[Elecraft] Stupid, stupid, stupid - OT - NIR-12 troubleshooting

[James C. Hall, MD]

Well, I must humbly submit my most recent gaff. It's nothing like landing
long on a short runway (yikes!), but it relates to my inquiry on
troubleshooting my JPS NIR-12. 

For several days now, Don W3FPR has been trying to help me figure out why
power was not being applied to this unit. It was thought to be a bad diode
running in series in the 12 volt line. Why was I getting 13 volts on the
anode and virtually no volts on the cathode side. It was as if there was no
ground on the cathode side of the circuit. I tried shorting the diode which
made an impressive smoke job of an electrolytic capacitor shunting to
ground.

Well then I retraced my steps. I discovered that when I pulled the unit out
of the shelf, the Radio Shack modular power plug (which goes to a 'wall
wart') came off the 2-prong saddle on the wire. I merely plugged it back in
the saddle. The AHAH moment came when I checked the polarity of the plug - I
had accidentally reversed the polarity of this plug (VERY easy to do with
these modular plugs). The diode was simply doing what it was designed to do
- protect the unit against dumb things like this.

In the immortal word of Homer Simpson - D'oh !!!

Don, thanks for being SOooooo patient with me !!!

73, Jamie
WB4YDL
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