On 2011-09-16 2:48 PM, whit3rd wrote:

The most common item that one sees in a switching supply
next to an optoisolator is a TL431 programmable zener
(actually a voltage reference/error amplifier combination).
Possibly that's what you have, they're multiple-sourced
in LOTS of package styles.

Yep, I think that's probably it! Thanks! (Also see my
reply to "Franc Zabkar". I saw his reply first. He
mentioned the Hitachi version of 431, 432.)

--
Cheers,
Robbie Hatley
Stanton, CA, USA
lonewolf (at) well (dot) com
http://www.well.com/user/lonewolf/