[gbarrier]

Bretts gear looks very nice and would recommend it for anyone who may need one sometime in the future. While the gears are different the reset acts very similar on the 944 and the 968. After watching both for a while I have come to some conclusions. Can't imagine it hurting to reset while going down the road as long as it is a complete reset. Also I push and hold firmly for a second to be sure that the solenoid makes the full stroke. Then I do it once more. The second time the last digit seems to line up a little better. Can't imagine it mattering but it can't hurt to align everything very well before it stqrt turning again.

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[jmckeefery]

[quote name='Darryl' date='Jun 19 2006, 05:12 AM']James,



  I am all but convinced that this is electrical and there are a number of discussions about improved guage operation and the like after cleaning up ground points.  I also have the wacky temp guage that will right itself after a finger flick on the plastic dash screen just on top of the temp guage.  Bottom line is that I'm hoping cleaning grounds and checking solder joints will fix all these goofing dash/instrument problems.  - Darryl

[right][post="22977"]<{POST_SNAPBACK}>[/post][/right][/quote]



I had replaced all of the dash lamps back in 2000 but the illumination lamp for the water temp side of the dash board was out. A sharp rap on the plastic face plate would jar the lamp into working. This weekend I took it apart to fix that and install the gear. I cleaned the flex circuit traces that the lamp contacts ride on. I then powered the lamp circuit by a bench power supply. I have all of the shop manuals and the wiring diagrams for this car. There was a dead spot for this lamp in the fully installed position. I believe the lamp heat caused the white plastic behind the flex circuit to dent in a bit so that one spot was too thin to make good connection. The solution was to build up that area of the circuit trace with a little solder. It's tricky because the flex circuit material, and the plastic, can't take much heat, but all is well now and the lamp works fine. Wow! now I can tell my water temp at night.



I looked at all of the odometer wires and the soldiering on the PCB's looks good. My next move is to bring out wires from like 10 points on the circuit board for the stepper motor and drive the car around with a battery powered scope or LED indicators until I find where the signal stops. The stepper motor drive IC is a 16 pin DIP package so I should be able to get a part number off of that and find a data sheet to help in the debugging.



I will publish my results here so keep looking.



James

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[pickwick]

Today I fixed my odo with Brett's gear. My photos look much like sp4149's above so I won't post any. Eight screws for the oval bezel, four screws and three connectors for the panel, eight screws to remove the cluster from the black/clear cover, four to remove the speedometer unit, and two to remove the little motor to get to the broken gear.



I wasn't able to remove the panel w/o removing the steering wheel; I was having to pull too hard and didn't want to break anything else. So add two Torx screws and a connector to remove the airbag, a 24mm nut to remove the wheel, and four screws to remove the rectangular cover behind the wheel.



Was easier than I expected. And whoever said their voltmeter now reads higher: mine does too, by a good half volt.

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[Brett968]

I've been so busy at work I haven't had much time to check the forums. Just checking in and I see that a few of you have gotten your gears in. I'm glad it worked out! I am honestly surprised at the number of people that have needed these gears. When I originally designed the gear to fix the broken gear in my car, I thought I would make a full batch of gears since it didn't require much more effort to make 20. "That should last me awhile" I thought. I believe I am on the third batch now. I'm not really making money on them (I'm charging something so the wife doesn't give me grief) but I am glad I can offer something to the community.



Brett

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[sp4149]

[quote name='pickwick' date='Aug 27 2006, 02:24 PM']  And whoever said their voltmeter now reads higher:  mine does too, by a good half volt.

[right][post="25629"]<{POST_SNAPBACK}>[/post][/right][/quote]



I had the same voltage gain when I replaced the gear, evidently pulling out the dash cluster exercises the connectors and gives the same results as running new battery leads. Makes me think that the low voltage reading on the dash meter is due to oxidized connectors.



-sp4149

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[Anchorman]

THANK YOU BRETT, for the gear, and SP4149 for the photos. The amber gear had one tooth broken off, and the photos helped me do the job properly. Now I'm going to reinstall the instrument cluster and see if I screwed anything up.

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[Darryl]

Just replaced mine in the 944 and have the parts to do the 968...I too was worried about screwing something up in the instrument cluster upon re-assembly, but all went well. I also took the opportunity to apply a "fix" for the dash lighting which maintains the OEM state of the assembly...I hope to post pics on the other thread this evening. Here's a shot of my 944 broken gear. It was photographed exactly as it stopped as you can see when two teeth in a row break, even the vibration of whacking the dash won't allow the worm gear to grab back hold of it.



- Darryl

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[Anchorman]

ODOMETER WORKS!!! Thanks.

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[Allen1322]

Sorry to bring up an old thread, but I have some problems.

I have the same symptoms as jmckeefery, where my odometer will work for 1-2 miles (typically only when the weather is cold, or when the car is cold) and then stop. But when it does work, it 'clicks' through the numbers. So I thought it was the gear, bought a gear from Brett, and just now got around to replacing it.

Well the old gear looks perfectly fine, and I can spin the assembly smoothly with either gear in place. I don't want to seal everything up and put it back in the dash knowing that something is still wrong.



