Kaoming ATC Tool Changer Homing Issue

Hello,

I am not sure if it is the correct place to post a thread about a hardware issue here, sorry if its not. I have a 2005 Kao Ming SD2000 double column vertical machining center with Fanuc 18 iMB control. Last Friday it stopped changing tools. When I turn off and on the machine we send it to auto-reference as usual, however the atc does not go to it's home position (I got that from the atc home pos. light doesn't lid). When I try to change a tool using Txx M6 command, the machine simply freezes with no action nor error message. I suspect that there is an issue with a switch in atc, but each time it stops at tool #1 as usual. Perhaps there is a problem with parameters that control tool change, but I got nothing but more confused after I looked at Fanuc's brain-grinding manual.
Any ideas? Thank you.

Sadettin