Winding Back a Speedo............

[Beatle]

I know, I know,............ sounds dodgy.

I have an LCD instrument panel in my Alfa 90.  Car has 117,000km (shows as 17,000 on the five digit display).   I want to install the analogue panel from the later Super model in place of the LCD dash but the panel I have shows 230,000km (six digit).   The replacement odo/speedo is still electronically driven, not mechanical cable.

How would one go about winding the new speedo back to the correct vehicle mileage?   I assume there is some sort of anti-tamper booby trap installed?  Or is it simply telltale wafer seals on the joins on the back of the instrument?

[colcol]

I have fixed Speedos in Alfa Romeo's, Volkswagon's, various Holdens and the odometers were all the same!, as it is something that is very generic in all the cars.
Last year my 33 speedo was playing up, so i purchased another one from a wrecker.... and i had to wind the 'new' one back from about 500,000 to about 280,000, so that all my servicing  would still all make sense and be on schedule.
You pull the speedo apart, and the odometer numbers roll on a about 3mm pin, i just knocked the pin through with a drill of the same size, took the numbers out, rotated the numbers so that they were correct with the old speedo, put the numbers back on the pin and knocked it through.
The speedo and odometer don't have a cable, they work or don't work electronically, with a series of blips coming from the phonic wheel and pickup in the gearbox that drives a stepper motor, or at least thats the theory.
There was no booby trap or anti tamper method on the 33, it was a Jaegar Speedo, ...with the usual reliability you would get from a Renault, Colin.

[Beatle]

Thanks Colin, the 90 Super dials are also Jaeger.

I'll delve.....