How to Troubleshoot an encoder

I have a Heindenhain Eencoder ERN 480 1024 IMPULSE.
The ECO servo drive fault number is F249 =" Check encoder and encoder cable"
Using my fluke meter I checked for cable continuity from one end to the other.
The cable have 8 wires.
How Can I test this encoder?
I'm also looking for a cable and encoder data sheet.
I searched on the net. But is not clear to me the 1Vpp 1024
Is there a direct replacement encoder that I can buy at McMaster catalog that I can use without without having to mess with the ECO servo drive?.
I thank you in advance for your help and education.

the simplest answer is "it depends". what is the output type?
according to this, it may be sin/cos:
http://www.auto-met.com/heidenhain/rotary_encoders/rotaryencoders/ERN/ERN400.htm

the easiest is to use an oscilloscope and look at outputs while slowly (really slowly) turning the shaft. if it is quadrature (pulse) encoder and this goes to plc high speed counter card, you can also look at the input LEDs.

I have used a scope to check an incremental encoder.
It checked out fine BUT if you put any perssure on the drive (It was belt driven) it stopped working!
Fixed with a new one!

If the ECOdrive is fitted with a Heidenhain, replace it with same. If you've tested the cable, that's about all you can do in the field. I'm guessing you could buy a special tester, but, at the end of the day, a replacement encoder is likely cheaper to buy, and likely the root of the problem. If you go down the 'couldn't I buy it cheaper from a catalog?' route, you'll also void the warranty of the drive, in case you didn't know that.

quadrature

if it is a quadrature encoder, you can use your Fluke and put it on Hz

Buying an encoder from a catalog is NEVER a good idea! If you want to ensure that you get the encoder that you need... not the encoder that you want... you should talk to an encoder supplier/manufacturer. They will be able to spec out an encoder that WILL work for your application.

One wouldn't go to a catalog to pick out a wife would they?

DON'T ANSWER THAT!!! lol

Never rule out the cable just cours you measured it.
Encoder cables are very fragile and sensitive for EMC and faulty grounding.