Richard Rasker wrote:
Joerg wrote:

Richard Rasker wrote:
Jan Panteltje wrote:

On a sunny day (Wed, 09 Sep 2009 20:55:49 +0200) it happened Richard
Rasker wrote in
et:

Jan Panteltje wrote:

On a sunny day (Wed, 09 Sep 2009 20:02:38 +0200) it happened Richard
Rasker wrote in
et:

So my question: is this a simple case of "bad luck", or are there
other ways a LED in an opto-isolator may fail in this weird way
(current OK, yet no light)?
Perhaps some part internal to the opto-isolater did break of due to
vibration and blocks the light path?
Did you open the defective one?
No, I didn't (yet) -- but isn't this very, very unlikely?

Richard Rasker
I could also imagine a bind wire coming lose of the photo transistor.
Before doing any destructive investigation, perhaps you could also check
the photo transistor.
Vbe and Vbc diodes, if it has the base on a pin, multimeter + on
collector, - on emittor, and feed the base from the collector via say
100k Ohm. Should draw some current.
The HCNR201 isn't a normal opto-coupler; it doesn't have one photo
transistor, but two photo diodes, one of which is normally used in a
feedback circuit driving the LED. Both photo diodes behave the same, i.e.
they don't respond to any current I send through the LED.

Somehow sounds like a busted LED.

BTW, it's best not to split groups and follow-up fields differently, it
mangles your thread.

Hm, I /did/ set the follow-up to sci.electronics.repair. I don't know what
went wrong ...


No, what I meant was don't post in two NGs and then set the follow-up
only to one. It splits the thread and also leads to double-efforts, like
someone answering while another poster had given the same answer in the
follow-up NG (which he hadn't subscribed to).

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.