KPA100 another issue

[n0jrn]

Well,   doesn't seem to my weekend.          :-)

While checking the output of the KPA100  ( during test and alignment )
completed the bias adjustment and began the transmit test.

Connected to my 100 watt dummy load with short jumpers.  Watt meter in line
and checking the output compared to the meter.   Started on 40 meters and at
20    watts all was good.  Moved the power up and noted the amp kicked out
around 35 watts. Started checking other bands at 20 watts and found that on
15 meters,  my current draw went way up and my supplied voltage went way
down.up and my supplied voltage went way down.

Using an Astron VS35M supply.

Wondered if my hook up to the dummy load had an issue so hooked up to a
resonant antenna on 40 and found the amp is still kicking out around 35
watts.

Figured I must have missed a solder joint or something in the low pass
filter for 15 meters and that must be affecting the other bands.   Broke it
all down and check the amp board / low pass filters and all look good.
All the right components in place and the right number of turns on the
roids.  Solder joint appear good and pass continuity tests.
No missed solders.

Now I'm stumped again............

So,  why would one band that shares caps and toroids with two other bands
draw things down so bad.  I've set my power supply at 14 volts and the
display on the K2 is showing 13.8 volts.

I did get high reflected warnings 17 meters when testing with more than 15
watts but I'm puzzled as to how this issue results in the amp kicking out on
all other bands.
( K2's display indicating 1.0-1  when tuning into the dummy load.

Any ideas gang ????

Think I'll pull the caps and see if one of them is opened.

Is there a good method of checking K9 and K10 ????

Again,  thanks for any help:

72        Jerry     N0JRN

( BTW,   my ISP is also acting up and it's taking several hours for my posts
to show up on the reflector )

Back to 40 meters and tried to

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[Don Wilhelm-4]

Jerry,

Have you done the KPA100 wattmeter balance (C1 adjustment) followed by
the forward power calibration (R26)?  If not, the KPA100 may be putting
out a lot more power than indicated by the K2.
If you do not have a good null on the C1 adjustment, you may as well
stop and resolve that problem before attempting to go any further, it is
a critical first step.  Most likely causes for a failure to null are a
problem with T4 or D16, D17 orientation or soldering problems in the
area of T4.

73,
Don W3FPR

n0jrn wrote:

> Well,   doesn't seem to my weekend.          :-)
>
> While checking the output of the KPA100  ( during test and alignment )
> completed the bias adjustment and began the transmit test.
>
> Connected to my 100 watt dummy load with short jumpers.  Watt meter in line
> and checking the output compared to the meter.   Started on 40 meters and at
> 20    watts all was good.  Moved the power up and noted the amp kicked out
> around 35 watts. Started checking other bands at 20 watts and found that on
> 15 meters,  my current draw went way up and my supplied voltage went way
> down.up and my supplied voltage went way down.
>  
>

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