See if that works. Not sure if maybe they need to touch something like ground or if they even matter. Seems weird they would come through the board though.

 

t-von,

Isopropyl alcohol (90+%) and a cotton swab should clean most of the old flux. Since it soaked & baked into the board, you cannot remove all of it. Do you use flux to tin the wires? There is a device known as a wire heat sync that could be used to prevent heat and solder from affecting the wire sheath. It looks like an alligator clip without serrated jaws and a round hole for wire to pass through. If you don't have this device, using mechanical hands to hold the wire will fit the bill. You have to be quick when tinning that wire though!

As for the solder points for the wires, I would advise against connecting them to the hard connector plugs. You may easily have interference between that soldered wire and the cluster connectors. Additionally, the soldered wire connected to the speedometer board has great potential for failure, such as a short circuit or wire breaking away from its solder cup. The vertical orientation of these joints would cause problems down the road. I recommend creating a wire bridge across the damaged flex print with wire or old hard drive IDE cable if you still want to repair it yourself. Follow the advise regarding jumper wire installation in a previous post.

Bear in mind that the circuit board and flex print sustained considerable damage. These types of repairs require a set of skills that a solder technician certified in micro/miniature repair could do; some of them may even struggle with it! Do you want the repair to last a long time? Or would you want to continually dig into the instrument cluster? Do you and your car deserve a repair that will last?

FWIW, please take this advice from an aviation electronics technician with 26yrs of experience: the one thing more than I hate about work is re-work. Do the repair right the first time. Save yourself the time and frustration in making these repairs work. The added wires looping around other components adds complexity during installation and removal. Not to mention the stress it has to handle while driving. I highly encourage you to find a replacement cluster flex print and/or have a skilled micro/miniature solder technician repair the damage to the board. You would be much more satisfied and have less stress knowing that the proper repair was done! Do you have other projects for your car that require more attention?

Again, I applaud you for tackling this repair but I suspect you are swimming into much deeper water than you bargained for. I'm not trying to discourage the repair just throwing out a life preserver so you don't sink, so to speak.

Cheers,
George

 

Houston,

Leave them be. They require no solder. Those should be stabilizing/support pins for the speedometer motor.

Cheers,
George

 

Repairing the damaged pins on the flex print wasn't possible for me because the plastic underneath melts instantly when the iron gets close. Those places near the wire connector on the back side is the only place with enough copper to keep heat off the flex board. What I did was tint the wire with flux, then I put a small amount of flux on top of the copper. Then I placed the tinted wire on top of the flux and cooper. Then I put a small amount of solder on the tip of the iron and rested the iron on top of the wire until fusion. Like I said before, I don't mind experimenting as a I have spent thousands of dollars on this car over the years with doing my own 100% DIY 20b swap, full fabrication, body work, and paint job so a little few hundred dollar cluster is nothing. If I get the o do working, I still plan on replacing the flex board when I find another damaged cluster. In the mean time, I'm gonna continue experimenting as that's how I learn the best.

 

Well bought a cluster from the forum hoping to end this saga of pain with my cluster which basically started with no odometer reading to a weird action with the speed starting at 20 and only going to 60. Replaced it and now everything is good but the tach basically siezering out and if calm will read maybe 3-4K rpms higher than it is. Just never ends now.

 

Houston,

Did you use the gauges from the replacement cluster or did you install your gauges? If your RPM still reads high, could it be the result of an earlier adjustment? Maybe resistance measurements are in order between the cluster and other points - ECU and Body CPU to name a couple. Speaking of which, inspect the Body CPU #2 for any damaged components.

If you installed a different cluster with gauges (not from your original cluster) and the tach is reading high then there must be something wrong with the car's wiring.

Cheers,
George

 

Swapped my old tach into the new cluster and everything is good now.

 

Houston,

Could you explain what components you used in the new cluster? And did you have to adjust the RPM on your old tachometer once installed into the new cluster? Lastly, does the Over-rev buzzer go off when it should?

Cheers,
George

 

The tach was the only part swapped as I know it worked in my old one. The three screws were removed and was a very simple change. I din't adjust anything, haven't revved high enough to hear the buzzer being with a rebuilt motor.

 

Has anyone replaced the tinted film on the LCD screen on the odometer with any success?

I've replaced the film with window tints of various grades and they look great:


until you turn the key on and try to read the odometer:


you can still see the digits however you need to look at it on quite a sharp angle to read them.


The lightest tint that i have tried is 35% and is pictured below and you can see that its a pretty close match however its just not working:


Any feedback or help would be good.

 

I wonder if the original tint is polarized or something.

Dale

 

brad,

A polarized odo screen is plausible. What happened to the odo screen to warrant an added layer of tint?

 

It looks like he's holding it in his hand, I have seen many with an "alligator" thing going on where it is all wrinkled up and crappy looking.

Dale

 

Thanks, Dale! I now see the crazing on the film.

