RickyGee

Well, I think I'm done playing. I've made 4 needles and have one that I'm happy with and will be road testing today. The EL wire proved very disappointing for many reasons. The 3.0mm ccfl is way too fat. So I made the 2.6mm ccfl work. It turns out that you can vary the luminescence by varying the width of the conductive film; wider=brighter, narrower=less bright, and you don't have to use the end electrode at all, so the wire can be snipped off. 2.6mm is too wide for the needle base which is precision molded for the 2.3mm OEM needle, so I had to use a dremel tool to shave down the ridges in the base and cap a bit. I also had to open up the center of the base a bit to accommodate the slightly larger end of the ccfl. The 2.6X61mm ccfl I got from Digikey is about 8mm short of the original, so the end of the ccfl is in the middle of the base, rather than sticking out the back. Here's a picture of the needles.

RickyGee

Balance was the next big thing. The gauge is very sensitive to weight and balance of the needle. When the unit is off, the needle comes to rest on the physical needle stop (which if it has any lube on it will cause it to stick...) which is slightly below 0 mph. When the power is applied, the forces balance to bring the needle up to the 0 indication. The screw on the back of the cap provides for minor adjustment, but I had to add weight in the form of copper foil to the electrode end and then shave a bit off the balance screw in order to get the assembly into range for the screw to work. Here's the needle installed.

RickyGee

And here's the finished product. I haven't tried the dimming circuit yet. I'll do that in the car later today, when I road test it and time the speedometer to make sure it is accurate. The new ccfl is not quite as evenly bright throughout its length as the original is (note the tach needle which is original), but it's really close. If I had it to do all over again, I would buy the 2.3X72mm from BackLight4You in Germany and pay the 30 Euros ($50). I think it would be a virtual drop in with much less fuss than I went through. Wish me luck on my test drive! -Rick

Och

iTrader: (3)

Ricky, great work. Just FYI, when the factory cluster dims, the needless do not dim, its just the backlights that dim.

drewkaree

Either I missed it, or I'm just having a brain fart. What'd you use for the conductive film?

RickyGee

I used 5 mil (0.005") copper foil tape with conductive adhesive. 3M 1181 or JVCC CFL-5CA meet this spec. I bought a roll of 1/4" X 36 yards from FindTape for $10. That way, I could experiment with a wide variety of shapes and sizes and simply pull it off to start over. The final product was a strip that was 0.040" at the base and tapered to 0.090" at the tip, applied to the back. Then a strip about 1/8" was cut and applied circumferentially at the outer metal clip to make the electrical contact. At the electrode end, I used a piece of insulation stripped from the EL wire to cover the wire, then wrapped the wire back over the end, covered it with a copper foil band and soldered it. I had to add a bit more for weight later on.

One of the hardest parts was getting an acceptable quality paint finish. I had to cut an 0.050" strip of aluminum foil tape to use for masking, and it was a real pain in the a.. I painted, stripped and repainted a half dozen times before I got a stripe that was crisp enough, and it's not perfect. I tried brush and spray applications, and finally used spray Rustoleum Industrial gloss black enamel, over the copper foil, and pulled the masking foil about 5 minutes after spraying, while the finish was still pretty soft.

By the way, it worked during the road test, but I'm not thrilled. My bench setup used a 12vdc power supply and the needle was very close in brightness on the bench. But when installed, and looking through the smoke glass outer lense, it's noticeably brighter than the stock units, and the color difference is more noticeable. The OEM units have a slight greenish cast and the new needle is more blueish. It does dim, though, with the dimmer control. I'm going to live with it for a while, but I can't honestly recommend it to anyone who is fanatic about their LS400. But if you're thinking about the Kluge fix with the uv bulb and some blacklight paint, this is definitly much closer to the original that that.

nchavez430

I just repaired my instrument cluster needles, with a 10 dollar conductive paint pen that I bought from radio shack.

LexLS

It's great you fixed your needles but could you please elaborate and possibly post some pics for us? For example, what product exactly did you get, how did you apply it, etc. This would be helpful as the needle fix issue has yet to be fully documented with a solid fix.

somnoboy

Yes, please. A detailed write-up would be greatly appreciated!

nchavez430

I'm pretty sure any type of conductive paint that you can get will work.

