[Elecraft] K3 .4 wattsr

Ed Gray W0SD w0sd at triotel.net
Wed Jun 18 23:47:47 EDT 2008


Tech support is closed for the night so I am looking for ideas?

The K3 worked after I put it together at 10 watts.  When I put in the 
100 watt PA I got an error message.  Thinking the 100 watts PA was bad I 
took it out and tried to go back to 10 watts but now it won't work at 
low power.

I have been trying to trace the RF with the K2 RF Probe and find I don't 
have RF very early on.

The following is at 1.850 with the power set at 5 watts and in tune.

With a K2 RF probe at the tip of the coax coming from J7 on KREF3 that 
goes into J65 on the RF board I am getting .01 to .02 reading with my 
DMM in the 20 volt scale.  This is the actual reading on the display. 
It is my understanding I should be getting around .111    The cable is good.

The following is the same as above but the reading is taken in receive 
and is the same reading in transmit.

I am getting .16 to .17 at the tip of the coax coming from J2 on KREF3 
that goes into J83 on the KSYN3.  It is my understanding this should be 
around .784   Again the cable is good.

The leads on the TXCO certainly appear to be long enough.  The K3 works 
on receive but I did have a lot of difficulty in zero beating with WWV 
so this might indicate I have a low level of output from the TXCO.  The 
dot on the TXCO is as shown on the picture.

I get a ERR TXG and that is the only error message I get other than when 
I have J83 unplugged.

I have the FL1 position populated with the stock 2.7 khz filter and TX 
enabled for all modes for FL1 the stock 2.7 khz filter.  That is the 
widest filter I have.

I am absolutely positive nothing is touching on the bottom of the KREF3 
board to the shield.

I have looked at the KREF3 with a magnifying glass and everything looks 
good.  I have wiggled everything I can and see no variation in the 
measured levels.

Do I have a bad KREF3 board or is there something "stupid" I am 
overlooking.  The K3 puts out about .4 watts in tune when set for 5 watts.

I am not sure if I should have tech MD on or off but I get the same 
reading either way.

VCO MD works fine, no error messages.

Ideas?

Ed W0SD







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