HELP! icf-sw100 repair problem with keypad

HELP! icf-sw100 repair problem with keypad

Post by Andreas Rie » Tue, 13 Jan 1998 04:00:00

HELP! icf-sw100 repair problem with keypad

I  need help. My Sony icf-sw100 have a problem. The keypad did not
work, but
the display shows the time and the backlight works also. The main
switch is on
(green switch) but the radio doesn=94t work: no radio and I cant set
the time, the "hold key" has no response. A reset changed nothing on
the problem
but then the time shows the default value (0:00 flashes and timezone
London). I also changed the batteries.

It is the second time that this radio has a problem, the first time
was a problem with the connection to the display.

Is there anybody out there who can help to fix the problem. I know to
use a
 soldering iron. The warranty of the radio has ended.

Andreas Riese


HELP! icf-sw100 repair problem with keypad

Post by Michael Rathb » Tue, 13 Jan 1998 04:00:00

In on 12 Jan 1998 19:10:00 GMT,

>HELP! icf-sw100 repair problem with keypad

The symptoms indicate that you may have had (another?) failure of the keypad
signal flexible printed circuit board (ribbon cable).  The point at which the
ribbon cable leaves the lid assembly is extremely sharp; for plastic, it is a
pretty good wire cutter.  Over time the stress can be too much for the copper
conductor, and various keyboard functions stop working.  If this is the source
of your problem, no soldering is required, as the ribbon cable is socketed.

You can check the condition of the ribbon cable by disassembling some parts of
the receiver and inspecting it.  If you have the correct screwdriver, you may
remove the lid portion to look at the cable; if not, you may disassemble the
upper and lower halves of the receiver and remove the cable from the receiver
for inspection.

The upper lid portion disassembles easily, as the two halves snap together.
The ribbon cables slip into two sockets on the circuit card.  The sockets have
locking strips that should be released before removing or inserting the ribbon

The lid assembly is held on by two long screws requiring a small (about 0,7
mm) cross-point screwdriver.  It is very easy to damage these screws with
incorrect tools or careless operation.  Separating the lid pieces, unplugging
the cables and removing the screws allows you to look at the portion of the
keyboard cable that would have been in contact with the sharp portion of the
lid.  The break in the conductor may be very difficult to see -- nothing more
than a slight discoloration of the copper at the point of the break.

If you do not wish to dismount the lid, you may disassemble the base portion
of the receiver as outlined in the post attached below in order to remove and
inspect the conductor.  

If it appears that a break in the ribbon cable is the cause of your problem, I
include an informative post below, giving the part number to order and better
instructions on the mechanics of the repair.

Separating the lid and base assemblies of the receiver for either inspection
or repair gives you the opportunity to use a small file to dull the extremely
sharp edge that causes the fatal bend in the conductor.

Quote:>It is the second time that this radio has a problem, the first time
>was a problem with the connection to the display.

Do you know whether this was fixed by replacing the ribbon cable?

The following message, with an additional detail I have added, describes
repairing the ribbon cable:

In on 11 Oct 1997 16:56:03 GMT,

>The Sony ICF-SW100 has a notorious weakness: the flexible circuit
>board that connects the lid to the chassis tends to fail. Mine did
>so after about two and a half years of use. I managed to repair
>it, and I'm writing this to help anyone else who might want to
>attempt a repair.

>There are three circuit boards in the SW100: the "microcomputer"
>board in the lid, and the "key" and "tuner" boards in the chassis.
>The "key" and "tuner" boards each connect to the "microcomputer"
>board by a "flexible PC board". There are thus two separate
>interconnections, called by Sony the "key" and "signal" flexible
>PC boards,

>In my case, it was the "key" flexible board that failed. The first
>symptom was that the Main Power switch on the side could not turn
>the unit off. After a few days, several of the keys stopped working.

>The cover of the lid is held on only by plastic claws, so it is
>easy to remove. The chassis portion has four screws in addition to
>claws: remove the screws identified by arrows on the bottom piece.
>The fifth***you'll see (with no arrow) anchors the whip antenna:
>it need not be removed. Once you've removed the screws and unhooked
>the claws, the chassis separates into three pieces: the upper part
>consisting of the lid, the top of the battery case, and the keyboard
>cover, the middle part holding the two circuit boards, and the
>lower cover.

>The flexible boards plug into connectors on the circuit boards, so
>no soldering is necessary. The boards are routed through a slot by
>the lid hinge. They only move freely when the lid is open: with
>the lid closed they are tightly pinched (this may be the origin of
>the problem).

>Be sure to fold the replacement the same way the original was
>folded. The silvered fingers on the end go toward the board when
>you plug it into the connector. It's a bit difficult to get the
>end into the connector without buckling.

The connectors into which the ends of the flexible circuit board slide are
fitted with a bit of white plastic which is a lock/release mechanism.  Before
pulling out the damaged flex board, pull out the lock/release piece.  When
inserting the replacement part, be certain that the lock/reliece piece is
pulled out; the flex board will then slide into the connector quite easily.
When it is seated, push the lock/release piece into the connector.

- Show quoted text -

Quote:>As is usual with Sony products, reassembly is a bit like trying to
>line up a dozen live worms. Getting the plastic keys and the Main
>Power toggle to stay in place while you snap the chassis together
>is tricky, especially with the lid open to keep the flexible boards
>from jamming. Once the chassis is snapped together, the rest is

>Sony part numbers for the replacements are:

>1-651-256-11 PC BOARD, FLEXIBLE (KEY)

>Beware that in the service manual, these part numbers are interchanged:
>"Supplement 2" to the manual corrects this error.

>In the USA, Sony parts can be ordered by calling (800) 488-7669.
>These are about $11 apiece.