MY brother had his K3 fail. He turned it on and everything came up
normally, but he could hear no signals or normal band noise on any band
but there was slight noise on 80 meters. Turns out the 8 volt regulator
had died. That is the one bolted to one of the side panels. If it quits,
the synthesizer dies with it. I did write up some notes about the
repair. (with pictures and arrows!) Changing out the regulator is
simple, but finding out that the regulator is bad took some PC board
sleuthing.
Dave K1WHS
On 6/22/2022 4:29 AM, Geert Jan de Groot wrote:
On 22/06/2022 02:50, elecraft-requ...@mailman.qth.net wrote:
With more K3 radios broken on the bench than working at my contest
station
(J68HZ) and NO spare modules to work with,
I am actually wondering about that. One of the magazines I read, the
German Funkamateur magazine, has a story each month about a group
doing some DXpedition and nearly every month they report about
equipment getting broken during such an event. As these things often
use Elecraft, there are reports of K3's failing.
But I wonder the failure mode because the stories don't report
anything about that. I know of a few failure modes:
- Diodes at input blown up because of extremely strong signals
near-frequency. Bandfilters may help, as does careful frequency
planning and some antenna distance. (ages ago I used a FT747 which
uses a light bulb as protection - after a heavy radio weekend I had
the lightbulb open and one of the input coils fused!)
- PA kickback causing the low-power amplifier transistors to fail -
there has been discussion on the list to add transzorb diodes
- Encoders for filter settings etc may fail - easy to replace
- volume knob was bumped on, causing potmeter broken - just replaced it
- Plastic knobs cracked - partially solved by Elecraft warranty,
partly solved by buying new ones myself ($$$$ with shipping and customs)
- Audio amplifier dying because of a short circuit at the output.
There is a mod kit for that.
I wonder about other failure modes. How does a K3 die at a contest
station, or a DXpedition, and what can be done to prevent?
What are the failures on the broken radios you are reporting about?
73,
Geert Jan PE1HZG
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