1: Remove instrument cluster from car, remove black tinted cover

2: Remove old (black) flaking paint off of needle, being very careful

3: Use a small flat paint brush to paint the back of the needle all the way to the base of the needle. I'm not sure if it matters or not but I applied the paint to the metal prongs that are holding the needle in place. Be Careful not to cover the front of the needle or you'll have dark spots.

I'll take some pics of the paint pen that I bought when I get some extra time.

Good Luck

fencera

Fortunately, a how to already existed!

https://www.clublexus.com/forums/ls4...ml#post5559611

A little after the pictures, I wrote a few notes about my experience. It works exceptionally well although you must be very careful.

SoarUnsore

Fencera, great find with the link. It seems like that will work to fix the problem of the half-lit needles.
However, I'm confused as to why... It was my impression that the issue with the illumination was that the white fluorescent stripe was what reacts with the electricity, giving illumination. But if that's the case, why does the write-up expressly shy away from applying the defogger paint to the edge of the stripe? Does the electricity only need to be brought to the tip of the needle to illuminate the far half?
Oh, and does the defogger paint go underneath the black outer plastic casing?
The write-up is fantastic, but I'm afraid it leaves questions for those wary of attempting something they do not know all the facts to.

fencera

Hey-

So after doing the needle painting 'procedure' successfully, my understanding of why the process works is this:

Speedo, tach, water temp and gas all use small ccfls for illumination. They, as most bulbs, require a + and - to power on. The one end is no problem given the needle is mounted on the gauge. The far end ("pointing end") also requires electricity. It gets that through the conductive paint on the back of the needle.

The original paint completing this circuit has failed on many of our cars after 20 years. However, it's very tough to see this through the tinted shield of the instrument cluster... it's almost impossible to see the flaking of the paint and cracks on the back/sides of the needles until you take it apart.

Once you have taken your instrument cluster out, you will be able to look closely at the needles. You'll see cracks in the black paint on the back of the needles and perhaps flakes of black paint falling loose. These are what need to be covered over with the conductive paint. Since the color won't match, you then paint the sides and visible portions of the needle (mainly the back) flat black to match.

I hope this explanation combined with the original tutorial Ii linked to and my brief notes on my experience answer all your questions.

PS: This is the paint I used: Permatex 15067 Quick Grid Rear Window Defogger Repair Kit

paulybear

Just wanted to add something to this thread encase someone still wanted to do this mod because of burned out or broken speedometer/ tachometer needles (my case is the latter) :-( I found a company online that also sells cold cathode bulbs of similar size to the first gen ls400 needles. 2.2 mm X 61 mm is the size I'm going to try. They shipped same day and fixed a mailing address problem within a couple of hours after I emailed them after hours. Wow, great Costomer service! The company is called Lexim LLC. You can buy a package of two bulbs for under $12.00. Around $8.00 shipping. I'm going to try the conductive paint. We'll see how it goes and I'll repost on my progress.

paulybear

Well here is an update on my progress if you can call it that. I received the ccfl 61mm x 2.2mm bulbs in four days regular mail from Rexim LLC and started my own experiments with the help of Ricky's info in mind. I decided against using the conductive paint after doing some more research on the subject. The best liquid conductive coating (paint or paste) seemed to be the black hobby brush on conductive type but it is a bit expensive as is the copper paint. Other paints (that use carbon, aluminum and platinum fillers) seemed kind of iffy. Most are water based acrylic which are ok to use in household projects that are not subject to temp and humidity extremes like the inside of a vehicle. Not sure how it would hold up. The carbon paint was not as conductive as the others and the aluminum tends to corrode in moist environments and break down. Pastes are too sloppy, thick and heavy for this project. I wasn't about to spend $150.00 to $250.00 on paints and pastes to experiment with for a one time use. Paint pens are $10.00 to $25.00 on line and now $23.00 at Radioshack. This might work ok but doesn't seem like it would coat evenly and you would still have to paint black over it. The rear defrost repair kit is a paste/glue that you have to mix then apply with a very small brush. Didn't look like there was much copper in it though. Probably would work fine in repairing existing black paint but kind of messy for coating the whole under side of the needle. Keep in mind that you have to experiment with the width of paint on the bulb to get the correct brightness to match the brightness of your other needles (then paint, strip, paint, strip etc till you get it right). You have to let the paint set up completely before you test each time. Too time consuming. So I decided to go with the copper foil tape. I'll continue later. Paul