I think it is something to do with the stepper motor since the odometer will jerk when working. Does anyone know the fix for this? All soldering looks fine.



Also, if nobody has a fix, does anyone have a spare gauge cluster that I can steal from? any of you racers replacing your gauges?



Thanks,

A

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[happysails2you]

Since this thread was just revived....



I'm new to the forum, and see the issues with the trip and odometer. PO had the odometer repaired just before I bought the car, so it's working fine. I'd like to keep it that way. So what's the drill -- don't push the trip meter button while moving? Only push while stopped? Thanks!

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[Anchorman]

It certainly seems to be "don't push the trip meter button while moving." I've done more than one "push" when stopped, and that had no obvious negative effect.



Welcome to the forum and to the great experience of 968 ownership.

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[Allen1322]

Well, since I have everything opened up in front of me, I can say that there is no mechanical reason not to push the trip meter button while moving. I can spin the gears as if the car was in motion and reset the tripometer without anything binding up.

This COULD be a problem with the 944 odometers, but I don't see how this could cause problems with the 968. Someone probably decided that the reason their odometer stopped working was caused by pushing the tripometer button and then told someone else and they told someone else, etc. It's the old telephone game from elementary school. Either that, or it was a problem with the 944 gauges and everyone assumed it carried over to the 968.



I think I'm in need of an electrical guru for my problems right now.

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[flash]

i agree on your assessment of the push failure - i couldn't see the correlation either



check your multipin connections at the back of the cluster - i had an intermitent connection cause exactly what you are experiencing - looked seated, but wasn't



just to eliminate the pickup, does the speedo work?

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[Anchorman]

The "push" failure may be a myth - but I'm not going to tempt the failure. It's easy enough not to "push" while in motion.

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[jmckeefery]

I am working on it again this weekend. I have put a pair of LEDs on the two phases of the stepper motor and brought them out to where I can see them on the dash board as I drive for the last several months. The LEDs always flash, so the signal is not getting lost and the coils to the stepper motor are being driven, even when the odometer wheels do not move. Sometimes I can get 10 or 15 miles but it seems to be entirely random. My gear was fine, but I replaced it anyway, no help.



I pulled the dashboard instrument cluster again today and got a data sheet for that stepper driver IC.



This indicates that the stepping waveforms I see are normal for this design. It specifies that the on time is 37.5% for each phase, just what I see.



I powered up the whole speedometer / odometer system on the bench, and of course, everything works fine and I can't get it to fail. The speedometer is driven by the same chip, so if the signal gets small they both stop working at the same time. There is no way to have a low signal that stops the odometer and lets the speedometer continue to work. For reference, 80 mph on the speedometer requires a signal generator frequency of 145.36 Hz. One thing of note is that the odometer stepper motor gets quite warm, 20 degrees above ambient, not too bad. I even tested the odometer down to a battery voltage of 6V and it ran fine. The speedometer fell off in accuracy at 10 Volts battery



All of this bench testing is putting miles on my car!



I did sand some mold flask off of the replacement gear and reinstalled it, that may help.



I sanded and re-tinned the tips of the 4 pins that electrically connect to the speedometer / odometer module. But as I said if the speedometer works, the odometer must work, and my LEDs have always worked.



I also replaced the three wires from the motor driver PCB to the Stepper motor PCB, maybe that will help.



I road tested the car and all was well for about 2 miles then I stopped and reset the count. It has not started again from that point on.



So I am kind of sick of this problem for now. I just put it all back together and will just drive it without a functional odometer for awhile longer.



At this point I believe it to be mechanical. The stepper motor just seizes up. Replacing the speedometer module or just the stepper motor itself should fix the problem.



Let me know if you find a good source for either of those.



If you will send me an email to Jmckeefery@aol.com then I can send you some photos of what I changed. The speedometer / odometer IC data sheet in attached.



James McKeefery

408-946-8550

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[Allen1322]

Flash: The speedo does work. I thought i mentioned that somewhere?



jmckeefery:

Thanks for sharing your progress and findings. I was hoping to get this figured out before stuffing the gauges back in. It was such a pain getting them out, I wanted to be 100% sure everything was going to work before putting them back in.

I guess I'll just grease all the gears up good, check all my connections and grounds, and hope for the best.



If nothing else, I had a chance to correct for some of the mileage while the gauge was out. I felt bad about driving 5k miles and the gauge not reflecting it. I ended up using a drill to wind the gauge forward.



-Allen

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[Mhmara]

Any other cheap places to find the gear. The last place was a bit expensive that was on line. Anyone got them cheap?

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[banditsc]

[quote name='MikeH' post='39040' date='Jul 29 2007, 08:13 AM']Any other cheap places to find the gear. The last place was a bit expensive that was on line. Anyone got them cheap?[/quote]



www.odometergears.com

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[Darryl]

+1 on odometergears.com. Jeff is fantastic.



- Darryl

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[Mhmara]

I would have to agree. I ordered the wrong gear (miss click) and he took good care of me. He also said there is no issue with resetting the trip meter while driving.

[quote name='Darryl' post='39044' date='Jul 29 2007, 07:30 AM']+1 on odometergears.com. Jeff is fantastic.



- Darryl[/quote]

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