Bill,
That was why Elecraft released MCU 2.04r which is exactly the same as
2.04P, but the sidetone source is locked at U8-4.
That can happen if someone EDITs the ST-L menu and then taps the DISPLAY
button without exiting the menu first.
Many hours of support time had been spent on the "I lost
Bill,
In the KPA100, the normal Vss is about -25 volts, so suspect that
something may be loading that negative supply.
Pull U4 out and measure that voltage again. If it is still not negative
enough, you may have a problem in the T/R switch. Check for 90 to 150
volts on the highest voltage
Alright, I have figured this out.
I’m not sure why I was seeing Vss of -5 volts. I re-checked the negative supply
on the KPA100, flowed the solder on D7 and D8. After that, I was seeing almost
-24 volts at the Vss pin, without U4 in place.
With U4 connected and everything hooked up, Vss was
Don,
Managed to do a little diagnosis.
I pulled the MAX1406 chip KPA100 U4.
I see proper continuity between pin 12 of U4 and pin 25 of the MCU, and pin 11
of U4 and pin 26 of the MCU.
Going back, I checked out the Vdd, Vss an Vcc voltages on U4.
Vdd is 14 volts
Vcc is 5 volts
Vss is -5 volts
Serial Number 2548.
The current MCU I have is version 2.04P. (latest)
The unit I swapped in earlier was, I think 2.03. I don’t have it with me, and
I’m not sure.
> On Nov 18, 2021, at 5:14 PM, Don Wilhelm wrote:
>
> Bill,
>
> What is the level of the MCU (before you changed it), and what
Exactly, working one day with WSJT-X, next day, not.
> On Nov 18, 2021, at 5:10 PM, Don Wilhelm wrote:
>
> Matt,
>
> I Forgot to mention that to Bill. The special cable does not have to be very
> long, but it must be present. Only pins 2, 3 and 5 should connect to the
> RS232 connector on
Yes, I know. I’ve been using the cable that I built back in 2002, when I added
the KPA100, and later modified when I added the KAT100.
> On Nov 18, 2021, at 4:14 PM, Matt Maguire wrote:
>
> Don’t forget, you can’t plug in a USB adapter directly into a K2, as the
> wiring is not standard
Bill,
What is the level of the MCU (before you changed it), and what level did
you try putting in?
And what is the serial number of your K2? Those may help to solve the
problem.
73,
Don W3FPR
On 11/18/2021 3:55 PM, Bill Coleman wrote:
U6 is kinda expensive to just replace….
I do have an
Matt,
I Forgot to mention that to Bill. The special cable does not have to be
very long, but it must be present. Only pins 2, 3 and 5 should connect
to the RS232 connector on the USB to serial adapter. Failure to follow
this will cause several "strange happenings" with the K2. The subject
Don’t forget, you can’t plug in a USB adapter directly into a K2, as the
wiring is not standard RS232C. You need to make up a special adapter as
described in the manual. Probably you know this already, but just something
else to check.
73, Matt VK2RQ
On Fri, 5 Nov 2021 at 06:31, Bill Coleman
U6 is kinda expensive to just replace….
I do have an older revision of the firmware for U6. I did try before
substituting the KPA100 U4, and it didn’t address the issue.
I guess this will require more sleuthing.
> On Nov 16, 2021, at 12:35 PM, Don Wilhelm wrote:
>
> Bill,
>
> Plug the
Bill,
Plug the ribbon cable in and do an end to end continuity test - KPA100
U4 pin 12 to Control Board U6 pin 25,
And KPA100 U4 pin 11 to CB U6 pin 26. That will check the board wiring
and the ribbon cable.
If all that is OK, try replacing CB U6.
73,
Don W3FPR
On 11/15/2021 7:28 PM, Bill
Well, I cut out the existing U4 MAX1406 chip on the KPA100 and soldered in a
16-pin socket. Putting in a new MAX1406 chip in the newly installed socket and
… same problem as before. The radio does not respond to commands, pressing the
PORT TEST does not result in any data output.
