Problem- g320 running with fault light ?

[rokag3]

I have 3 g320 i was working with a home positioning and i discover that my gecko was not going reverse. Since this gecko was using for many test i thought that the photocoupler was dead. I take my courage an took off the gecko out open it and change the opto then put it back on.
As soon as i put the power the servo start to turn THEN the fault light turn on but the gecko did not stop and running almost full speed.
Normally if the g320 do not stop it's because the encoder is not plug in I check the encoder work perfect. I make the test of 1 and 3 and4 and 2 and 3 and 4 they looks ok so maybe my g320 is not fry hope so because i took a second g320 and it make the same thing. I am waiting before using the 3rd one
any idea ?
what shoud i test ?
encoder amt 120 servo keiling 72V

[lavrgs]

You should test it without the motor hooked up. Make sure the encoders are working properly. test A then B vs. gnd while turning the motor slowly. It should change from ~ 0VDC to ~5vdc.
I really hate Phoenix connectors - connectors are usually the weakest link but with the phoenix there's often no link. I'm going to start tinning the wires before making the connections.