All right.
It is a fraction collector, Frac-100. Made by Pharmacia, Uppsala, Sweden.  There is no schematics in documentation.
I traced a little the circuitboard. So, there are 2 bridge rectifiers after transformer. One gives 10 and the other one 20V DC. +10V go to voltage regulator and become +5V (it is used fo TTL), between those 5V and -20V this diode and 1W resistor (as a voltage divider) are placed.  20V are used to operate a stepping motor (it activates by the 20V saw shape signal).
That is basically everithing I could gather.
Thank you for your efforts.
Sincerely
Boris
 

On a board it is marked as a diode (i.e. V102 or something like that).
By itself it looks like a diode, 1/8'' small cilinder, the simbols are written across it, as follows
C
10
301
and at the end there is a Motorola sign
M (a kind of 2 arrow tips pointing upward)
it has ~+10V on cathode and ~-20V on anode

Hi there
Could anyone help me out. I need to replace a diode but I can not identify it. It says on it C10 301, and it is Motorola. I would greatly appreciate any info on it.
BG

Hi there
Could you help me out. I need to replace a diode but I can not identify it. It says on it C10 301, and it is Motorola. I would greatly appreciate any infor on it.
BG