KAT2 completion problem

[N4TY]

I've been working very slowly on a KAT2, and everything was going well and checking out correctly.
All the relays are working, and I finally arrived at the C55 Bridge Null Adjustment step.

When I put the K2 into TUNE, I got a "Hi Curr" on the panel, and no output power.
Not only that, but an antenna connected to port 1 of the ATU doesn't hear any signals.

A few steps beyond this it asks me to check pin 1 of U4 (LM358) for 0 volts during receive, which is OK.
During TUNE, the voltage isn't 3-4 volts, it's like 0.7 volts.
Oh....and then I realized that I had already installed R6 earlier, instead of after the voltage check.

The shield coax of J7 is closer to the side panel of the K2 when plugged into J6, per the supplied addendum note.
I was very careful taking the bottom cover off, and restoring the PA screws and washers.
This was done to install a new J6, which was installed backwards by the previous owner.

The resistance between ground and the collector of both PA transistors is 87 ohms.
The KAT2 manual says this should be higher than 100 ohms, so I don't know if this is substantial or not.

At this point, I'm stumped.  Comments welcome.
BTW, before I installed the KAT2, the K2 worked perfectly.

73, Tyler N4TY

 
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[Don Wilhelm-4]

Tyler,

Your results are unusual.
Remove the KAT2.  Does the base K2 still work OK?  If not, something has
happened in the meantime.

It would seem that you do not have a good path between the K2 and the
antenna (or perhaps a short to ground).
Check the KAT2 carefully for solder bridges.

With the KAT2 in CAL P mode, you should have zero ohms resistance
between the center conductor of the input coax and he ANT1 jack of the
KAT2. ANT1 (with the KAT2 in CALP or CALs mode).

73,
Don W3FPR

On 7/27/2013 10:34 PM, Tyler Barnett wrote:

> I've been working very slowly on a KAT2, and everything was going well and checking out correctly.
> All the relays are working, and I finally arrived at the C55 Bridge Null Adjustment step.
>
> When I put the K2 into TUNE, I got a "Hi Curr" on the panel, and no output power.
> Not only that, but an antenna connected to port 1 of the ATU doesn't hear any signals.
>
> A few steps beyond this it asks me to check pin 1 of U4 (LM358) for 0 volts during receive, which is OK.
> During TUNE, the voltage isn't 3-4 volts, it's like 0.7 volts.
> Oh....and then I realized that I had already installed R6 earlier, instead of after the voltage check.
>
> The shield coax of J7 is closer to the side panel of the K2 when plugged into J6, per the supplied addendum note.
> I was very careful taking the bottom cover off, and restoring the PA screws and washers.
> This was done to install a new J6, which was installed backwards by the previous owner.
>
> The resistance between ground and the collector of both PA transistors is 87 ohms.
> The KAT2 manual says this should be higher than 100 ohms, so I don't know if this is substantial or not.
>
> At this point, I'm stumped.  Comments welcome.
> BTW, before I installed the KAT2, the K2 worked perfectly.
>
>

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[Tim Heasman]

Hi All,

Many thanks for all your offers, I have now received a f.b. top cover
for my K2.

73

Tim
gm4lmh
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