Byron,
OK on the DC voltages. You may have to resort to measuring the RF
voltages as indicated in Appendix E of the manual - Transmit Signal
Tracing to find where the failure might be.
Check the value of R98 on the bottom of the RF board. The fact that the
maximum power drops off significantly on the higher bands tells me that
the value of R98 could be greater than the stock value of 270 ohms.
What happens to the voltage at RF Board U9 pin 3 when you do a TUNE? It
should drop to 1/2 the value that it has during receive. If not, Q20 is
not working properly.
For your 160 meter problem - is C153 68pF? Also is C68 10pF (if you
have an older K2, it may be 4.7pF.
On the irregular behavior of the POWER knob, it could be a worn pot -
look at the power displayed as you turn the knob - it should be smooth.
If it is, my suspicion lies with the value of R98. Remember that the
VALC voltage is what actually controls the drive to the TX Mixer, and
the value of R98 is a controlling factor in the power control loop damping.
If this K2 had the KPA100 installed and the power output went up and
down during transmission, the fix is to increase the value of R98 - some
builders went too far with the increase resulting in low power on the
higher bands and possibly 160 meters.
73,
Don W3FPR
On 1/19/2017 10:55 AM, Byron Allen wrote:
Don,
I have now done more tests and bandpass filter alignments....Don,
As you suggested I checked all the voltages in the Elecraft manual on the
RF board. All are good...
Here is the (MAX) power (OUT) int a dummy load on each band and I noticed
something that was peculiar.
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com
