate and rotate it to the left side of the
transceiver.
10. While avoiding contact with the pins, remove the ROM
(IC2) and set it aside on anti-static foam.
11. Remove the 6 screws that mount the Digital A board.
Rotate the board toward the front panel to expose the
bottom side of the board.
12. Carefully desolder the socket and remove it from the
board. Do not pry up on the socket. If it does not
easily pull off the board, the top foils are still
soldered to the socket.
13. Install the ROM in the board and solder it in place.
14. Assemble the transceiver by reversing steps 1 - 11. Do
not pinch the power switch cables between the front
panel and the body of the transceiver.
Time required for this modification is 1.5 hrs or less. (C)
011189TKC
Kenwood U.S.A.
Service Bulletin Extract
Amateur Radio
Number: SB950
Subj: TS-440S Case Screws binding in the heat sink.
Date: 01/20/89
Occassionally a case screw that fastens to the heat sink of the TS-440S
will cross thread or bind when it is being inserted or removed.
Binding may be caused by tooling marks on the screw or by burrs on the
tapped threads in the heat sink. When a screw starts to bind, DO NOT
TRY TO FORCE IT! as this may cause the head to shear off. If the screw
is being removed and it starts to bind, return the transceiver to
KENWOOD. Do not make attempts to remove the screw. In addition, if a
transceiver is being brought to you with a scrw sheared off, return
the unit to KENWOOD. Do not attempt to drill out the screw.
If a screw starts to bind when it is being installed, carefully back it
out. Inspect the screw for marks or burrs and replace it if it is
questionable. Since the threads in the heat sink may be causing the
screw to bind, they should be cleaned by running a 3 x 0.5 mm tap into
each hole. The tap is inexpensive and can be obtained at may of the
larger hardware stores.
To avoid cross threading, make sure the covers are properly aligned when
they are being installed. Proper alignment means that there is a clear
path for the screw to turn into the heat sink. This assures that the
screw does not rub against the case and result in it turning into the
heat sink at an angle.
SB-949
TS-440S PROTECTING Q33 01/20/89
If pin 7 (RL) of the remote connector is accidently
connected to ground, current from the 14 volt line (14L)
will damage transistor Q33 on the IF unit. This will prevent
the radio from transmitting. To protect Q33, a 4.7 ohm
resistor should be installed in series with the RL line on
the foil side of the IF board. In the event that pin 7 is
connected to ground, the resistor will open, but the
transceiver will still be capable of transmitting.
REQUIRED PART:
4.7 OHM, 1/6 WATT RESISTOR ........ RD14CB2C4R7J
1. Disconnect the power supply and antenna from the
transceiver.
2. Using a #2 Phillips screw driver, remove the 9 screws
from the top cover of the transceiver. Remove the cover
and unplug the speaker wire.
3. Locate connector 19 on the IF unit.
4. Using a #1 Phillips screw driver, remove the 7 screws
that secure the IF unit to the chassis of the
transceiver.
5. Pull the board up and rotate it towards the front of the
transceiver to expose the foil side of the board.
6. On the foil side of the board, locate the trace that is
connected to pin 3 (brown wire) of connector 19.
7. Using a craft knife, cut the trace comming from pin
three so as to open the foil trace.
8. Solder the 4.7 ohm resistor across the now open trace
(i.e. in series with the trace).
9. Assemble the transceiver by reversing steps 1 - 5.
This is an optional change that may not be covered under
warranty.
Time required for this modification is 0.5 hrs or less.
(C) 112188TKC
SB-948
TS-440S NOTCH FILTER LOW FREQUENCY IMPROVEMENTS 01/20/89
The low frequency attenuation characteristics of the notch
filter can be improved by reducing the input level to the
notch filter chip (IC1). To compensate for the loss of input
level, the amount of negative feedback to the audio
amplifier (IC7) will need to be reduced. This modification
is already incorporated in all models beginning with serial
number 704XXXX.
REQUIRED PARTS:
120K OHM, 1/6 WATT RESISTOR ........ RD14CB2C124J
390 OHM, 1/6 WATT RESISTOR ........ RD14CB2C391J
1. Disconnect the power supply and antenna.
2. Using a #2 Phillips screw driver, remove the 9 screws
from the top cover. Remove the top cover from the
transceiver and unplug the speaker wire.
3. Locate resistors R86 and R229 on the component side of
the IF board (Figure 1).
4. Using a #1 Phillips screw driver, remove the 7 screws
that secure the IF unit to the chassis of the
transceiver.
5. Pull the board up and rotate it towards the front of the
transceiver to expose the foil side of the board.
6. Desolder and remove both resistors from the board.
7. Install and solder a 102K ohm resistor in place of R86.
8. Install and solder a 390 ohm resistor in place of R229.
9. Assemble the transceiver by reversing steps 1 - 5.
This is an optional change that may not be performed under
warranty.
Time required for this modification is 0.5 hrs or less.
(C) 110788TKC
SB-947
TS-440S OPERATION WITH THE MC-85 01/20/89
With some TS-440S transceivers, insufficient modulation may
occur when the MC-85 compression switch is turned on. This
may be caused by too much of a voltage drop across resistor
R172 on the IF unit of the transceiver . If this is found to
be the case, change the resistor from 1K ohm to 100 ohms.
REQUIRED PART
100 OHM, 1/6 WATT RESISTOR.......RD14CB2C101J
PROCEDURE:
1. Disconnect the power supply and antenna from the
transceiver.
2. Using a #2 Phillips screw driver, remove the 9 screws
from the top cover of the transceiver. Remove the cover
and unplug the speaker wire.
3. Locate resistor R172 on the component side of the IF
board (Figure 1).
4. Using a #1 Phillips screw driver, remove the 7 screws
that secure the IF unit to the chassis of the
transceiver.
5. Pull the board up and rotate it towards the front of the
transceiver to expose the foil side of the board.
6. Desolder and remove resistor R172 from the board.
7. Install and solder the 100 ohm resistor in place of
R172.
8. Assemble the transceiver by reversing steps 1 - 5.
This modification may be covered under warranty.
Time required for this modification is 0.5 hrs or less.
(C) 110888TKC