[Kenwood] TS-440, replaced lamp, cleaned Keypads (how I did it). Long Post.

[Philip KO6BB]

Hi,

NOTE:  It took me longer to write up this "procedure" than it did for me to
do the work! But I wrote it up in such a way that (I hope) even a complete
idiot could clean their "bouncing keypads".  NO, I'm not calling anyone here
an "idiot", I just wanted to be as complete and concise as possible as I
realize that not everyone has over 50 years of electronics technical
"expertise" under their belts ;-)

NOTE:  While NOT tested, the same cleaning procedure 'should' work on a
R-5000 that has "bouncing Keypads".

List chatter on the TS-440 mail group about replacing meter lamps prompted 
me to go ahead and change mine, which burned out about a week ago.  I used a 
14 Volt, 80mA miniature "leaded" lamp and put a 27 Ohm resistor in series 
with it.  It fit the green rubber "boot" well.  Then I checked the Voltage 
across the lamp, it measured 11.6 Volts (radio is running on 13.6 Volts). 
No, it's NOT really bright, but is sufficient to see the meter well.  AND, 
the lamp will probably last forever 8^)

When I bought this radio from a friend, perhaps 2 weeks or so ago I didn't
think it had any keypad bounce (it DOESN'T have the brown PLL glue that
causes problems), but close testing of it proved that it did.  Perhaps one
time out of 4 when I pressed a digit I'd get a "string" of them.  Since I
had the radio on a "trial" basis until my income tax came in I had the
option of returning it to it's owner if ANY problems cropped up.  But the
radio is so "super clean", and otherwise worked perfectly I decided to keep
it.  Besides, I DON'T do direct keyboard entry of frequency all that much,
preferring to select a "band" then cruise it.  The pads worked perfectly for
selecting modes etc. (in which "keybounce" wouldn't impact operation).

Anyway, while I had the front panel off I decided to clean my keypads and
see what resulted.  Although I have a downloaded copy of the service manual
that I printed, I DIDN'T find it necessary to even get the manual out for
removal of the front panel OR disassembly of the keypad (this ISN'T rocket
science).  As someone mentioned, there ARE a lot of very small parts, so
great care is required.  Total time for the work, from the time I took the
radio out of service until it was re-installed in the operating position was
about 2 1/2 hours, including the time I took to refill my cup with "jitter
juice".

CAUTION:  IF YOU CAN'T HANDLE SMALL PARTS OR HAVE A MEDICAL PROBLEM WHERE
YOUR HANDS SHAKE BADLY, DON'T TRY DISASSEMBLING THE KEYPAD!

Here is how you do it, step by step.  I suggest you have ALL needed supplies
and tools at hand before starting.  Put a dark colored towel or similar on
the work table so that if you drop a tiny, shiny screw or something you can
see it.  A good, lit, magnifying glass to work under will help too.

Tools and supplies needed.
1.  Screwdrivers, #2 and #1 Phillips, TINY screwdriver for the Phillips head
screws in the keypad.  NOTE:  I had 5 different Phillips Jeweler's
screwdrivers, NONE were small enough.  I used a TINY (smallest size) flat
blade Jeweler's screwdriver, it worked well.  MAGNETIZE your screwdrivers to
make work easier.

2.  At least One pair of tweezers, two pair is better (one sharp point, one
flat blade).

3.  A Metric Allen-wrench to fit the large tuning knob (don't know it's
size).

4.  Generous supply of round wooden toothpicks and Cotton Q-Tips.

5.  Bottle of Isopropyl Alcohol, (I suggest the 91% stuff available at
drugstores).

6.  Quick setting, FLEXIBLE adhesive.  This is mostly to hold things
together during re-assembly.  I used "Amazing Goop Marine Contact Adhesive"
available at ACE Hardware stores.  DO NOT use RTV Silicone compound as the
acidic fumes may recontaminate the pads, undoing all your hard work
(besides, it's conductive till it sets well).

7.  Several small bowls or other containers to hold parts as you disassemble
the radio.  I find it convenient to put the outer case screws in one
container, set it aside, the screws and knobs from the front panel in
another container and set that on top of the first, and so forth, stacking
them up in the order of removal.  That way, as you reassemble the unit you
work your way down the stack of hardware containers and don't get the
hardware all mixed up.

OK, HERE WE GO (step by step details). . .

1.  Remove Top and bottom covers, putting the screws into a container.
CAREFULLY unplug the top speaker lead from the circuit board.  DON'T LOSE
the black felt pad from the top mounted slide switch.

