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Discussion Starter #1
My odometer has stopped working. The speedo works fine so I'm presuming either the mechanism has packed in inside the dial or it has a separate drive. I seem to remember that the speedo is fed by pulses so is the odometer cable fed? There is an S4 cable on Classic Alfa. Anyone shed any light? Thanks in advance.

EN089 SPIDER SERIES 4 SPEEDO CABLE (AND SERIES 3 1988 ON) - Classic Alfa
 

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Discussion Starter #3

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As per that other post, the original odometer on my manual car stopped working so I eventually replaced the speedo with a spare unit, similar mileage.

Cluster repairs had said they couldn't source a replacement chip so sent it back without repairing it. I have since found a replacement chip by searching using the code on the old one but haven't got round to replacing it - I don't have the soldering skills so will have to take it to someone who does.

Luckily this chip doesn't need any programming, whereas the other one has the coding to interpret the signals and translate as required.

When I am back home I will post the code for the chip, in case that is your problem although I don't know how you would test it at home. The chip is only a few quid so maybe the answer would be to just get one and try it?
 

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Nick were these the chips you sourced?
1.7ei Speedo problems Need parts - Alfa Romeo Bulletin Board & Forums

afaik, the speedo in our cars has two IC chips, SAF 1090 and SAF 1091

don'T really understand all of this stuff myself, but I guess someone might find it interesting reading!
EDIT: reliable source has informed me that this datasheet doesn't pertain to the alfa instruments.
 

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Discussion Starter #7
Yes, those are the ones Dom. The odometer one is SAF1091.

I sourced it from LittleDiode - Electronic Components Supplier

It was a bit more than I thought; ca. £16 inc. VAT and P&P.
Thanks for this Nick and everyone else for the useful advice. I will remove it at the weekend and see if the cog has gone and then, as you say, change the chip. It it easy to see the cog once removed?
 

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Discussion Starter #8
Couldn't wait until weekend so just taken it out and managed to remove the speedo element from the pod. The cogs I can see all seem ok, but where is the chip. Is it under the circuit board on the back of the speedo? Thanks.....
 

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Yes, it is. There is one near the edge, under the motor for the speedo (which has the green and the red wires going to it) and the other is nearer the centre.
If you take the four rubber feet off you can bend the circuit board down a bit to take a peek, but the board is held on to the unit by two wires which would have to be unsoldered to get at it properly.
 

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Discussion Starter #10
Yes, it is. There is one near the edge, under the motor for the speedo (which has the green and the red wires going to it) and the other is nearer the centre.
If you take the four rubber feet off you can bend the circuit board down a bit to take a peek, but the board is held on to the unit by two wires which would have to be unsoldered to get at it properly.
How do the four rubber feet come off and which is the chip for the odometer. To be honest if this involves soldering something back into the circuit board I think that's me out! It may not even be that anyway and there's no way to test. No used ones around either!

If I get the chip is there anyone who could repair it you know of?

Thanks!
 

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The rubber feet just pull off. Well they do on all the ones I have looked at...

Someone like Cluster repairs or Speedy Cables would look at it and hopefully be able to tell you what the fault is. If it is the chip then they would be able to replace it.

I can't remember whether it is the central chip or the one near the edge of the board.
 

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Couldn't wait until weekend so just taken it out and managed to remove the speedo element from the pod. The cogs I can see all seem ok, but where is the chip. Is it under the circuit board on the back of the speedo? Thanks.....
if you do this repair yourself, could you take a few photos...pleeeze;)
 

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Discussion Starter #13
The rubber feet just pull off. Well they do on all the ones I have looked at...

Someone like Cluster repairs or Speedy Cables would look at it and hopefully be able to tell you what the fault is. If it is the chip then they would be able to replace it.

I can't remember whether it is the central chip or the one near the edge of the board.
Many thanks, I'll have a look and if I'm not brave enough, I'll give them a call! Dom, if I have a go I will be sure to take photos.....
 

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Discussion Starter #14
It's working! The problem is, I'm not entirely sure how I did it!

The only thing I think it could be is that I could see a small white cog behind what I think is the motor driving the odometer barrels and it locates into a set of teeth fixed to the side of the speedo unit. Using a magnifying glass, it looked like maybe it wasn't located properly, but it was difficult to see. Anway, I undid the two screws holding the motor in place and withdrew it. The cog looked ok.

I then pushed it back in but it would not locate at first as the teeth were not lined up so with bit of trial and error, rotating the cog slightly, it seemed go in with a slight click. Having screwed the motor back, the cog looked to be located properly.

So, I put it all back together and fitted it back in the car and hey presto, it works!

I will post some photos of the motor and cog in a day or two when I get them of the camera and size them up.
 

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Brilliant! Well done Tom. I will have another look at the one that I was told had a chip problem - maybe it is a cog issue too.
 

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Discussion Starter #16
Brilliant! Well done Tom. I will have another look at the one that I was told had a chip problem - maybe it is a cog issue too.
Worth having a look Nick, however, I have a slight problem now with mine! Odometer and speedo are working but the speedo is indicating around 10mph under!

I can only presume that the small cog I rotated slightly to get the teeth to line up must regulate the speedo, but I don't know how or why. I will have to take it out again and turn it slightly but not sure in which direction. It is going to be a right pain, trial and error and in and out of the car! Unless any one on here knows more than I do about how the speedo is regulated?
 

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Discussion Starter #17
It's ok Nick I searched and found your link to AlfaBB on how to adjust. I guess I must have disturbed it when messing about with it, unless turning the cog did it and it should be recalibrated? Could you please talk me through how you adjusted it in car. Thanks!
 

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Looking at the speedo I have on my desk, I would have thought that the cogs are for the odometer and don't impact on the speedo. Maybe you disturbed the potentiometer that calibrates the speed?

As you have found the other link I guess you know where the potentiometer is, and that you can turn it with a small screwdriver so I won't go over that again.

I ran the speedo separately from the instrument panel by connecting up power, ground and signal to the back, using a small terminal block as a plug, terminals as per photo. The "pins" to go into the speedo are short bits of paperclip. You can see one in the block in the photo below.
I have made up a power/ground feed from a spare plug that goes into the lighter socket, with a couple of wires soldered in but you can connect to anywhere you know there is power and ground.
The signal feed is a long wire connected to the wire that feeds into the plug at the back of the cluster. On my automatic car it is a grey wire going into the plug with four wires. I can't be sure it is the same for yours but you can trace it on the circuit board if you don't know.

Having hooked it up, have your lovely young assistant hold it whilst you drive at a nice steady speed as shown on your TomTom or whatever, and then get her to tweak the potentiomer until you get the speedo where you want it.

It all sounds more complicated than it is in practice,and it is so much easier than putting the speedo back into the cluster and taking it out multiple times for trial and error.

 

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Discussion Starter #19
Thanks for the detailed description Nick. Nice idea using terminal block as a 'plug'. I'll give it a go, much better than trial and error! I remember seeing the potentiometer when I had it out, as yiou say, I must have disturbed it. I'll report back.
 

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I tried your fix on the speedo I have with the non-functioning odometer last night. I see what you mean about the little click when you relocate the motor and I got excited thinking that it might have done the trick. Sadly not, though. When I bench tested it the odo was still not working so it probably is the chip.

Incidentally, as well as this one I do have two other spare speedos; one from my parts car with ca. 23,000 showing (it had been a replacement) and a NOS with zero miles. I will keep the latter but if anyone is after a replacement speedo I really don't think I need two spares in addition to the no-go odo one.
 
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