K2 Encoder problems continue.

[Nidge_(G0NIG)]

Turning the dial only results in the last digit displayed flicking backward and forward.  
Initially it was thought that the encoder was at fault and a replacement was ordered.  Unfortunately
once the replacement was installed the problem persisted.  It was suggested by a Don (W3FPR)
that because the voltage on pin 14 of U3 to the encoder enable pin was low
(only 100mV or less) that the output of this drain was faulty.  Replacing the TPIC6B595N
did not rectify the problem.

I have checked continuity between the ENC-A/B outputs of the Encoder through the
display board and back to the MCU and all checks out OK, as does the 5Volt supply.

The remainder of the front panel functions work as they should.

I must admit I am completely stuck now as to what else could cause this problem,
especially as the radio has not missed a beat since it was constructed.

Any pointers that any of you might have would be very much appreciated.

Regards

Nidge (G0NIG)

IO93dv


A wise man speaks because he has something to say; a fool because he has to say something
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Don Wilhelm-4]

Nidge,

Is it that the last digit changes, but the K2 actually changes frequency
(that would be a display problem) - OR - does the K2 frequency not move
properly?

Set the K2 to 40 meters.  Put the internal counter probe into TP1 and
set the menu for CAL FCTR.  Try moving the K2 VFO dial - does the
frequency move with the dial movement (it normally does).
Now put the counter probe in TP3.  Tap the BAND+ button and note the
frequency - it should be near 12,100  kHz.
Now tap the BAND- button and again note the frequency - it should now be
near 12,085 or so, and it should stay there.

If it fails any of those tests, you have a problem with the DC voltage
being applied to the PLL Reference Oscillator.  I can give you some
additional points to check if that appears to be the problem.

73,
Don W3FPR

Nidge (Nigel Smith) wrote:

> Turning the dial only results in the last digit displayed flicking backward and forward.  
> Initially it was thought that the encoder was at fault and a replacement was ordered.  Unfortunately
> once the replacement was installed the problem persisted.  It was suggested by a Don (W3FPR)
> that because the voltage on pin 14 of U3 to the encoder enable pin was low
> (only 100mV or less) that the output of this drain was faulty.  Replacing the TPIC6B595N
> did not rectify the problem.
>
> I have checked continuity between the ENC-A/B outputs of the Encoder through the
> display board and back to the MCU and all checks out OK, as does the 5Volt supply.
>
> The remainder of the front panel functions work as they should.
>
> I must admit I am completely stuck now as to what else could cause this problem,
> especially as the radio has not missed a beat since it was constructed.
>
> Any pointers that any of you might have would be very much appreciated.
>
> Regards
>
> Nidge (G0NIG)
>
> IO93dv
>
>
> A wise man speaks because he has something to say; a fool because he has to say something
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>  

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Nidge_(G0NIG)]

Hi Don and Geoff

Thanks for the replies both.

First of all Geoff: I'm afraid I don't have a scope here anymore.  I did
remove the MCU
and checked the voltages, and this time on pin 14 of U3 I had the correct
voltage close
to 3.8V, with the MCU inserted it was below 100mV.

Don:  I've checked the the readings at TP1, when spinning the encoder the
frequency
does not change.  At TP3 the frequency is close to 12,100KHz with Band +
and close to 12,085KHz with Band - .

I've also checked the 4MHz oscillator and this is spot on.

The radio, when connected to Hamradio Deluxe works fine under computer
control, both
on receive and transmit.  The filters are off but that's because I'm unable
to fine tune them
as the encoder isn't working.

Any more thoughts on the matter greatfully received.

Regards

Nidge (G0NIG)

IO93dv

----- Original Message -----
From: "Don Wilhelm" <[hidden email]>
To: "Nidge (Nigel Smith)" <[hidden email]>
Cc: <[hidden email]>
Sent: Saturday, April 17, 2010 10:27 PM
Subject: Re: [Elecraft] K2 Encoder problems continue.