I haven’t had
Yes, Vss Vdd and Vcc all look like appropriate values.
> On Nov 4, 2021, at 3:47 PM, Don Wilhelm wrote:
>
> Bill,
>
> Make certain you have +12 volts on U4 pin 1 and +5 volts on U4 pin 16 and
> about -25 volts (-8 to -27 volts) on U4 pin 8.
> If those are correct, replace U4 and it should
Bill,
Make certain you have +12 volts on U4 pin 1 and +5 volts on U4 pin 16
and about -25 volts (-8 to -27 volts) on U4 pin 8.
If those are correct, replace U4 and it should work)
73,
Don W3FPR
On 11/4/2021 3:29 PM, Bill Coleman wrote:
About 10 days ago, I was having trouble with the
About 10 days ago, I was having trouble with the K2/100, as it was no longer
talking to WSJT-X correctly. I could get the audio running, but it would never
contact the radio.
Trying to set up for CQ WW Phone, I had the same trouble with N1MM.
Tried to use the PORT TEST feature by going to the
So I’m just gonna say this:
He’s Don the Mon (that’s Spanish for ‘man’)!
Thanks,
Mike NJ2OM
> On Jul 26, 2020, at 10:54 AM, Don Wilhelm wrote:
>
> Mike,
>
> That is good news - it sounds like you are back in business with the K2/100.
>
> 73,
> Don W3FPR
>
>> On 7/25/2020 12:19 PM, Mike
Final update...
After several weeks of troubleshooting, led by Don, W3FPR, of realigning
bandpass filters, checking RF and DC voltages per the K2 manual, and finally
confirming that the bias voltages were correct to the Q7 & Q8 finals, Don
suggested ordering the K2PAKIT and replacing the
Mike,
You are the only one who can determine this. Everyone else is reduced to
guessing because they don't have access to your PSU/K2/power lead.
Simple:
Measure the PSU voltage on RX at the PUS terminals.
Measure the PSU voltage on TX set to 100W at the PSU terminals.
Compare both of these
Don, this is what you sent earlier:
“If the power supply voltage is not the problem, then remove the KPA100 from
the base K2 and realign the bandpass filters. Connect a dummy load to the base
K2 BNC ANT jack. After that, check the maximum power from the base K2 - you
should have at least 10
Yep I’m familiar with that formula.
One of the tests in the assembly instructions was to test the current draw at
100w. It was 13A. The acceptable range was 13-18A so I thought that was a good
result.
Thanks,
Mike NJ2OM
> On Jun 30, 2020, at 11:20 PM, Nr4c wrote:
>
> Watts is Volts X
Watts is Volts X Amps.
Fewer Volts means more Amps. More Amps means more work for power supply,
leading to fewer Volts. Fewer Volts means ...( you get the picture).
Sent from my iPhone
...nr4c. bill
> On Jun 30, 2020, at 8:37 PM, Mike Kopacki wrote:
>
> I didn’t have ring connectors big
.@embarqmail.com
Cc: "elecraft@mailman qth. net"
Sent: Wednesday, July 1, 2020 12:34:48 AM
Subject: Re: [Elecraft] K2 K2/100 post FD review
I didn’t have ring connectors big enough but I did have spade connectors. I
crimped and soldered them but there was no change in the voltage reading
ilto:donw...@embarqmail.com>
*Sent: *Tuesday, June 30, 2020 6:01 PM
*To: *Mike Kopacki <mailto:mikekopa...@gmail.com>
*Cc: *elecraft@mailman qth. net <mailto:elecraft@mailman.qth.net>
*Subject: *Re: [Elecraft] K2 K2/100 post FD review
Mike,
You should have only 0.3 volts drop IN the K2 itself
Mike,
The K2 RF gain is higher on 80, 40, and 30 meters. It takes a bit more
drive and current on the higher bands.
