For reference, it's P/N CW2605.

Picked up, at my not-so-local electronics parts store in Greenbrook NJ the circuitworks rubber button repair kit last weekend...my remotes for both the XJR and XJ8 were exhibiting the gradual loss of reliable function...so, with nothing to loose (considering that to replace all 4 would be over $1000 if I wanted brand new) and everything to gain, figured I would invest the $16. in a kit.

Decided to do the older car (the XJR) since neither of the remotes worked at all. Took the lessons learned from that and applied to the XJ8 remotes.

First it should be said that the kit contains the metal paint, a catalyst, a stirring rod, q-tip, and small paint brush.

You activate by pouring the small bottle of catalyst into the paint container, and stirring for a couple minutes to fully mix the paint. It has a (according to the instructions) 72 hour pot life, so, it should be good for your fobs, dodgy TV remote, etc. There is enough, I estimate, to do a whole pile of fobs AND the TV Remote...so, line them up.

I disassembled the fobs, being careful to not press the buttons whilst taking the assembly apart. Taking the rubber buttons off the circuit board, I noted that the gold contacts on the circuit board were crudded up with what can only be the remains of congealed rubber and carbon; using some contact cleaner and a static-free towel, I cleaned off the contacts on the board and set them aside.

Retiring to the sink, I thoroughly washed both the rubber button pad and both halves of the fob. Amazing the crud that builds up around the base of the buttons and the holes and seams of the fob...anyway, dried with a paper towel, and heat gun set on low.

Reassembling the buttons into the front of the fob, I then dipped the q-tip into a bit of isopropyl alcohol and proceeded to clean the contact side of the buttons, paying attention to clean the raised pip which is where the contact is made. The alcohol flashed off...and ready to go.

Opening up the jar of contact paint, dipped the included brush in, and proceeded to put on *gently* the paint. I found that if you hit the tip of the pip with the end of the brush (you don't need much paint at all), then smoothing it out over the entire surface, it's possible to get a reasonably smooth coat of paint to cover the contact end. I also found that if you are careful, and put the second thin coat on at 90 degrees to the first, you can achieve full coverage over the contact. You will know you've done enough when you can BARELY see the underlying cross-hatch pattern in the original contact.

They state in the instructions that full drying takes 24 hours, but that raising the temp to 190 degrees (I used a hot air gun, set on 190) and gently warmed the back of both button packs when I was done with painting the tips of the 8 contacts, then set them on my shelf.

Reassembly, as they say, when the paint had flashed off for a day, is the reverse of disassembly. Took the opportunity to also replace the coin batteries with new CR2016 cells.

So...how did it work? Well...testing the restored fobs on the XJR proved that the repair kit did what it says. Two fobs which were extremely dodgy in operation now work opening, locking, releasing the trunk, and turning on the headlights from 50' away (no, didn't put it next to my head and open my mouth...), and better yet, worked without having to continuously push the button nor honk down on it.

Doing the XJ8 remotes now. That's how confident I am that it works.

So, if you have dodgy fobs...and are careful and follow the directions...may be, for $16 USD, a cheaper and better fix than aluminium tape disks or tin foil and gorilla glue.


Repaired contacts; you can see the pattern showing through the contact paint. Circuitworks claims 500,000 contact closures tested. We'll see how that works out in the crucible of Jaguar ownership...lol

 

Now this is going to have some followers for sure, worth a 'sticky'.

My only question mark should be on how it holds on to the flexible rubber pads, but I guess they sorted that out long time ago.

Thanks very much.

 

I've had good luck so far with just having scrubbed the pad and contacts with rubbing alcohol and paper towels. Took a few tries and a surprising amount of force when scrubbing the pads but it seems to work fine now, even though the cross-hatching pattern was completely gone on the lock/unlock buttons. If it craps out again, I'll be sure to order this kit though.

 

My old XJ had this type of remote, and I had it modified by having the later buttons fitted to the circuit board. This was an eBay service that cost me about £10 to have done including new battery.

It's useless to me now as my new XJ is an 02 car so has the later remote.

 

I still manage to have them working fine by cleaning them up once a year.

However, how does that original fob actually work?
Does it establish connectivity by just pushing that rubber pad against the board and its contacts?

 

It's a common way of building membrane switch controls; where you see the paint in the photo above is actually a carbon button that is bonded onto the rubber that makes the contact. It's actually a quite interesting way to do it. On the circuit board, there are gold plated contacts, in concentric circles, which, when you press the button down (and this is assuming that it's not worn down so that it can't close the circuit), closes the circuit, and the signal which is pre-programmed into the device for that contact is transmitted.

Actually pretty neat.

Hope the above helps...anything to keep these things going, right?

(If anyone is in the area and having the problem...and doesn't want to do it, let me know...may be able to work something out...)

 

Oh, by the way...did the XJ8 fobs yesterday...left on the bench overnight after gently warming them as above...reassembled and tried out this morning...they work a treat.

Think we may have found a winner for the X305 community.

 

Thanks for the more than helpful explanation, never thought of carbon, but of course ...
Do you have, by coincidence, a picture of the packaging of that stuff?
Or a link?

Will try to get some here in Taiwan, but I guess my Chinese is not sufficient to explain what I am looking for.
Might be able to get something from the internet or something local if I got a at least a lead.
Who knows, probably made here .

 

Not the best...had thrown out the packaging...but, this is what the card looks like:



Here's the link to the data sheet:
http://www.alliedelec.com/m/d/9ee593...39c1394d95.pdf

 

4 days on since using the kit on the 4 fobs I have.

Report: They all still work, all functions, both cars.

Conclusion: Think this is a keeper fix for the older cars. FWIW, ok, no guarantees, no implied merchantability, etc. But, for me, spending the few bucks and getting useable fobs without the aggida of buying used ebay or, heaven forbid, new from the dealer...for the price of the kit and an hour of my time was worth the experiment.

 

Thanks Bryan, that should help for sure.
Keep us updated how it is working in a year or so .

 

Thanks for this great tip, Bryan!

I've added a link to this thread to the X308 'HOW TO' quick links.

Cheers,

Don

 

Bumping this so I can finally finish my FOB.

 

Well this task was a miss for me lol. Guess I was a bit too rough on my rubber keypad cleaning as the already torn lock & unlock(most used) keys completely tore free. Looks like I'm back to E-Bay for another FOB.

 

I used the search and it worked
Thanks for the good post
I will be trying a circuit writing pen.

 

Does it really use 2 CR2016 batteries?

First time to see 2 coin batteries stacked on top of each other.