From: wa2ise
Newsgroups: rec.radio.amateur.misc
Subject: TS440 Q33 protection
Keywords:fix
Message-ID: <1991Dec10.045038.26685
Date: 10 Dec 91 04:50:38 GMT
Sender: news
Organization: AT&T Bell Laboratories
Lines:59
copied from packet:
Msg# TSF Size #Rd Date Time From MsgID To
8731 BF 1957 0 08-Dec 0343 KD2EJ 28523_WB2QJA INFO
Sb:PROTECTING Q-33 ON TS-440S
SB-949
TS-440S PROTECTI 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
1Disconnect the power supply and antenna from the
transceiver.
2Using a #2 Phillips screw driver, remove the 9 screws
from the top cover of the transceiver. Remove the cover
and unplug the speaker wire.
3Locate connector 19 on the IF unit.
4Using a #1 Phillips screw driver, remove the 7 screws
that secure the IF unit to the chassis of the
transceiver.
5Pull the board up and rotate it towards the front of the
transceiver to expose the foil side of the board.
6On the foil side of the board, locate the trace that is
connected to pin 3 (brown wire) of connector 19.
7Using a craft knife, cut the trace comming from pin
three so as to open the foil trace.
8Solder the 4.7 ohm resistor across the now open trace
(i.e. in series with the trace).
9Assemble 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.
© 112188TKC
=====================================================================
Note:I haven't tried or verified this, proceed at your own risk. WA2ISE
SOURCE: The QRZ Windows Ham Radio CDROM |
