Aaron,
It is likely that the PA transistors have failed.
Pull the top cover off and measure the voltage at the BASE of either Q7
or Q8. During receive, it should be zero, and during transmit it should
be in the range of 0.60 to 0.64 volts.
If it is anything other than that, remove the PA trans
I got a question about the Elecraft K2. A friend borrowed mine and he said
that he was running PSK31 and it just shut down on him and after that it
would no longer transmit. Once I got it back it seems to be working but not
transmitting. Am I correct in assuming that it is the PA transistors that
n
Lars,
First, turn the power all the way down and attach a dummy load to
protect your K2.
It will have to be a process of elimination to determine where the
problem source may be.
You are looking for a short on the dot line. Keep the K2 in CW mode.
First, remove the KSB2 board (no jumpers re
Sounds like C1 may be short circuit, jack J1 may have failed, or there could be
a short somewhere between jack J1, the trace that runs along the RF board from
J1 to J8 pin 18, or where the corresponding track on the control board runs to
the MCU pin 30. There's not much to go wrong, so I'd sugge
I’m hoping for some advice on where to start troubleshooting a problem that
started this afternoon.
Before I start digging into the K2 perhaps someone on the list has had a
similar problem and can help save some time in troubleshooting and repair.
Here is what I’m experiencing.
While listening
Hi All,
I have a question.
Does the band select output from the K2 (Aux bus signal coming out of
the back of the KPA100) the same signal information that is output by
the K3? I am looking at interfacing an amp to the K2 and there is an
off-the-shelf cable available but it is advertised as a K3 to
On 5/31/2010 6:59 AM, Alexey Kats wrote:
>>> Anyway... I know that older version of K2 manual refers to changing
>>> winding of T4 transformer to 2:2 (instead of original 2:3) in order to
>>> increase efficiency of CW performance on 5W or less.
Keep in mind that the 25% decrease in current draw a
No worries, I'll do that (I hate it myself when I have to work on
customized equipment when the owner either forgot about it, or didn't
even know about it since it's not the original owner). Fortunately,
the last time it happened with me was many years ago. And the most
embarrassing part was that w
Alexey,
The R2 that is referred to by DK3RED is on the Front Panel - it is the
power control pot.
There will be no change to any of the alignment procedures with the
change in the T4 winding ratio.
Please put a sticker inside your K2 stating that the T4 winding ratio is
intentionally changed
Thank you, Don, for responding so early (I hope you do not have
insomnia as I do). And yes, that's exactly what I am looking for - K2
restricted to 5W and to CW-only operation, so as long as it is safe
and is not going to introduce spurious emission it'll work for me.
On Mon, May 31, 2010 at 6:31
Alexey,
Make that change IF AND ONLY IF 1) you will never install the KSB2, AND
2) you will not operate above the 5 watt level.
That change makes the K2 PA transistors more efficient at 5 watts and
below, but the operation is non-linear and the efficiency is worse if
the power is increased abo
Sorry, I managed to press the wrong key and sent it before I finished it.
Anyway... I know that older version of K2 manual refers to changing
winding of T4 transformer to 2:2 (instead of original 2:3) in order to
increase efficiency of CW performance on 5W or less. Is it still
applicable to the cu
I have one more question about K2. I noticed that revision C of K2
manual says that if to increase QRP T4 transfor
--
Alexey Kats (neko)
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Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailm
Just in case anyone else is suffering from unstable power out in tune mode,
I followed Don’s advice (as below) and changed R98 on the RF (270ohm) board
for a 1.5K resistor (I actually had a measured value of 1.64K on the POT but
1.5k was the closest fixed resistor I had).
Now when I enter tune, po
Thanks Don, I'll begin looking...
Jeff
On 4/23/07, Don Wilhelm <[EMAIL PROTECTED]> wrote:
Jeff,
I was really asking if the power jumped to 160 watts regardless of the
setting of the power control so I could better suggest where the problem
might be - apparently it does not go to 160 watts if y
Jeff,
I was really asking if the power jumped to 160 watts regardless of the
setting of the power control so I could better suggest where the problem
might be - apparently it does not go to 160 watts if you set the power
lower.
That behavior is not normal, and right now I would strongly susp
Don, thanks.
I do have a recently-made KPA100 (~3 months) and have installed the
upgraded C31 to combat the parasitic.
When in QSO, I see the power jump up, and it seems to stay there until
I enter a TUNE operation or manually drop the power level via the
power knob.
I spend a lot of time on 40
Jeff,
If you are saying that you see an occasional jump from 120 watts power
to 140 or even 160, I would say that *MAY* be possible, but if it jumps
from 50 (or even 80) watts to 160, then you do have a problem - and my
first reaction is that it is an indication of a transient oscillation.
H
Thanks Don and others for the answers.
