TS440S.4

From: N0JN@DU1JMG
To: ALL@PHL.
Subject: TS-440S bad ROM socket.

89/02/04 AT 04:45    FROM  NV7L  TO  ALL

WARNING TO KENWOOD 440S OWNERS

AFTER SEVERAL MONTHS OF FRUSTRATION I DECIDED TO FIND OUT WHY MY 440S
WOULD GET FLAKEY (DISPLAY WOULD GO CRAZY OR DISAPPEAR THEN THE RIG
WOULD GO STOP TRANSMITTING OR RECEIVING) WHEN IT WAS COLD.  I COULD OFTEN
RESET THERCONTROL CIRCUIT BY PUSHING THE A=B BUTTON WHEN TURNING
THE RIG ON BUT A FEW MINUTES LATER THE RIG MIGHT AGAIN GO TO NEVER-NEVER
LAND.

AFTER SEVERAL HOURS OF ATTEMPTING TO TRACK DOWN THE PROBLEM I DECIDED
TO TRY SOME FREEZE MIST ON THE MAJOR COMPONENTS ON THE CONTROL BOARD.
THE RIG CAME TO LIFE WHEN I SPRAYED IN THE AREA OF THE 27128 EPROM
THAT PROVIDES THE PROGRAMMING FOR THE CONTROL CIRCUIT.  IT WAS CLEAR THAT
EITHER THE SOCKET OR THE EPROM ITSELF HAD A PROBLEM WHEN REMOVING
THE EPROM, CLEANING THE HOLES IN THE SOCKET, AND REINSERTING THE CHIP
BROUGHT THE RIG BACK PROBLEM FREE OPERATION.

A CALL TO THE SERVICE DEPARTMENT AT KENWOOD CONFIRMED THAT THEY HAVE BEEN
HAVING PROBLEMS WITH THE EPROM SOCKETS.  THEY RECOMMEND REMOVING THE
SOCKET AND SOLDERING THE IC DIRECTLY TO THE CIRCUIT BOARD.  THIS IS VERY
DIFFICULT UNLESS ONE HAS ACCESS TO A VACUUM DESOLDERING STATION AND HAS
EXPERIENCE WITH WORKING ON CIRCUIT BOARDS WITH TINY PADS AND TRACES.

SINCE I DON'T HAVE A DESOLDERINGSET UNIT, I DECIDED TO SIMPLY TOUCH-UP
ALL THE SOLDER JOINTS ON THE SOCKET AND ONLY ATTEMPT TO REMOVAL AS
A LAST RESORT.  SO FAR THE 440S HAS WORKED FLAWLESSLY SINCE DOING THIS.

I HOPE THIS INFORMATION WILL BE OF HELP TO ANY AND ALL 440S OWNERS.

73, DAN VAN HOY, NV7L
BOX 256
NASELLE, WA 98638
206-484-3817
============