Hi,

I have a demo setup i am... or WAS... gonna demonstrate wednesday.
Now, the minute after i came back from lunch i heard a crack and a lod pop,=
 and when i got to my desk there was a small cloud rising from the demo=
 setup i had left running...

The cloud came from the power supply, a DIN rail Comatec 24V 800mA out. =
 Opening it revealed it had popped i=B4ts 35V output electrolytic.  So it=
 had probably been very high output voltage.  I found it had no crowbar=
 thingy at all.  Why do I buy crap??.  And of course i don=B4t want a new=
 such electrinics killer on the guarantee!

Anyway, it managed to kill almost all electronics, a PLC and a cirquit i=
 have made.

Now i have repaired my cricuit:

I had a 1N4002 series diode on input.  It hade *exploded* open.
After it there was a noise suppression choke, then 220uF 50V cap and 33V=
 1,4W (?) zener to GND.  The zener had short cirquited firmly, protecting my=
 design :)  What impresses me is that the zener was stronger than the=
 1N4002.=20
(what also impresses me is that the (madly running) 800mA supply (with only=
 470uF output cap) cracked the 1N4002 open...)   The Zener is a axial glass=
 Motorola 1N4752A.

To be wise i should also also have a fuse instead of relying on a "short=
 cirquit proof" tagged supply!

Now, i=B4ll dig into the PLC...

/Morgan

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