E30 speedometer woes

[kf martin <alteredbeast63@xxxxxxxxx>]

Id like to thank everyone who offered advice on how 
to get my '86 325es' speedometer working again; its
been a great help in isolating the problem.  

For the benefit of others who may go through this:

I started with the speed sensor in the differential,
first i checked the connectors - good.  I raised the
rear wheels, put an ohmmeter across the speed sensor
contacts and got a steady off/on signal as i rotated
the wheel; it switched every degree or so - good.  
so i went for the instrument panel itself...

I had previously confirmed that the batteries in the
SI board were fully charged and removed the corroded
led board (which brought my tach back to life!).  im
not really sure if a bad SI board can knock out the
speedo...ive heard both yes and no.  i had a number
of people tell me their experience with weld cracks
in speedo board itself...so thats what i looked for.  

It looked like my speedo board had been worked on 
by a previous owner...it was scratched and possibly 
re-soldered.  but ive tested every circuit board path
for continuity and unfortunately, found no breaks.

Im not sure what going on here, but im thinking that
some component on the speedo board could be shot...
and was wondering if anyone has a good speedometer 
to sell.  

Thanks,

Kurt Martin
SouthCentral PA
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