2.  Remove ALL knobs from the front panel and set them in a bowl or tub.

3.  Remove the circular nut that secures the mic connector in place.  This
is easiest done by using a pair of needle nose pliers with needle-like sharp
jaws and putting the tips of the pliers in the slots cut into the nut.  Put
this nut in the same tub with the knobs.

4.  Remove the two screws that lurk under the tuning knob AND the two black
front panel securing screws on either side of the radio.  Put the screws AND
their washers in the same tub that contains the knobs.

5.  Carefully slide the front panel off the face of the radio, being CAREFUL
NOT to lose the little rectangular knob that slides onto the Meter select
switch (I spent 10 minutes looking for mine).  Place the slide switch knob
with the others and set that tub aside.

6.  Tip the radio on it's back so that it's facing up (careful NOT to knock
it over).  Remove the 4 small silver screws that secures the keypad in
place.  Put them in a SEPARATE tub, and set that tub aside.

7.  Carefully pull the keypad from the front panel and unplug the 3 cables
that connect it to the rest of the cable.

8.  SET THE RADIO ASIDE IN A SAFE PLACE.

NOTE:  Magnetizing your screwdrivers with a magnet will make the following
steps easier to accomplish.

9.  Carefully examine the Printed circuit side of the keypad to get a feel
for how it's assembled.  Remove ALL the tiny Phillips head screws that holds
the circuit board in place (it seems like there are a gazillion of them, I
didn't count them).  This is where you need that TINY jeweler's screwdriver.
OBSERVE that there are TWO screws with washers on one edge of the board.
Make note of their positions (they are the holes that aren't enclosed on one
edge).  Put all the screws in a tub where they WON'T grow legs and
disappear.  Screws of this size can be a pain to find replacements for. . .

10.  Observe that ONE LONG edge of the circuit board is secured to the
plastic frame by a black fabric like material.  DO NOT peel the circuit
board from this, but leave it attached!

11.  Carefully fold the circuit board back, working it around to clear the
plastic lip as you do so.  When finished you should have TWO pieces, joined
along one edge laying FLAT on the table top. DO NOT TURN OVER OR YOU WILL
HAVE TO PLAY "GUESS WHICH HOLE THIS BUTTON GOES IN".  The buttons are NOT
secured to the front panel.

12.  Examine the circuit board.  You will see that there is a thin, clear
plastic membrane that covers all the keypads.  This appears to be bonded to
the circuit board, making the tactile buttons one with the board.  This is
NOT the case, it will pull up fairly easily.

13.  Decide which side of the board you wish to start on first.  Since I was
"committed" and didn't think about it, I started with the mode key side, the
side with 16 keys.  You may wish to start with the smaller one.

14.  Using your tweezers, VERY carefully lift up one edge of the clear
membrane and SLOWLY peel it back.  A number of pads will probably stick to
it or otherwise get displaced.  DON'T worry about it, ALL the keypads are
going into the bowl anyway.  Just DON'T let one of those critters grow wings
or legs and fly off to "no-where land"!  If you do, you're only recourse
will be to try to find a keypad from a junked radio.

15.  Using your tweezers, CAREFULLY pick each one up and put it in the bowl,
being careful NOT to deform or dent them in any way.  If yours were like
mine, they will be in VERY good condition physically, but have a gray or tan
film over them.  Since my radio was NOT from a smoking environment I can
only suspect that it is either metal oxidation OR a chemical film from the
electronic parts in the radio.

16.  NOW, we get down to the actual cleaning.  Soak a Q-tip in the alcohol
and carefully swab ALL the gold contacts on the circuit board.  Don't worry
about being generous with it, it'll dry quickly.  Likewise, don't be stingy
with the cotton swabs, they're cheap! Once the pads are clean, keep your
fingers or other contamination OFF these gold pads!

IN THE NEXT STEPS YOU WILL WORK WITH ONE KEY METAL MEMBRANE AT A TIME,
PLACING IT ON THE CIRCUIT BOARD BEFORE PICKING UP THE NEXT ONE.

17.  With the tweezers carefully pick up a metal switch membrane and lay it
face down (4 legs up) on a smooth, hard surface.  Holding it in place with a
toothpick, take an alcohol soaked cotton swab and gently "scrub" the
surface.  Apply enough pressure to make sure that you're thorough, but DO
NOT damage the little contact legs or deform the membrane. IF you're lucky
enough to have access to an "Ultrasonic Jewelry Cleaner" by all means use
it, BUT CLEAN THE MEMBRANES with Alcohol afterwards to make sure that the
cleaning fluid doesn't have any contaminants!

