Let me throw in an experience here that may save someone else a little
confusion. When I built my KPA100 the kit was complete EXCEPT for one half
of the fuse holder. I was building it over a Thanksgiving weekend so I
didn't even consider calling Aptos for the part. I just hopped down to the
local automotive parts store and grabbed a similar fuse holder that even
came equipped with a 20 amp fuse!
It worked FB, for several weeks...
One evening in the middle of a QSO, power to the K2 died for an instant,
then came back on. Hmmm... My big linear Astron is sitting under the table
so I didn't seen the meters on it wiggle. A few minutes later, during a QSO,
it happened again, then again. Lights blinking, relays reinitializing,
scrrich, scrrich...
Hooked up a dummy load and started sending with one eye on the Astron meters
and sure 'nuf, it happened again, only the voltmeter on the power supply
didn't budge. Just the current jumped all over the place. Connections at the
back of the Astron were tight, as was the Anderson Powerpole connector at
the K2. Then I happened to touch the fuse holder. It was HOT!
The auto-store fuse holder and fuse was getting quite warm without blowing
the fuse even though the peak current was about 15 amps or so. I surmise it
was due to cheap contacts. A little resistance where they pressed against
the ends of the fuse produced significant heat. That, coupled with cheap
plastic that was softening when warm was causing the problem. The whole fuse
holder was actually stretching under pressure from the contact spring from
the warm temperature until the spring was no longer holding good pressure on
the fuse and the contact became really intermittent.
Bought a better holder and have had not trouble since. Its been several
years now.
The moral of the story, "All 20-amp in-line fuse holders are NOT created
equal..."
Ron AC7AC
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