Rebuilding/Repairing an Encoder

I had an encoder go bad on an LR-Mate (SRVO-138) resetting power did the trick for a couple of days, but by the time I found out about it, cycling power had no effect. Swapped the motor/encoder, did a single axis master, all is well.

But now I have a motor sitting on my desk with a big orange NFG sticker on it, and I'm wondering if it's worth getting into the encoder end. I did pull the cover off just to look, and nothing on the board looks smoked, there's no obvious damage to the rotor, and if I didn't know it was bad, you'd never know it was bad.

Anyone ever troubleshot one of these? Is there any point in even attempting to figure out what went, or trying to repair it?

The robot is 10 years old, but it's a clean environment and it's not a 24/7 operation.

It's not my money either way - I'm just hoping to learn something, and potentially put a motor on the shelf as a spare.

Thanks All!

I asked Fanuc about that when I was talking with them, and they apparently only sell these as a pair for the LR Mates. They're a Beta motor, so it's not like they're a fortune, but it would have definitely been nice to just have to swap the encoder.

Fanuc also doesn't service these, so if someone knows of a reliable group out there that does, or has a process for testing these, I'd be interested to hear about it.

Thanks!