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-   -   Odometer still not working! (http://www.classic-audi.co.uk/forum/showthread.php?t=36347)

Gmac 21-12-16 06:48 AM

Odometer still not working!
 
Morning all!!!

Went out for the test drive yesterday and the odo and trip are still not working!!

SO I quickly took the cluster out again, took it apart and swapped the tiny cog that (that I replaced) and flipped it. I couldn't be sure which way it came off. Although pretty sure I had I correct the first time. All back together and out for another test drive, no difference!

I did however get the speedo needle put back on so that it reads the correct speed.

So now I'm a bit flummoxed. Here's where I need your help!

A few observations... Comparing the odometer gears.com Audi pdf...

My cluster looks slightly different on the back...my big black box is white on their example.

Also on their example they talk about removing the small circuit board and the wiring, which again mine doesn't have! Not too sure what it's for?? Something perhaps about an onboard trip computer. I believe they are using a cq cluster.

Pics of the differences...
Mine..
http://i1169.photobucket.com/albums/...d.jpg~original

Theirs...
http://i1169.photobucket.com/albums/...8.jpg~original

The small circuit board...
http://i1169.photobucket.com/albums/...h.jpg~original

So now on to what I'd like to do...

I'd like to test the small motor that makes the gears spin as I can't see anything obviously wrong with the new wee cog and the setup of the original cogs, they all seem to mesh together correctly.

So how do I go about putting power on to this to see if the cogs are spinning at all???

Pic of the small motor setup....
http://i1169.photobucket.com/albums/...g.jpg~original

slacky 21-12-16 08:05 AM

Sorry to hear it's not working, not looked at mine yet , might have a go over Christmas,
just to recap , your original cog was damaged is that correct?, if so it seems weird that a new undamaged cog has made no difference to anything, as it must have been doing something, very confusing, then again that's not hard for me ;)

Gmac 21-12-16 08:12 AM

Original cog was damaged yes, but that could have just been one of perhaps a coupe of things wrong. Which it now does look to be the case..

Old and new..

http://i1169.photobucket.com/albums/...m.jpg~original

chalkyh 21-12-16 09:59 AM

My 90 20V sport had a similar issue - but the small gear was ok. Traced to a hairline break on a soldered connection on that small board - looks like heat cycling from that little motor caused it.

Hanuman 21-12-16 10:46 AM

If it's anything like the ur...

The Odometer is driven by a small motor. I think it's a stepper motor.
There is an IC (black, oblong device, 8, 10, or 12 legs, possibly) which will provide a signal to the motor. It should not be too far away.

On WR's, I've seen plenty burned out, with damage to the board. Some with signs of heat in the middle of the IC body, others with cracks. Scorching, sooty marks.
Also the other components like resistors and capacitors which form part of the circuit.

If you have none of that-
I would have a careful look at the solder joints. The old issue of dry joints on devices and connectors.

Also. Capacitors have proven to be the source of some problems before, in some of my cars.

sinbin5t 21-12-16 01:05 PM

Mine has that little circuit board ( V6 engine ), but the clocks i got from a 7A engined car 3 years older approx doesn't :confused:

Strange eh !

Gmac 21-12-16 01:09 PM

Thanks for the replies folks...

I'll whip the thing out again and take a closer look at the soldering for any cracks, discolour etc.

Here's a pic of the whole circuit board that has the motor on it.

http://i1169.photobucket.com/albums/...v.jpg~original

Mark...do you mean these 4 pins coming off it on the bottom right?? What does IC stand for? Haha, I can feel a whole engine temp gauge ala the ur coming on here with my electrical skills!! Haha

Would like to think I can get power to the motor to see what it's doing.

Hanuman 21-12-16 02:38 PM

Sorry.

IC. Integrated circuit. The black multi leg gizmo. Different ICs for diffent things.

That type of board is quite prone to bad joints over time. The 4 pins are just a simple connector, and could also be prone to bad connections.

2 decades plus, old electrics.
It would be interesting to see the solder side of that board

Gmac 21-12-16 03:53 PM

Haha, anticipated that so I've pull it apart, again!!!, only took about five minutes now!, and here are the two sides of the board...

Have to say, can't see anything obvious.. Nothing burnt out... And without getting too much down in the weeds, how am I going to supply power to the motor to see if the cogs are spinning as they should?

http://i1169.photobucket.com/albums/...b.jpg~original

http://i1169.photobucket.com/albums/...3.jpg~original

audi80fan 21-12-16 04:08 PM

I admire your determination, fortunately for me a had a full spare set of clocks with working everything and it certainly made my life easier! At some point i will need to swap over the speedo from the old one as mileage incorrect but in no major rush.

Could you not pick up a spare set cheap enough? Replace the full unit


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