> Nidge,
>
> Is it that the last digit changes, but the K2 actually changes frequency
> (that would be a display problem) - OR - does the K2 frequency not move
> properly?
>
> Set the K2 to 40 meters.  Put the internal counter probe into TP1 and
> set the menu for CAL FCTR.  Try moving the K2 VFO dial - does the
> frequency move with the dial movement (it normally does).
> Now put the counter probe in TP3.  Tap the BAND+ button and note the
> frequency - it should be near 12,100  kHz.
> Now tap the BAND- button and again note the frequency - it should now be
> near 12,085 or so, and it should stay there.
>
> If it fails any of those tests, you have a problem with the DC voltage
> being applied to the PLL Reference Oscillator.  I can give you some
> additional points to check if that appears to be the problem.
>
> 73,
> Don W3FPR
>
> Nidge (Nigel Smith) wrote:
>> Turning the dial only results in the last digit displayed flicking
>> backward and forward.
>> Initially it was thought that the encoder was at fault and a replacement
>> was ordered.  Unfortunately
>> once the replacement was installed the problem persisted.  It was
>> suggested by a Don (W3FPR)
>> that because the voltage on pin 14 of U3 to the encoder enable pin was
>> low
>> (only 100mV or less) that the output of this drain was faulty.  Replacing
>> the TPIC6B595N
>> did not rectify the problem.
>>
>> I have checked continuity between the ENC-A/B outputs of the Encoder
>> through the
>> display board and back to the MCU and all checks out OK, as does the
>> 5Volt supply.
>>
>> The remainder of the front panel functions work as they should.
>>
>> I must admit I am completely stuck now as to what else could cause this
>> problem,
>> especially as the radio has not missed a beat since it was constructed.
>>
>> Any pointers that any of you might have would be very much appreciated.
>>
>> Regards
>>
>> Nidge (G0NIG)
>>
>> IO93dv
>>
>>
>> A wise man speaks because he has something to say; a fool because he has
>> to say something
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>>

--------------------------------------------------------------------------------



No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 9.0.801 / Virus Database: 271.1.1/2816 - Release Date: 04/17/10
07:31:00

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Don Wilhelm-4]

Nidge,

That means your problem is indeed confined to the display.

It is entirely possible that you have a bad output from the MCU (CB U6)
at pin 14.  The most certain confirmation of that would be to replace it
with another firmware chip.  Yes, with a 'scope, that fact could be
either confirmed or denied, but without that validation, my next best
guess is for a bad output from the MCU at pin 14.

If there is another K2 owner in your area who would allow you to swap
Control Boards from their known working K2, that would confirm that the
MCU chip is the most likely problem source, but lacking that
possibility, the best recourse I can see is to obtain a replacement
firmware chip from Elecraft and try that.  The bottom line is that
digital circuit problems are difficult to analyze without a dual trace
triggered 'scope and some knowledge of the initiating events (to
determine when to trigger the 'scope).

73,
Don W3FPR

Nidge (Nigel Smith) wrote:

> Hi Don and Geoff
>
> Thanks for the replies both.
>
> First of all Geoff: I'm afraid I don't have a scope here anymore.  I did
> remove the MCU
> and checked the voltages, and this time on pin 14 of U3 I had the correct
> voltage close
> to 3.8V, with the MCU inserted it was below 100mV.
>
> Don:  I've checked the the readings at TP1, when spinning the encoder the
> frequency
> does not change.  At TP3 the frequency is close to 12,100KHz with Band +
> and close to 12,085KHz with Band - .
>
> I've also checked the 4MHz oscillator and this is spot on.
>
> The radio, when connected to Hamradio Deluxe works fine under computer
> control, both
> on receive and transmit.  The filters are off but that's because I'm unable
> to fine tune them
> as the encoder isn't working.
>
> Any more thoughts on the matter greatfully received.
>
> Regards
>
> Nidge (G0NIG)
>
>  
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Geoffrey Mackenzie-Kennedy]

Nidge,

Thanks for your reply.

Unfortunately I do not know enough about Hamradio Deluxe nor its interface
with the K2, but rightly or wrongly I assume that if the radio works
properly under computer control, then the MCU (U6) is working as it should
during this mode of control.

I cannot shake my hunch that something is pulling down to near ground either
the ENC A or the ENC B lines (or both) when the MCU is in place. If the
encoder is an optical type, then under such a fault condition I would not be
too surprised if the voltage on ENC RD also dropped to near ground - which
is what you have measured at U3 pin 14. It would be worthwhile to make some
resistance measurements between these three lines and ground, with the power
off - MCU in place and MCU removed.

Not to be overlooked is the possibility that the fault might be mechanical.
For instance if a small sliver of solder had worked its way into the MCU's
socket, it might create a short when the MCU chip is in place - but "open"
when the chip is removed.