Have you verified the power output of the base K2 with the KPA100
removed? That is an important parameter to investigate.
After verifying that the base K2 is capable of
me.
>>>
>>> The P/S output is 13.6V. I’m seeing 13.1V at the K2. If the normal drop
>>> is .3V, it should read 13.3V at the K2. Is the difference of .2V
>>> “substantial”?
>>>
>>> Mike NJ2OM
>>>
>>> Sent from Mail <ht
10
>>
>> *From: *Don Wilhelm <mailto:donw...@embarqmail.com>
>> *Sent: *Tuesday, June 30, 2020 6:01 PM
>> *To: *Mike Kopacki <mailto:mikekopa...@gmail.com>
>> *Cc: *elecraft@mailman qth. net <mailto:elecraft@mailman.qth.net>
>> *Subject: *Re: [Elec
gt;
*Cc: *elecraft@mailman qth. net <mailto:elecraft@mailman.qth.net>
*Subject: *Re: [Elecraft] K2 K2/100 post FD review
Mike,
You should have only 0.3 volts drop IN the K2 itself, so given your
display of 13.1 volts on the K2, that says you have a substantial
voltage drop in the power cabl
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Mike,
You should have only 0.3 volts drop IN the K2 itself, so given your
display of 13.1 volts on the K2, that says you have a substantial
voltage drop in the power cable.
Is it wired directly to the power supply? Are all the connections
tight? Is the APP assembly at the K2 correct? Look
The connections may be tight, but how many are there? Are you running straight
from the power supply to the radio without any intervening junction points, Rig
Runners, etc.?
Grant NQ5T
> On Jun 30, 2020, at 5:32 PM, Mike Kopacki wrote:
>
> Don...
>
> The power supply is an MFJ 13.8V/25A
Don...
The power supply is an MFJ 13.8V/25A switching power supply. It measures 13.63V
at the terminals.
The K2 shows 13.1V in receive mode.
During transmit on all bands, the K2 shows 11.3-11.9V, depending on the band.
All the power connections appear to be tight.
Thanks,
Mike NJ2OM
>
Mike,
It is not reasonable to expect a normal wattmeter to have greater than a
10% accuracy.
Consider that the spec for a Bird wattmeter is only 5% right after
calibration.
Digital wattmeters can be much more accurate, such as the LP-100 from
Telepostinc, but they are calibrated to NIST
Okay. I will go back to your first reply and run through the items you
suggested.
Does the fact that on 40 and 80 meters, when I set the requested power to 100w,
I actually see a little more - like 103w - but the power drops off on other
bands - is that a clue to anything?
Thanks,
Mike NJ2OM
Mike,
No, the KPA100 wattmeter will display the actual power being produced if
it is well calibrated.
That is not necessarily the same as the requested power, although with a
properly working KPA100 and a calibrated KPA100 wattmeter, the reading
should be the same.
73,
Don W3FPR
On
I can run through some of the items you suggest. But I don’t have an external
wattmeter that can measure 100 watts. I do have a QRP wattmeter.
I will start tomorrow to try and work through the question.
But to be completely accurate...you are saying that the KPA100 wattmeter (which
is what I
Congratulations, Mike! Please let us ALL know how it goes, as we of the K2
clan learn something with every post.
73 Eric WD6DBM
On Sun, Jun 28, 2020, 2:12 PM Mike Kopacki wrote:
> Well, that gives me something to do! I’ll let you know how it goes.
>
> Thanks,
> Mike NJ2OM
>
> > On Jun 28,
Well, that gives me something to do! I’ll let you know how it goes.
Thanks,
Mike NJ2OM
> On Jun 28, 2020, at 4:41 PM, Don Wilhelm wrote:
>
> Mike,
>
> Congratulations on finishing the K2/100.
>
> On the power output variation, that is not normal.
> First check the voltage delivered to
Mike,
Congratulations on finishing the K2/100.
