k75 speed sensor circuit board components

[tbddkempf]

My board is damaged.  I need to replace the zener diode that is closest to the four female connections on the board, but I cannot read the numbers on the diode (corroded).  diode in question is marked with a red arrow on the photo I pulled from your site.
bmw circuit board 2 arrow.png (36.01 kB . 768x275 - viewed 530 times)

[kennybobby]

A 1N4148 might be a good option depending on how that part of the circuit is expected to operate.

[tbddkempf]

Fantastic help, thanks.  The other diode (green arrow) says "BZX55C9V".  Is this a good number,or is it obsolete?

[Laitch]

Fantastic help, thanks.  The other diode (green arrow) says "BZX55C9V".  Is this a good number,or is it obsolete?

Type the diode's identification number followed by the word "diode" after it in your browser's search window to find out.

[kennybobby]

Fantastic help, thanks.  The other diode (green arrow) says "BZX55C9V".  Is this a good number,or is it obsolete?

It is a good part number, e.g. digikey or mouser electronics.  That BZX55C9V is a zener diode that may be used as a voltage regulator, or in this case it might be used to clip the tops off or square up a sinusoidal pulse from a inductive pickup speed sensor. 

Can you desolder the red diode to read any marks or color codes?

They may be using the same zener diode in both places to act as a limiter on the peaks, both positive and negative going, from the speed sensor.

Really need to trace that circuit out to know what they are doing and what is needed.  A generic diode may not be a good solution now that i see they use a Zener in there.