[Elecraft] K2 - D6

[Don Wilhelm]

Patrick,

If you are driving the K2 with enough signal to be able to read on an RF 
Probe or an oscilloscope, you will have more than enough signal to hear 
quite loudly even though you may have a problem in the receiver.

Can you detect RF voltage with your RF Probe or oscilloscope at the 
antenna jack? If so, then you should have almost that same level signal 
at W1 (OK, it will be reduced a little). If the signal is significantly 
reduced at W1, there is a problem in the T/R switch area. If that is the 
case, check the DC voltages (you can turn the signal generator off for 
this) at the anodes of D2, D3, and D4 - those should all be near 8 
volts. The anode of D5 and D1 should be near zero volts. Check the 
orientation of those diodes against the Parts Placement diagram in the 
back of the manual. Be certain the cathode of D1 and D2 are connected to 
R38 (use your ohmmeter). I recently repaired a K2 that had the left lead 
of R38 inadvertently clipped off when the lead of the RFC on the bottom 
of the board was trimmed - both receive and transmit were sub-par, and 
the transmit problem was quite band dependent.

If you do not have the proper voltages in the T/R switch area, start 
checking first for diode orientation and then for continuity through the 
RF Chokes in the T/R area (consult the schematic to identify those 
chokes. I have repaired several K2s that had one lead of RFC3 broken, 
and if RFC3 is not wound on the correct core, that too will cause 
strange behavior.

BTW - please be more descriptive about your problem and your 
measurements, I am making a lot of assumptions here based on your brief 
post, and each of those assumptions has a good probability of being wrong.

73,
Don W3FPR

Patrick Bourgeois wrote:
> I am not getting any RF on the band side of D6 like the low pass filter troubleshooting guides says I sould nor at Jumper W1... Though I can hear the signal generator quite loudly.
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> Ke5ebs
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> Patrick
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> And Ideas????
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