In my case, I'm trying to run down a proble where the KPA100 will be
fine, then all of a sudden it's output will jump up over 140W. I
thought that the high output in the base K2 might be the cause. So are
we saying that some variation is ok, and once in a wh
ble and smooth in power output.
Brett
N2DTS
> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Jeff
> Kinzli N6GQ
> Sent: Sunday, April 22, 2007 11:51 PM
> To: [EMAIL PROTECTED]
> Cc: Elecraft Mail Posting
> Subject: Re
ppose I'll just
have to live with this little quirk. I still wouldn't trade K2 for another
radio!!
David, VK2NU
Date: Sun, 22 Apr 2007 20:50:38 -0700
From: "Jeff Kinzli N6GQ" <[EMAIL PROTECTED]>
Subject: Re: [Elecraft] Question about K2 power meter
To: [EMAIL PROTE
Jeff,
That is normal behavior - the power will climb a bit if left in TUNE for
a period of time. It is mostly the result of heating in the PA
transistors. In normal operation, either with CW or SSB, there is not a
constant carrier being transmitted and the same conditions will not be
presen
U
Date: Sun, 22 Apr 2007 20:50:38 -0700
From: "Jeff Kinzli N6GQ" <[EMAIL PROTECTED]>
Subject: Re: [Elecraft] Question about K2 power meter
To: [EMAIL PROTECTED]
Cc: Elecraft Mail Posting
Message-ID:
<[EMAIL PROTECTED]>
Content-Type: text/plain; charset=ISO-8859-1; fo
Hi Don,
Thanks for the replies.
To answer your questions, the problem occurs into a dummy load.
I set the base K2 (without KPA100 connected) to 5.0W, and then TUNE,
and it starts at 5.0W and heads upwards to 5.7-6.0W (read from the
display, as well as the S-meter). After about 10 seconds in TUN
Jeff,
Another thought and a question - does the K2 control power properly
(check with TUNE) when the requested power is set to 5 watts? If you
get somewhere between 4.5 and 5.5 watts output with the requested power
set to 5, then the power control circuits are working as they should be.
Set
Jeff,
Is this into an antenna or into a dummy load? If it is into an antenna,
'strange things can happen' in the basic K2 configuration when the
antenna is not 50 ohms pure resistive.
Work into a dummy load first to resolve the situation (or answer your
questions). The LED bargraph should
Don and others,
A few weeks back, a user posted about an issue with low power output
with his K2. Don said:
If you do not have either the KAT2, the KPA100, or the KAT100 installed, the
K2 does not display the actual power output on the LCD (the requested power
is displayed briefly when the powe
Hi Guys,
I've got a question regarding SSB audio troubleshooting. I mainly use the K2
as my "CW rig". But I was recently checking it out on SSB. On 20m USB, I was
getting a report that my audio sounded distorted. I adjusted the transmit
filter OP1 to adjust the BFO setting, which seemed to
3dB gain reference to what?
Without a reference decibel values are meaningless. With voltage, 3db gain
is a value greater by one half and is only applicable if the impedances remain
the same across the item of equipment you are measuring. When referred to
power, 3dB gain is greater by x 2 (
Tom Mc wrote:
I have built K2 s/n 1103 and used manual version B. My manual (ver. B)
states that the winding ratio should be 11:3. Don states that newer manuals
are stating that T7 should be 20:5.
Don's post also states that an additional 3 dB of gain should be
accomplished by this change.
Hi,
A recent post by Don, W3FPR mentioned that the winding of T7 in the K2 has
changed, apparently with K2 manual revision C.
I have built K2 s/n 1103 and used manual version B. My manual (ver. B)
states that the winding ratio should be 11:3. Don states that newer manuals
are stating that T
tt
Sent: Monday, October 04, 2004 10:39
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Question about K2's Q7 and Q8 Final Amp
On Monday 04 October 2004 08:16, [EMAIL PROTECTED] wrote:
> Hi,
>
> My K2 has been working fine but I decided to fix it anyway...hi.
>
The K2 man
On Monday 04 October 2004 08:16, [EMAIL PROTECTED] wrote:
> Hi,
>
> My K2 has been working fine but I decided to fix it anyway...hi.
>
The K2 manual warns that whenever the heat sink is
> removed and replaced you should verify that the collectors of Q7 and Q8 are
> not shorted to ground.
>
> T
Tom,
Quite rare, but if you have a short with the heatsink off, look for a
soldering problem with T4 or T4 might have an internal short (unlikely, but
possible). You might try lifting the 1 and 2 terminals of T4 to further
isolate the collectors and confirm that T4 is the culprit.
Ask yours
Hi,
My K2 has been working fine but I decided to fix it anyway...hi.
Well actually I was a little short on the power output on 10 meters. I was
getting about 7 watts out on 10 meters and Gary Suggested that I replace T2 and
T1. Instead of winding them myself, I contacted 'The Toroid Guy'
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