KAT100

[Raimon-3]

Dear Don

This is my last e-mail, sent some days ago.

> My K2/100 is working again
> I replaced D16 and D17, resoldered all components of the wattmeter
> circuits, and all problems with swr and power readings were solved.
> Many, many thanks for your help.
> I was not so happy with the ATU/100.
> When you try to tune, relays switch,  swr leds do not light,  LCD  
> shows  swr 1:1, although it should show more than 2:1, switching stops
> after 2-3 seconds, and if you tune again the process repeats.
> K2/100 and KAT7100 communicate: high or low power indication leds
> light according to the power required, Ant 1 and Ant2 switch
> correctly, all switches switch correctly.

I substituted D1 and D2, but the problem persists.
Connected to a dummy load, and ATU menu to CAL, the LCD of the K2/100
shows the requested power and swr 1:1 (confirmed with an external
wattmeter and swr reader), with the difference that at low power the
first left LED of the ATU100 lights, and at high power none of the LEDS
light.
Switching between CAL and AUTO you hear relays switching, as well as
when switching to L0-L8 etc.
Where should I look to find the reason of this malfunction?
Thanks and best regards
73
EA3EZO
Raimon



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[Don Wilhelm-4]

Raimon,

Re-adjust the null of the KAT100 wattmeter - it is almost, but not quite
right.  After you re-do the null, you will have to go through the power
calibration and SWR calibration again.

The reason that you see the SWR indication on low power and not on high
power is because a scaling factor is used on high power and swamps out
the small reflected voltage at high power, therefore the LED does not
light.  As I said, the null adjustment is close to correct, but not as
close as it should be - you may only have the 'touch the trimmer cap'
slightly to make the difference.
Use a low scale on your DMM when observing the null point and rotate the
capacitor through the area which shows the null to be certain you have
it in the center of the null range.

73,
Don W3FPR

raimon wrote:

> I substituted D1 and D2, but the problem persists.
> Connected to a dummy load, and ATU menu to CAL, the LCD of the K2/100
> shows the requested power and swr 1:1 (confirmed with an external
> wattmeter and swr reader), with the difference that at low power the
> first left LED of the ATU100 lights, and at high power none of the
> LEDS light.
> Switching between CAL and AUTO you hear relays switching, as well as
> when switching to L0-L8 etc.
> Where should I look to find the reason of this malfunction?
> Thanks and best regards
> 73
> EA3EZO
> Raimon
>

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