Need Help!- Alarm 16/20 with Mitsubishi MR-J2-100a

[AFAIK]

I bought 2 Mitsubishi MR-J2-100a servo drives from eBay a long time ago but I didn't have any servo by Mitsubishi for testing them. I have now got a Mitsubishi HC-SF202b servo motor (I know the motor is twice the power the drive can provide) and have connected everything up to the drive. I get alarm 16 and sometimes 20 as soon as I turn the drive on and it wont go even if I try to clear or reset it using the PC software.

To me, the odd bit is when I turn the shaft I can see the number of pulses and the rpm change correctly on the computer. My encoder has 10 wires coming from it and the manual says there should be nine, all nine that are meant to be there I have wired up but I don't know what the tenth wire is meant to connect to if anything. The tenth wire is connected to the 'm' pin on the encoder socket.

So, does anyone know what the tenth wire is there for and if there is anything else I can do to try and fix or find out more info from the drive?

[Al_The_Man]

Page 3-19 of the manual does not show anything to this pin?
http://www.meau.com/Files/SH_NA_3181-L.PDF
Al.

[AFAIK]

I have been through those pages and the whole PDF but I didn't see anything mentioning any extra pins and the wiring section is the same as the drive manual.

[AFAIK]

I have looked in the alarm history on the drive and before the encoder alarms there is alarm 32 which is over-current I also checked the 5v rail to the encoder and it is 4.76volts is that too low for it to work properly? And could Over-current have caused the damage if it isn't normal?