Dear All,

I have an older machine which has been working fine over the years, maintenance is done frequently to avoid basic errors and mistakes, this machine has a Sinumerik 820 controller and the axis drive is a Simodrive 610 with 3 axis control. All of them use 1FT05 motors with the ROD encoder.
There was vacation time and the machine was off for about three weeks and when we got back and turned it on we noticed that the X axis was moving slightly as soon as the Enable sign was present. This does not happen in the other axes.
So I went to basics and altered the OFFSET potentiometer so that the motor came to a stop and it did.
When I was trying to move the axis manually with the CNC control, the motor goes to full speed and stops after a little while in an error state because it should run and when I let the key go it should stop.
I tried testing everything with a motor outside (I have another motor with encoder and cabling prepared) and the issue is the same. I disconnected the speed reference signal that comes from the CNC and as soon as the enable is present the motor starts moving very slowly when it should be stopped. I also changed the Power Card (Inverter Card) with a known good one and the issue is the same. No leds are lit in any of the boards either N1 or G0. The voltage levels seem to be within spec everywhere.
After all these tests I am guessing that it may be the N1 card with some sort of problem.
I would like your opinions as to some test I may do and have not done in order to further specify and discover the origin of the problem at hand.
Thank you very much in advance for your inputs.
Kindest regards from Portugal,

Luís