[Elecraft] Need some help please

[R. Kevin Stover]

Hello all.

I have been working on K2/100 #4684.
It worked beautifully in a QSO with my brother on 40m last weekend until 
the power out went to 0.
Doing some troubleshooting with the procedures in the manual this is 
what I came up with.

I started with the receiver and those measurements were within reason.
I moved on to Transmitter Basic Voltage checks and recorded these voltages.
These are all on the basic K2 with the SSB adapter removed and jumpers 
for J9 and 10 and C167 installed.

D6 Anode on tx - *.25V*
D7 Anode on tx - *7.9V*
Actual Power Output - *0.3W*

I moved on to the ALC voltage checks.

Power Control Test - *4.97V    *Not even close.
------------------------------------------------------------
Transmit Mixer, Buffer, Band-Pass Filter, T-R Switch
*
*Xmit Mixer Output - *.212 Vrms*
Buffer Output - *1.9 Vrms*
Band-Pass Filter Output - *0.056 Vrms
*T-R Switch #1 Output - *0.057 Vrms*

All way too high.
----------------------------------------------------------------------
Pre-Driver, Driver, PA.

Pre-Driver Output - *0.170 Vrms*
Driver Input - *0.024 Vrms*
Driver Output - *4.07 Vrms*
PA Input - Q7 - *.94 Vrms
                 *Q8 -  *1.08 Vrms

*RF Detector Input - *0.0 Vrms *   Not good at all! I checked D9 and it 
is a 1N5711 and it is installed correctly.
------------------------------------------------------------------------------------
PA Transistor Tests. Both flunk with very low resistances.

DMM positive lead on Bases I get about *.65 Ohms* to the collector and 
emitter.
DMM negative lead on Bases I get about *1.7 Ohms *to collector and emitter.

I checked the hardware and thermal pads for both Q7 and Q8 and they're 
all in great shape. No mis-alignments of shoulder washers or thermal 
pads. No torn  thermal pads etc.....

Which component or components are bad.? I suspect I'm going to be buying 
new finals possibly a driver and 1N5711 diode. The voltages are all 
haywire after the pre-driver Q5.

Thanks for your help.

-- 
R. Kevin Stover	ACØH

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