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World of Ham Radio 1997
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==============================================================================
K E N W O O D
>>> A M A T E U R R A D I O S E R V I C E B U L L E T I N <<<
==============================================================================
Kenwood Service Centers
Kenwood Service Corporation Kenwood Service Center, East
2201 East Dominguez Street 829 Lynnhaven Parkway, Suite 130
Long Beach, California 90801 Virginia Beach, Virginia 23452
Telephone 1-310-639-5300 Telephone 1-804-340-1702
==============================================================================
BULLETIN # 967
MODEL: tm-701a
SUBJECT: INTERMITTENT MEMORY LOSS
Some TM-701A owners have reported that the transceiver intermittently
loses its memory channel information at power on. The following modification
will absorb pulses on the CPU interrupt line (INT4) and reconfigure the
backup switching circuit to avoid unintentional memory loss.
This modification should be performed on a Dealer level as they have the
correct tools to disassemble the transceiver.
REQUIRED PARTS:
220uF, 6.3V ELECTROLYTIC CAPACITOR CE04NW0J221M
0.01uF CERAMIC CAPACITOR CK45B1H103K
0.022uF CERAMIC CAPACITOR C90-0475-05
2.2K OHM CHIP RESISTOR RK73FB2A222J
1K OHM CARBON RESISTOR RD14BB2C102J
3.0V ZENER DIODE MTZ3.0JB
1. Disconnect the power supply, antenna, and microphone.
2. Remove the top and bottom covers (12 screws). Disconnect the speaker
plug when the top cover is removed.
3. Remove the knobs from the front panel.
4. Remove the nut from the microphone jack and the 11mm nut from the
channel selector switch.
5. Remove the 4 screws that secure the front panel to the body of the
transceiver.
6. Pull the front panel off the transceiver to expose the Control board.
7. Remove the 3 screws from the Control board. Gently pull the board off
the transceiver.
8. Perform the changes shown in the accompany diagram. C202 is on the
component side of the Control board. All other work will be done on
the foil side of the board.
Time required to perform the modification is 1hr. or less.