Good luck.

73,
Geoff
GM4ESD


On Saturday, April 17, 2010, at 11:13 PM, Nidge (Nigel Smith) wrote:

> Hi Don and Geoff
>
> Thanks for the replies both.
>
> First of all Geoff: I'm afraid I don't have a scope here anymore.  I did
> remove the MCU
> and checked the voltages, and this time on pin 14 of U3 I had the correct
> voltage close
> to 3.8V, with the MCU inserted it was below 100mV.

> The radio, when connected to Hamradio Deluxe works fine under computer
> control, both
> on receive and transmit.  The filters are off but that's because I'm
> unable
> to fine tune them
> as the encoder isn't working.





______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Nidge_(G0NIG)]

Hi Geoff.

It is a real puzzler.  I have checked the voltages on the encoder
and these switch between 4.95V and 100mV when the shaft
is rotated slowly, they don't alternate between each other but
are in sync.  It is possible to change the frequency using the
encoder but only by a small amount and only if the shaft
is spun quickly.

Resistance readings between the 5V supply pin and
the Enc A/B are infinate or beyond the range of my
Fluke 77 meter in one polarity and 3.9MOhm in
the other.

Between Enc A/B it is 8,2MOhm and Infinate
when changing polarity.

Between 5V pin and Enc-enable it is between
4.2MOhm and infinate when changing polarity

Enc A and Enc-enable between 8.15MOhm
and infinate when changing polarity.

Enc B and Enc- enable between 8MOhm and
infinity when changing polarity.

All measurements done with the encoder in
cct.

I have a friend just round the corner from me who
is in the process of building a K2 (has been for
quite a whlie :-) ) so we have arranged to do
some testing this afternoon with his control
and display boards.  He also has a suitable
scope so hopefully I will be able to test the function
of the MCU also.   I also have a Dataman S4 programmer
so the possibility of reflashing the firmware may exist, though
this may be a last resort as I wouldn't want to corrupt his
radio as well.

Again thanks to all on the reflector who have responed.

Will update later today once the comparison tests have been
conducted.

Regards

Nidge (G0NIG)

IO93dv




----- Original Message -----
From: "Geoffrey Mackenzie-Kennedy" <[hidden email]>
To: "Nidge (Nigel Smith)" <[hidden email]>
Cc: "Elecraft Discussion List" <[hidden email]>
Sent: Sunday, April 18, 2010 11:08 AM
Subject: Re: [Elecraft] K2 Encoder problems continue.

> Nidge,
>
> Thanks for your reply.
>
> Unfortunately I do not know enough about Hamradio Deluxe nor its interface
> with the K2, but rightly or wrongly I assume that if the radio works
> properly under computer control, then the MCU (U6) is working as it should
> during this mode of control.
>
> I cannot shake my hunch that something is pulling down to near ground
> either
> the ENC A or the ENC B lines (or both) when the MCU is in place. If the
> encoder is an optical type, then under such a fault condition I would not
> be
> too surprised if the voltage on ENC RD also dropped to near ground - which
> is what you have measured at U3 pin 14. It would be worthwhile to make
> some
> resistance measurements between these three lines and ground, with the
> power
> off - MCU in place and MCU removed.
>
> Not to be overlooked is the possibility that the fault might be
> mechanical.
> For instance if a small sliver of solder had worked its way into the MCU's
> socket, it might create a short when the MCU chip is in place - but "open"
> when the chip is removed.
>
> Good luck.
>
> 73,
> Geoff
> GM4ESD
>
>
> On Saturday, April 17, 2010, at 11:13 PM, Nidge (Nigel Smith) wrote:
>
>> Hi Don and Geoff
>>
>> Thanks for the replies both.
>>
>> First of all Geoff: I'm afraid I don't have a scope here anymore.  I did
>> remove the MCU
>> and checked the voltages, and this time on pin 14 of U3 I had the correct
>> voltage close
>> to 3.8V, with the MCU inserted it was below 100mV.
>
>> The radio, when connected to Hamradio Deluxe works fine under computer
>> control, both
>> on receive and transmit.  The filters are off but that's because I'm
>> unable
>> to fine tune them
>> as the encoder isn't working.
>
>
>
>
>

--------------------------------------------------------------------------------



No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 9.0.801 / Virus Database: 271.1.1/2818 - Release Date: 04/18/10
07:31:00

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html