Zener would have failed for a reason.
If you replace it most likely the new one will go that way too.
Peter
"Michael Kennedy" wrote in message
. ..
I was at the local surplus dealer and they had the zener diodes organized
by zener voltage. Would a 8v2 be a 8.2v zener?
Thats what I got and it seems to ohm very close to what the good zener
ohms.
The actual part number for the zener that I got is 1N5237b738.
Thanks for all the help Arfa
- Mike
"Arfa Daily" wrote in message
...
"Michael Kennedy" wrote in message
...
Is that black stripe a genuine paint one on the outside of the diode,
or a
Yes I believe it is genuine paint. It is on the other diode which has
not failed.. I guess I could find out what kind of zener diode it is by
testing it as you said, but I have never done this before.. I guess it
is time to learn.
Here is a picture of the working diode (ZD2 not ZD1) up close and in
the sun so you can really see the colors..
http://mikescomputers.homeip.net/LCD/DSC00386.JPG
Close-Up
http://mikescomputers.homeip.net/LCD/ZD2.JPG
Thanks,
- Mike
OK. Looks like a genuine paint band. I'm still up for it being 8V2
though, if for no other reason than it's a very common value, and
corresponds to the other two stripes. If what ever the unit is, is
working at all, then just check the voltage across the non-blown diode.
If the unit is not working, you can test the other diode for voltage
rating easily enough, by removing it from the board and hooking a
resistor - say 4k7 - to its cathode. Then put 12v across the combination,
"+" to the free end of the resistor, "-" to the diode's anode, then
measure the voltage across the diode. Any reading up to about 11v, will
be the zener voltage. If you get a reading of 11v or more, then the diode
hasn't 'zenered' and you need to up the voltage across the combination a
couple of volts at a time, until you do get a steady voltage, that
doesn't increase any more, as you continue to up the voltage. You've then
found the diode's zener voltage.
Arfa