Speedometer circuit board diagram needed

[Rick Z]

Hi all. Does anybody know anything about the speedometer circuit board from an '85 535i? My speedo and odo stopped working after a long layoff for engine work - tach and mpg gauge work fine and diff sensor checks OK. I've taken the instrument cluster apart and the speedo board off the back of the gauge - there is a resistor that has burned black and I suspect it is the cause of the problem. It comes from the +12 supply. I happened to find on another BMW forum (e30) someone who had the pdf info on the IC chip (it's a UAF2115 that is commonly used for speedos and tachs). The problem is that I can't tell what value the burnt resistor is so I need a schematic diagram of the circuit. The part number on the board is 92 644 696 (it might be 992 644 696). Any ideas? Thanks.
Rick Z

[ROYinGA]

Is that the supply you're tracing? My car is earlier and a Euro. Sorry.

[ROYinGA]

small speedo oard?

[fabrice002]

has an exemplary circuit with component values that is almost exactly what VDO designed.

Don't understand why you still have MPG... that relies on the electronic output from the chip that the pdf also shows.

FWIW, my iX speedo was intermittent, but was two reasons: the pulse sender in the diff, and a bad solder joint on the integrating capacitor.

A burned resistor is usually an effect of a problem, not the cause.

[PaulR]

Just in case you still need this (and an E30 gauge view helps you), I had my '85 325e speedo opened up last week to change SI board batteries and found that the a resistor had been burned also. My resistor was a 33-ohm.

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http://mydrive.roadfly.com/photos/pic.php?u=73302r2fUS&i=14555 (solder side view)
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