Well, I apparently mis-diagnosed my issue since after installing all the
components in the K2PAKIT made little difference in the symptoms.
So, back to square one...
Initial conditions: base K2 with KAT2 and KSB2 removed. 7.1 MHz CW, 5 watts set
on power control.
Transmit signal tracing:
John,
For one thing, your TX Buffer output is lower than expected. That may
or may not be a problem.
More important is that there is input to the Bandpass Filter, but no
output. That may be an indication that the frequency of the signal is
not correct.
Do you have the K60XV option or the
Thanks for the info Don.
I just ordered the PA kit from Aptos...
73 de John K2ZA
Sent from my iPad
On Aug 10, 2013, at 0:04, Don Wilhelm w3...@embarqmail.com wrote:
John,
What is the DC voltage at the base of Q7/Q8 during a TUNE? If it is in
excess of 0.64 volts, then Q11 and Q13 as
I was using my new to me K2/10 (S/N 50xx) which has been working flawlessly for
the last 2 months when out of the blue I started getting a P LO message from
the KAT2. I checked the power out with an external meter and it was about .4
watts in general agreement with the K2 power display. No
John,
What is the DC voltage at the base of Q7/Q8 during a TUNE? If it is in
excess of 0.64 volts, then Q11 and Q13 as well as Q7 and Q8 are toast.
Order and install the K2PAKIT which includes all those parts. Q7 and Q8
are connected in push-pull output, so a failure of one will reflect on
Hi Ray.
One possibility might be improper assembly of the transceiver that is causing
the transistors to not mate properly with the heatsink on the bottom chassis.
Been there... done that. :-)
Here's the story behind repeated 2SC1969 failures in my K2 back in 2003, and
the mechanics behind
Ray,
There is one more thing to check. Use an external wattmeter and a dummy
load - check to be certain the actual output power is somewhere near
what the K2 indicates on the display during a TUNE.
If the displayed power is nowhere close to the actual power, then you
need to fix the power
When I read this today it reminded me of a problem that I had with my
TenTec 6M transverter. Sometime after TenTec ceased production of that
kit, they did another run of them. I picked up one from the last
production run, and it performed as advertised. Then out of nowhere the
finals failed
This K2 was a bought from someone on the internet as a working unit etc.
Once received, it blew the finals in about 2 - 3 hours of QSO time. I
really like the K2 but it looks it's mine to solve. I've done a lot of
radoi building and RF troubleshooting down through the years, and have
looked for
Ray,
You apparently have some problem that is destroying your K2 PA
transistors. What I am saying is that the dead PA transistors is the
symptom but not the cause of failure.
When the PA transistors are removed, measure the voltage at the solder
pad for the PA transistor base during a TUNE.
What is the high current alarm set at? Are there the correct number of
turns on T4? (check against the illustration in the assembly manual)
Perhaps there is a problem with the bias system. Transistors Q11 and Q13
should probably be changed as well as the finals if there is a problem
with
Man! You guys are really encouraging-and FAST!
The K2 has ONLY the SSB option at this time. I am building the ATU, 160,
60m, and a few more goodies on my bench as we speak.
---
I bought this on the internet very recently and have basicaly no
information available from the seller. When I
Ray,
Even though you have changed Q11 and Q13, do check the voltage at the
base of Q7 or Q8 both during receive and transmit. It should be zero
during receive and close to 0.6 during transmit.
If that voltage is something different, you will need to look for the
reason before installing (and
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