I found a small DC motor at the dump with an optical encoder on it. I'd
like to be able to use it, but I have no specs on the encoder. It's a
Rae Corp motor, but the sticker is stamped "Aug 27 1976", so I have no
hope of finding specs for it.

There are 2 micro ckt bds, but glued in place so ckt tracing is out. I
can see 2 emitter/sensor pairs & there are 4 wires. My best guess is
that the ckt looks like this:


Blk Y Blue
| | |
+-+--+ | |
| | | |
+++ +++ +++ +++ Photo
LEDs | | | | | | | | Detectors
| | | | | | | |
+++ +++ +++ +++
| | | |
|____|_________|_____|
|
|
|
R

(based upon using a VOM & seeing that Y-Blue = Y-R + R-Blue). The LED
pair is 600k in 1 direction & 1.8M in the other. The detectors are
about 2k in both directions. There are also 4 resistors: 2 fixed & 2
trim. Does this make sense? In particular, does it make sense that the
detectors would have the same resistance in both directions?

Then, how would I hook it up?
- voltage to apply to Blk (LEDs)?
- a resistor on each of Y & Blue in series to voltage, signal taken at Y
& Blue?
- if so, voltage & resistance values?

Thanks,
Bob

--
Nota for President