Red lights on amp, is it dead?

[smithgrind]

I've got a red light on the amp for my 4th axis, amp 0006. It's a dc amp on an AC machine so I can't swap it around. I had a tech in for a problem for a different machine, and he just said it's bad, without checking anything else other than looking at the red light. Is this usually the case? What can I test to verify it's definately bad before shelling out $700 for a used one?

[mniadna]

I was wondering the same thing... I have a machine with DC servos. I have a DC 4th axis amp and it has the light on. I don't have a rotary table. I was assuming it was on because there was no feedback from the servo and resolver...

[iess525]

It could be bad amp, I can help to find out please call me on 8186789546

[alex gitzel]

There is a glass fuse on the amp chassis and on some of the amps there is also a small glass fuse on the bottom of the amp,check these first(power down and remove them and ohm them,they may look and ohm ok in the machine but still be blown).then you should ohm the amp to plug,and plug to motor harnesses,then ohm the motor out (around 1 ohm leg to leg and nothing to ground) and look over the resolver.The amps usually do not just go out with out a short somewhere,but it can happen.With the red light on the amp is most likely done for,but the motor or harness can cause it.if everything else looks ok swap the amp,when running the rotary make sure the motor is not getting hot,like the air brake is draging from water/rust in the air line.the amp will have a red light if the dummy plug is in when the rotary is off the machine.

[mniadna]

alex,
Thanks for the info. My dummy plug is in.