The manual says the opto-isolators are HCPL-2630s.

That datasheet is at http://www.fairchildsemi.com/pf/HC/HCPL-2630.html


Pins 1/2 are the anode/cathode of one LED.
Pins 4/3 are the anode/cathode of the second LED.

Get a DMM with current measurement.
Turn all power off and disconnect the leads that go to P1:4 , P1:2 , P1:3 ,=
 P1:5 and P1:6
( page 43 of 84 of the manual )
Get a good 5VDC supply.   Connect the 5VDC to P1:4 with the DMM current mea=
surement probes intervening.
Turn on the 5VDC supply and ground P1:2.   The DMM should show a current of=
  [ 5 - Vf ]/470  =3D=3D> 3.2 / 470 =3D=3D> ~ 7ma .
If you now reverse the leads of the good 5VDC power supply  ( ground now go=
es to P1:4 )  and apply 5VDC to P1:2 the DMM current should read zero since=
 the LED is reverse biased.

You can skype me at WFTelectronics if you wish.
99guspuppet
--=20
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