On the power output variation, that is not normal.
First check the voltage delivered to the K2 while in transmit.
You should do that by tapping DISPLAY and scrolling to the voltage
display. Your power source should provide at least 13.8 volts,
I was able to finish my KPA100 a few days ago, just in time for Field Day.
The amp worked flawlessly! No error messages, over heating, etc. made 451
contacts on CW and phone with no bad reports.
I am extremely pleased and wish to thank the Elecraft team for developing
such a great kit!
I did
Bill,
Yes, as long as the KPA100 is physically connected to the base K2, its
wattmeter will be used for power control. The base K2 provides power to
the critical circuits and MCU in the KPA100 even though the PA is turned
off in the menu or not powered via the APP connector.
You MUST
So, if you turn the KPA100 off via the menu, the KPA100 SWR bridge is still
used in any case?
I’ll plan to add 50-100 kOhm resistors across the output, as you suggested. I’m
also going to re-do the calibration of both SWR meters, just make sure no
damage was done to the KAT100.
> On May 25,
I only partially answered the question about when each wattmeter is used.
If the KAT100 is connected to a QRP K2 (KPA100 physically removed)
through a KIO2, then the KAT100 wattmeter will be used for power control
and SWR display in the K2 display.
As long as the KPA100 is physically
Bill,
Both wattmeters (KPA100 and KAT100) are in-line at the same time. With
the KPA100 installed the KAT100 wattmeter is only used to calculate the
SWR and use that value to light the SWR bargraph. But otherwise they are
electrically equal.
Why the KPA100 diodes get zapped while the KAT100
Don, I have one question.
This is the second time my K2/100 has completely toasted D16 and D17. I also
have a KAT100 connected at the same time, which has virtually identical SWR
bridge.
How is it that a static discharge can destroy D16 and D17, but the diodes D1
and D2 in the KAT100 are
OK, I removed D16 and D17, and on the diode setting of my DVM, they both
measured the same value both forward and backward - 034. Which means they were
totally shorted.
I replaced them with new diodes (which measured 316 forward, and infinite
backward), and the RF display is once again
Took me over week to check this, but power is the same whether Tune or
Tune/Display — 100 watts!
So, the suspects are likely D16 & D17.
Fortunately, the last time I replaced them I put in a couple of pins from a
machined pin socket, so it should be an easy job.
I’ve had to replace U6 before
Bill,
Set the power at 50 watts and do a TUNE.
Is the output power at 20 to 25 watts? If so, so far so good.
Now try a TUNE/DISPLAY (hold both buttons at once). Is the power near
50 watts? If so, you have proper power control and the problem is with
the LED display.
OTOH, if the actual
I’ve recently seem a problem with my K2/100. It transmits ok, and the power
level out tracks the power control, but the power indication LEDs remain at
zero.
No, I’m not in ALC mode, I’m definitely in RF mode for the meter.
I’m using an external wattmeter (a Kenwood AT-250 in passthrough
Gene,
I also thought Tom N0SS originated that mod, but I did not find it on
his website (preserved by the Mid-Missouri Amateur Radio Club).
73,
Don W3FPR
On 1/10/2019 11:06 AM, Gene O wrote:
I have a RS232 cable which I made for another project. I plan to change
one of the DB9 connectors to
I have a RS232 cable which I made for another project. I plan to change
one of the DB9 connectors to a male version. In essence it will end up
being the cable that is shown in Figure 41 of the K2/100 manual, page 55.
My computer has a RS232 port and the female end of this cable will go
Gene,
You must NOT plug a standard serial cable into that 9 pin AUX connector.
It is not RS-232 although there are 3 RS-232 signal lines in the
connector. The remaining signals are internal K2 signals that are used
with external Elecraft equipment like the KAT100, the KRC2 and the XV
I have a K2 with the 100W, K2/100, mounted in the top. I want to obtain
a RS232 cable with male DB9 on one end and female on the other.
