[Elecraft] KAT100 Troubleshooting

[Don Wilhelm]

Rolf,

The display of 20 watts is correct - the firmware limits the KPA100 
power to 20 watts when tuning at high power.

The fact that it appears not to complete the TUNE is a potential 
problem, but if you have replaced the diodes in the KAT100 and they are 
still good, *and* it tunes correctly at 10 watts, then I do not believe 
the problem is in the K2, KPA100 or KAT100.
You can test that by tuning into a dummy load at the high power setting 
- or even into a light bulb used as a dummy load (it does not have to be 
50 ohms for this tuner test - likely better if it is not 50 ohms).  If 
the tune completes at the 20 watt level, then declare your Elecraft K2 
gear to be OK and look more carefully at your antenna system.
Are you getting RF Feedback that is troublesome at 20 watts, but not at 
10 watts?
Is there something that is arcing over when 20 watts is applied - it is 
possible that there would be no arcing at 10 watts, but present at 20.  
Is your coax of the foam dielectric type?  If so, be suspicious of it 
since it was exposed to snow melt.  If water gets into coax through even 
a tiny hole in the outer insulation, the coax will be ruined because the 
foam soaks up water just like a sponge.
Check everything, the problem could be anywhere in the system.

73,
Don W3FPR


TWC wrote:
>
> But something is still wrong.
>
> I have tested Relays, Inductors and Capacitors (page 35 in the Manual) 
> and all relays are switching.
>
> When tuning in AUTO mode at 10 watts or less the display on the K2 
> shows the power and 1.0 - 1 for all bands
> and antennas. When tuning at higher power the display only shows 20 
> and I have to stop the tuning manually.
> Sometimes the relays are switching but only SWR led #1 is turned on.
>