Hi all,

I need help identifying a 'broken' diode on a BL2-D drive. The diode has no markings.

I have an OKUMA LB35II with a '1008-11 SVP DIFF over X-axis' error. The axis will give this error even in manual mode, from about 3 to 3mm on going UP. On going down there is no error.
With the suggestions on another thread I located the error to the BL2-D drive.
I changed the UX, VX and WX with UZ, VZ and WZ on the BLII-D drive and, unlike the suggestion on the referred thread, also the INPUT on the SPV board (the cables coming from the respective encoders X and Z). Note that the X on the controller now moves Z and vice-versa. This resulted on the error passing to the Z axis, meaning the problem is on the control of the X axis.

Luckily we have another machine with an OSP7000 control and same SPV and BL2-D boards so we were able to exchange these boards individually and locate the error to the BL2-D board.
With same idea in mind, since the BL2-D is composed of a control board and a power board, we also switched them between the two units we have and located the error to the control board (SVCII).

Finally while looking for the damage component we tested two 12V relays (DSP1a AGP2003). One worked correctly, the other was shorted. They each have a diode in parallel and the one on the failing relay lid up on initial tests so I removed it. The relay now opens and closes correctly so the diode must be the problem (or one of them at least).

So the only thing missing is replacing the diode (I hope) but this one is not easy to identify. It has no markings!
So I ask if anyone can help me identify it.
I attach a photo of the diode.
Its approximately 2,5mm long by 1,75 diameter.

I also removed the working one and tested it.
I put it in series with a 220ohm resistance and an unregulated (finished this at home...) 12V power supply. Plugging the '12V' power supply only to the resistance I measured 15,15V.
Plugging the power supply to the diode in series with the resistor I measured 18,05V across the diode and 0V across the resistor, and no current. Changing polarity had the same results.

Any help?