Hi , please help me to identify crystal and zener . This board is electro mechanical hour counter of excavator . Input is 12V DC . zener voltage on board is 12V

 

 

 

 

If you clean up the crystal, it may have its frequency stamped on it somewhere. There is also enough lead left on the crystal to put it in a simple oscillator circuit and measure its frequency.

What brand and model is it? Someone here may have a shop manuals related to it.

 

not enough lead on crystal . Also just "9AI"marked extant on crystal . Could this be a clock crystal with 3.2768 Mhz frequency?

 

There was a zener diode in the board that burned . I measure voltage and is 12V . what diod to replace

 

I suspect it is a clock crystal. Question is frequency. It could be any power of 2, like 65536 Hz too.