On Tue, 18 May 2021 23:17:32 +0100, T i m wrote:

On Tue, 18 May 2021 16:03:31 -0400, legg wrote:

snip
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So are we still on for replacing the opto device RL? I don't think my
tester can do that, other than the opto side as a diode possibly and
if it wasn't so cheap and already fairly old, I'd set up a test for it
myself on some breadboard. ;-)

Optos get leaky, light seals break. - in most feedback loops that
means it's turning the circuit off without assistance from the TL431.


Just to give me a better visualisation on all this, could you point me
to a schematic of something similar perchance please?

Cheers, T i m

https://www.power.com/design-support...gn-methodology

You'd probably get better app notes chasing down the actual
part number in the unit.

RL