Resurrecting 3D Laser Scanner Need Help with Linear Encoder

[Pork]

So, I'm pretty much done resurrecting an old 3D laser scanner (Digibot II). I've pretty much repaired the mechanical and electrical problems but, now I'm at an impasse. One of the read heads for the X axis linear encoder is bad (the encoder uses a dual head setup for positioning the laser).

It's proving impossible to find a replacement so it looks like I'm going to have to repair or replace the read head/s myself.


Does anyone know of a compatible read head suitable to replace the bad one or would I be better off to depopulate the bad PCB, reverse engineer the trace, make a new PCB from scratch and repopulate it with new components?

Encoder Specifications:

Dynamic Research Corp.

LB2B-0032-BCR10Z234
LB = Factory Letters
2 = 1250 LPI
B = Accuracy Grade (see description)
0032 = travel length in inches
B = TTL compatible line driver (without cycle interpolation)
C = ZR Location is Center of Travel
R = right
10 = cable length (see note 3)
Z234 = Special requirements (see note 1)


Thanks

[ace1903]

There is not much that can be broken on that PCB. First check for dust and contamination of light source.
I have old heidenhain linear scales that are more than 30years old (from old NC machine).
Just cleaned carriage with ultrasound cleaner and put oil on bearings.
After cleaning check with scope outputs of LM393 then you will know if it is possible to fix this scale.

[Pork]

1. I've cleaned everything and oiled the bearings with a needle.

2. I believe the glass to be good as the other read head outputs a good square wave on both A and B channels.

3. The bad read head also outputs a square wave but the duty cycle is not 50/50.

4. When I attempt to home the laser the bad read head runs to the end of the x+ and acts like it can't find the end of its travel.

Perhaps I should start another thread and solicit some expert help in diagnosing the bad head before making another board.

Thanks for taking the time to reply.

[Pork]

I've started a new post dedicated just to troubleshooting the linear encoder.




Thanks