@zulfiqaralichaudry, when I enquired as to the voltage at the coil, I meant for you to measure the voltage with respect to ground, not between the coil's terminals.

As for the diode, if you selected a replacement merely on the basis of package style or dimensions, then you were extremely lucky. Diodes vary widely in function, irrespective of package style. Your original diode was a high speed Schottky diode whereas the replacement could have been anything.

Furthermore, if D9 were open circuit, as your measurements would suggest, then I would have expected that the coil would have produced a destructive back EMF (several hundred volts) whenever its current was interrupted. This would normally have killed the adjacent MOSFET, so I find that extremely puzzling. The diode's function is to provide a path for the decaying coil current.

Anyway, all's well that ends well. Congratulations.

_________________
A backup a day keeps DR away.

fzabkar, thx a lot.

May be you have not copied all the data from hard disk properly.