In order to make the connection in the back or the K2 it seems the male
plug needs to be modified. That is a slot cut so that it fits the
key/tab that is
Curt,
A lot of information can be gleaned from reading the K2 specifications
which say the VFO stability is less than 100 Hz drift typical from a
cold start at 25 degC.
That means yours is well within specification.
That also means you should let it warm up for 15 minutes or so from a
cold
I built K2 s/n 06424 some time ago, then added KSB2 and finally converted it to
100W a few years ago. Usually used it for CW only, but recently moved it to
main operating position and started using it on 40M LSB mornings. To my
chagrin, received comment few days ago that I was off frequency,
for your help, Don.
Bill, VE2WMA
-Original Message-
From: Don Wilhelm [mailto:w3...@embarqmail.com]
Sent: Thursday, January 30, 2014 4:50 PM
To: William Moore; d...@w3fpr.com; elecraft@mailman.qth.net; 'Mike Harris'
Subject: Re: [Elecraft] [K2] K2-100 Test and Alignment Issues
Bill
PM
To: William Moore; d...@w3fpr.com; elecraft@mailman.qth.net; 'Mike Harris'
Subject: Re: [Elecraft] [K2] K2-100 Test and Alignment Issues
Bill,
Regarding T4, there is one other possibility that I did not mention before.
If the direction of the windings is not as shown in the manual, it will work
To: William Moore; elecraft@mailman.qth.net
Subject: Re: [Elecraft] [K2} K2-100 Test and Alignment Issues
Bill,
For the J3+ lead, I think the PA transistors may be producing that voltage
in response to light shining on them. Shield the transistors from light and
see if the voltage changes - if so
Bill,
Regarding T4, there is one other possibility that I did not mention
before. If the direction of the windings is not as shown in the manual,
it will work backwards which may be what you are observing.
As for the minimum voltage of 1.4 volts, that is WAY too high. The
bridge should
As John has pointed out, the problem can be anywhere in the KPA100
wattmeter circuit consisting of T4, C1, C95. R28, R29, D16, D17, R26,
R27, U5. R24. R25, Q10, Q11, and U6. With a bit more information and
some measurements that I can suggest, the field of suspect components
(and soldering
Bill - I had this exact problem on my K2/100 during testing. Changing
C1 varied the power output, but the SWR was fixed at 9.9-1. The problem
was a short between the output of the two op-amps U5A and U5B that
amplify and buffer the forward and reflected voltages before they go to
the
I am now into the test and alignment phases of my just constructed KPA-100
amplifier to be integrated into K2 #3842. Right from the start of this
phase, I have run headlong into a two issues I just can't figure out.
I am constructing from the Revision G September 2010 manual. On the page 47,
the
By the way - adjust C1 with a non-metallic screwdriver. Both sides of
C1 are above ground.
73,
Don W3FPR
Bill,
For the J3+ lead, I think the PA transistors may be producing that
voltage in response to light shining on them. Shield the
Bill,
For the J3+ lead, I think the PA transistors may be producing that
voltage in response to light shining on them. Shield the transistors
from light and see if the voltage changes - if so, ignore it.
As for the C1 adjustment - do the following steps in order. Preset R26
and R27 to
I have lost power control on K2/100. RF output goes to full power no
matter what the setting.
I checked D16/D17 on the KPA100 and they seem to be OK. I'll search the
mailing list for some other things to check, but any ideas would be
appreciated.
david de AJ4TF
--
View this message in
David,
That symptom is caused by the output power not being communicated back
to the base K2 microprocessor.
The normal reason is diodes D16 and D17, but there are other reasons as
well. U6 is another probable failure point.
To take some stress off things in the KPA100, power the base K2
Thanks Don,
I did restore R98 to its original 270 ohms (from 1k0) and power output on
10m SSB is back to a full 100W+
The ALC dithering is noticeable, but I'm not going to fiddle any more.