NOTE:  YOU DO NOT need to clean the outer surface of the membrane, the side
the plastic push-button pushes on.  To do so might deform the membrane.
Remember, these things must retain their "spring" if they are to work
correctly.

18.  Using your tweezers carefully lay the membrane down in one of the
switch positions, being careful that the 4 contact "legs" rest over the 4
gold contact pads on the circuit board.  There is STILL a clear plastic
membrane over the contact surface with cutouts that help hold these
membranes in position.

DO STEPS 17-18 FOR ALL THE METAL KEY MEMBRANES, ONE AT A TIME. (It's easier
and safer to complete one membrane before cleaning the next).

IMPORTANT NOTE:  USE A FRESH Q-TIP FOR EACH MEMBRANE.  You don't want to
transfer the film from one switch to the next one.  As I did this I noticed
that some of the q-tips had gotten some definite "color" off the membrane,
indicating that I was indeed removing some sort of film contamination
(again, this radio was a "non smoker", it's way to clean inside to have been
smoked around).

NOTE: This next step MAY be the most difficult and critical of the whole
job.

19.  When all the membranes on one side are clean and IN THEIR PROPER PLACE,
pick up the plastic cover that was over the pads.  Observe how it needs to
be oriented.  Using a toothpick, put a SMALL amount of clear, FLEXIBLE
adhesive (NO RTV Silicone) between the locations of the various keypad
membranes. Using your tweezers (One pair on each side is best), lower the
plastic sheet over the switch membranes, BEING CAREFUL NOT TO DISLODGE ANY,
and gently press into place, squashing the glue down.  DO NOT get any glue
on the metal membrane switches, you want just enough to secure the plastic
sheet AND make sure that the membranes stay in place.

20.  Repeat steps 14-19 for the bank of keypads on the other side of the
circuit board.  Since you're already an old pro at this by now, it should go
smoother 8^)

21.  While you're allowing the glue to somewhat set and the alcohol to dry,
go get yourself some refreshment and take a break.  However, I don't suggest
too many "Adult Beverages" before assembling your radio <grin>. (I don't
drink alky-haul).  After this the rest of the job will be a piece of cake!!!

22.  OK, now you can reassemble your radio.  Here we go.

23.  Carefully fold the circuit board back into place, lifting it up to
clear the lip on the edge of the plastic.  There are some small round
plastic "centering posts" that will fit in holes in the circuit board.  Make
sure these line up.

24.  Install the gazillion tiny screws back into the circuit board, being
careful NOT to lose any (these keep the board from bending when you're "Key
pressing").  Like tightening headbolts on an engine, I prefer to start in
the middle and "work out".  Remember that there are two washers that go on
the screws along one edge of the board.

25.  Retrieve your radio, put it "Face Up" on the bench and carefully
re-connect the 3 flat cable connectors to the keypad assembly and remount
the keypad with it's 4 screws.

26.  NOW is a good time to Spray-clean any controls or switches that may
need it, using a good quality contact cleaner WITH lubricant.  DO NOT spray
contact cleaner in the keypad assembly you just cleaned!

27.  Clean the front panel if needed, and are-install it over the face of
the radio (DO NOT forget the little rectangular knob for the slide switch).
It may take a little gentle maneuvering to clear all the various push-button
switches.  Once in place, install the two screws that lurk behind the tuning
knob.

28.  Lay the radio back down on it's bottom, install the 2 screws in each
side of the front panel.  Install ALL the knobs etc., making sure that the
red lines of the outer knobs rotate through their proper positions (the
outer knobs can be installed 180 degrees out of whack).

NOTE:  The MAIN tuning knob MUST be pressed all the way on it's shaft or the
"Tuning Knob Drag adjustment" won't operate correctly.

AT THIS POINT I SUGGEST THAT YOU TEST YOUR RADIO BEFORE RE-INSTALLING THE
TOP AND BOTTOM COVERS, JUST TO BE SURE THAT EVERYTHING WORKS AS IT SHOULD.
TEST ALL PUSHBUTTONS TO BE SURE THAT THEY FUNCTION AS THEY SHOULD.

29.  Re-install top and bottom covers, first re-install the black felt
washer over the slide switch, then plug the speaker in properly.

ENJOY YOUR 'NEW' TS-440!


73 de Phil,  KO6BB
DX begins at the noise floor!

Ten Meter CW Beacon KO6BB/B, 7 Watts 24/7 on 28.248MCs.
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