[Elecraft] K2 KPA100 transmit test: fail

[Ron D'Eau Claire]

As a receiver gets heavily overloaded it's not uncommon for the audio output
to drop as amplifier stages are driven so hard they become attenuators. 

As others suggested, the *only* way to confirm is with a wattmeter. 

1) What does the wattmeter built into the K3 say?

2) Did your K3 pass the TX Gain procedure without errors? 

Ron AC7AC 

-----Original Message-----

> Hi All,
> 
> During the course of testing my recently built KPA100, I'm
> experiencing odd results on the cw transmit tests.  All tests,
> resistance, and voltage checks up until this point have been normal.
> 
> When transmitting cw into a 100 watt dummy load, things appear normal
> when transmitting in QRP mode (below 11 watts).  The strength of the
> cw signal on a separate receiver increases in strength as does the
> current draw up until the 11 watt level.
> 
> When the K2 Power level hits 11 watts, the high power relay clicks
> but the signal strength actually drops.  At 20 watts, the signal
> strength on the separate receiver is quieter than at 10 watts.
> However, the current steadily increases and did not drop after the
> high power relay kicked in.
> 
> My approx current draw measurements at key down for various power
> levels (measured by my power supply's meter):
> 
> 5 W    ~ 2 A
> 10 W  ~ 3 A
> 15 W  ~ 7 A
> 25 W  ~ 8 A
> 50 W  ~ 11 A
> 100 W ~16-17 A
> 
> My current draw during tune at less than 11 W is 343 mA (I have a
> number of option modules, fixed audio output mod, and Z10000 output
> buffer).
> 
> My current draw during tune at 11 W plus the fan on low is 545 mA.
> 
> I set the bias current so the current draw during tune at 11 W plus
> fan on low is about 950 mA, although it rises pretty quickly to above
> 1000 mA during tune.
> 
> As always, many thanks for your thoughts and suggestions.
> 
> 73
> 
> N5BCN - Brian