Might see if i can just live with it and if not, I'll experiment some more
to find a lower value of R98
Just noticed that power out on 10m (28490) CW and in TUNE mode is 85W, but
maximum PEP on SSB is 30W.
All other bands, I get 100W out in CW/TUNE SSB. I'm checking this by
running K2/100 into a 50 ohm dummy load. Wattmeters are a WavenodeWN-2 and
Autek WM1. Same PO PEP recorded with both.
John,
As a quick check, reduce the value of R98 back to 270 ohms (put a 360 or
390 ohm resistor in parallel with your 1k0 resistor).
That will quickly tell you if the cause is due to the increased value of
R98.
If that is the problem, you may have to compromise further on the
damping of the
Hi All,
I've just finished K2/100 #6998. After blowing the PA transistors of the
base K2 by accidentally dropping the frequency probe into the works, I've
completed the KPA100, installed it and all is working very well. Made
several SSB contacts tonight and I couldn't be happier. I have a
John,
I have not discovered the source of that birdie, but it is there.
Yes, 20 Hz is the DAC limit in the K2.
73,
Don W3FPR
On 11/2/2010 7:50 AM, VK7JB wrote:
Hi All,
I've just finished K2/100 #6998. After blowing the PA transistors of the
base K2 by accidentally dropping the frequency
Hi John,
Glad to hear that after all of your bad luck your K2/100 is now working
well.
The strong birdie at 3589 kHz was also present in my K2/100 before I
embarked on a birdie killing project a few years ago, which involved a fair
amout of difficult surgery. This particular birdie is the
I have the 100W amp mounted in an EC2 enclosure, all working great now, no
small thanks to Don!
I have a question. The little fan on the back seems to push air into the
unit, yet there is no obvious exit for it. Or am I missing something?
Almost seems like I need an automatic vent popping up at
Where does all the hot air go?
Why into the mic, of course
LOL!
Actually, when the KPA is mounted in the rig, there is space along the
front of the heat sink, right where it meets the stubby little front
panel. Probably the same in the EC2.
Yes, the fan (whizzer!) is loud and annoying. I
Stephen,
The air exits just behind the front plate - through the fins of the heat
sink. There is lots of exit area, no need to worry.
As far as just how fast the fan comes on, that depends on the
temperature (of the heat sink at the PA transistor locations). CAL TPA
must be set in the
On 16/10/07 20:55, Darwin, Keith [EMAIL PROTECTED] wrote:
Where does all the hot air go?
Why into the mic, of course
LOL!
I should have expected that! In my defence of course, I can add that
although I have the mic plugged in, it hasn't been used yet!
Now that I have been prompted
Thanks, Johnny, Eric, Don, Brian and others who responded.
Part of the K2's success must be attributable to how well the company and
community have adapted to changes since the K2 was first produced. No doubt the
foreseeable future will bring even more changes.
Speaking for myself, the K2 and
Hi There,
What I am wondering, is (are) the K2 and K2/100 a 'dead radio(s)'?
Over, say 8 - x years.
73
Wyn, VR2AX
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On May 26, 2007, at 8:24 AM, Wyn wrote:
Hi There,
What I am wondering, is (are) the K2 and K2/100 a 'dead radio(s)'?
IMHO they are not. I have an ICOM IC-706mkII (not a 'g'). It is 10
years old. Compared to the K2 and Ke3 it is a dog. But it looks and
works like new so I have no
Wyn,
I expect the K2 to be not only available new for some (unknown) time
into the future, but for it to be fully supported by Elecraft long after
that.
Yes, the K3 will outperform the K2, but those of us who have K2s already
we can attest to the fact that the K2 is not a slouch performer.
Absolutely not! We are still actively manufacturing and selling the K2
and K2/100.
73, Eric WA6HHQ
Wyn wrote:
What I am wondering, is (are) the K2 and K2/100 a 'dead radio(s)'?
Over, say 8 - x years.
73
Wyn, VR2AX
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