After some thought, there may be a couple of options for Brad to explore. First, this display is an LCD screen. Any film covering the display would primarily serve as an anti-glare agent. Typical window tint is not really designed to be used with digital displays like an LCD screen. The amount of emitted light from the display is considerably less; at least that's my theory. Not to mention the possibility of the film being polarized as Dale speculated earlier. Perhaps a protective film specifically designed for LCD displays would work better? The type of film found on many phone screens could be an option. Here are 2 website to consider:

https://www.photodon.com/c/LCD-Protective-Films.html - Photodon website
Glass cover replacement for Sony NEX LCD screen Photoclubalpha - Replacing NEX LCD cover glass Article

Maybe the solution can be found in either site? I hope this helps.

Cheers,
George

P.S. I would recommend avoiding any film promoted as "anti-spy" because of its narrow viewing angle.

 

Update on th odometer screen film:

I ordered some "headlight tinting vinyl" (basically just a tinted translucent black vynil to try and still no luck:


but! luckily i had just purchased some new polarised sunglasses and gave Dales idea a crack and what do you know:


Now im on the hunt for some polarised tint or vynil or something, most likely as rare and expensive as unicorn **** considering i only need half a credit card size piece.

Brad.

 

I called it! Yay!

It's probably one of those things that there's some cheap thing you can get that from in the world. If you figure that out that would be awesome, I have seen MANY clusters with the "alligator skin" thing going on.

EDIT:
$8 for a pack of them.

Dale

 

Brad,
Well done on your experiment! Would you post a how-to on removing the old film and installing the new one? I am eager to learn about your best practices.

Dale,
Ye cup of knowledge overfloweth! Good call on the polarized film.

Cheers,
George

 

Guys,

Update: I was able to get a hold of some small size polarized film at a reasonable price via a phone screen place of all things, I've cut it and applied it, make sure you put it on with the correct orientation otherwise you can end up with the opposite of what you want. I havent had a chance to take pics yet as i am about to calibrate my speedo thanks to Mr Daleclarks how to and then i have a new cluster surround to refinish before putting everything back together, probably wont be until late february when its all done with my current work load however.

Brad.

 

For other members who seek to repair their speedometer circuit boards, please refer to this general advice link before tackling this type of repair.

General Soldering Tips-Tricks-Advice: https://www.rx7club.com/3rd-generati...dvice-1121639/

Cheers,
George

 

As I researched soldering advice from the above post, Post #294, I noticed a problem with one photo in a post. Refer back to Post #191 (https://www.rx7club.com/3rd-generati.../#post12163720). Please see the below photo and observe that C3 had a bad solder joint on the Positive (+) leg. The grey-ish and poorly filled solder joint is sometimes referred as a cold solder joint. This prevented C3 to properly work and caused a blank odometer after the bad capacitor was replaced with a new one.

Cold solder joint on Positive leg of C3.

This problem was corrected afterwards with a new capacitor and fresh solder. Sorry, I do not have a photo that shows the completed repair with proper solder joints. The repair was considered "completed" on 5 Jun 2017 in Post #222, after a long time testing the odometer. Admittedly, I am embarrassed that I didn't catch this poor solder joint when it first occurred. My intent of this post was to document and catalog this solder joint as a poor example of a repair.

Cheers,
George

 

Can anyone provide some input on my tach? The tach personality seems to vary. With bumps or just randomly it'll jump and spike over 9k rpm. It'll sit there or come back down. Sometimes it wont work at all while other times itll feel like dancing. Lastly there are even occasions when it reads low as if its only counting half the RPM not reading above 2-3k rpm when clearly the car is reving much higher. I tried jumping the ground, seemed to smooth things out a bit but notice it jumped to 9k for a moment and returned. Decided to jump a 12v at the same time. Seems more accurate with the cold idle and even just a bit smoother but yet again I saw it spike to 9k but instantly returned. Any thoughts on the chaotic "over 9000!" rpm spike? Thanks in advance.

-groovim

 

Groovim,

Please do not jumper the tach because that is a recipe for disaster. The tach gets its signals from the speedo board. Have you inspected the speedometer board for damaged caps or other components? What does the cluster flex print look like? Is there any damage to the flat ribbon cable that connects to the speedometer board?

This link specifically addresses the tach components; basically, it suggests that you desolder the IC then resolder it to the tach board. Follow the PDF file. Rev Counter Going Crazy

Use this link for troubleshooting the Speedo Board beyond the scope of this thread: Troubleshoot FD Speedo Board

Take some pics then post to the troubleshooting thread.

Cheers,
George

 

Thanks for the links. I'll go ahead and and snap some photos and get back too you as soon as I can.

-groovin

 

Btw, I can keep the ground jumped right? That shouldn't matter as much as the 12v and would just be reinforcing a clean ground connection?

-groovin

 

Groovin,

Electrically, ground is ground. It shouldn't make a difference. However, I would remove the alternate path to ground because the tach is completely dependent upon the speedo board. This may prove useful when more troubleshooting is required.

Cheers,
George