Classic thinking Dale !.....zeners usually have a resistor in series to determine the current.....it must have taken excess current to smoke.........that generally can't come though the resistor (they normally go open not short) so where else could the excess current come from. Then apply a meter to check that theory.
This is the most fun part of repairing stuff......oh yeah it can also be the most frustrating.!
Stuff that jus'works is nice but boring :-))
Alan
G3NYK
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----- Original Message -----
From: "'Dale H. Cook' bridgewaterma@... [hp_agilent_equipment]" <hp_agilent_equipment@...>
To: <hp_agilent_equipment@...>
Sent: Monday, February 08, 2016 10:20 PM
Subject: Re: [hp_agilent_equipment] Looking for a replacement part for HP 721A
At 04:31 PM 2/8/2016, Paul K wrote:
I am trying to find a suitable substitute, or the specifications for the CR7, in an HP721A power supply.
Later production calls for an HP 1902-0190 7.5 volt +/- 5% Zener for CR7.
The blue smoke came out of the diode, and I want to put it back in.
You will very likely smoke the replacement unless you first determine and repair the cause of the diode failure.
Dale H. Cook, GR / HP Collector, Roanoke/Lynchburg, VA
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Posted by: "Dale H. Cook" <bridgewaterma@...>
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