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Discussion Starter #1 (Edited)
Hi.. Anyone know where I can source a processor chip for the speedo preprocessor circuit board on a 16V 33 1.7ei. The preprocessor is the circuit board attached to the back of the tacho by the way. I believe that this same processor was also used on other Alfas of the era.
This is the processor




This is the circuit board with chip installed.
 

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Hi Ron

Here is part of the data sheet for that IC. It is a SAF 1091 by ITT.
SAF1091 Datasheet pdf - Speedometer and Mileage Indicator IC Kit - ITT Industries

Looks like it controls the scaling for wheel sizes and the like. This would mean that all those other resistors and capacitors are used in the configuration of the IC in setting the wheel size. There is likely a couple of formulas that dictate x ohm resistor with y pf capacitor equals the correct ratio for a 185/65 R15 tyre. Pity the data sheet is only an except and doesn't have the formula.

Unfortunately this would not be a part held by RS Online or the like.

If this is the fault, then it may be time to get a new board from a wrecked car.

Scott
 
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