Encoder type no is found as TS1508N66. Ii was found defective and replaced with type TS1508N76 which is equivalent. Now, G99 is functioning ok. But, the machine is functioning erratically with G71. In X axis it drops down fully instead of incremental drop. This machine has been down for quite some time.This problem is nothing to with encoder and it was there earlier. I will start a new thread for this. Thanks.[/SIZE]