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Re: K2 trouble shooting

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WE0H

Re: K2 trouble shooting

Hi Don,

Ref K2 #6698:

I tried a new encoder but it did nothing different than the original
encoder. Tonight I see that ENC-A is only 2v p-p while ENC-B is 5v p-p.
This is measured right on the encoder terminals and on the U6 MCU chip.
I don't see any resistor network pull ups on these lines. Do you think
the MCU could have gotten hurt with the spike on the 14v VCC line that
shorted the one final and that VCC filter cap? I see data on both ENC
lines when I spin the encoder. The Encoder VCC is a solid 5.0vdc. All
other functions work on this radio except anything where I need to turn
the encoder to access something in a menu or change anything. The radio
receives fine on whatever the display freq is and transmits fine on the
same freq on all bands. I just can't change any VFO digit other than the
far right digit, or if I spin the encoder shaft left & right, it will
slowly increase the displayed freq but not go down.

Mike
WE0H
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Don Wilhelm-4

Re: K2 trouble shooting

Mike,

Other than the wiring paths for ENC A and ENC B signals through the
connectors and to CB U6 pins 8 and 16,
there is nothing else for these two signals. However, for the encoder
to be read, the /ENC RD signal must be at a low level and that signal is
generated from FP U3 pin 14. Look for low going pulses with your
scope. If they are not present, FP U3 may be at fault.

73,
Don W3FPR

Mike-WE0H wrote:

> Hi Don,
>
> Ref K2 #6698:
>
> I tried a new encoder but it did nothing different than the original
> encoder. Tonight I see that ENC-A is only 2v p-p while ENC-B is 5v p-p.
> This is measured right on the encoder terminals and on the U6 MCU chip.
> I don't see any resistor network pull ups on these lines. Do you think
> the MCU could have gotten hurt with the spike on the 14v VCC line that
> shorted the one final and that VCC filter cap? I see data on both ENC
> lines when I spin the encoder. The Encoder VCC is a solid 5.0vdc. All
> other functions work on this radio except anything where I need to turn
> the encoder to access something in a menu or change anything. The radio
> receives fine on whatever the display freq is and transmits fine on the
> same freq on all bands. I just can't change any VFO digit other than the
> far right digit, or if I spin the encoder shaft left & right, it will
> slowly increase the displayed freq but not go down.
>
> Mike
> WE0H
>
>

______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
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WE0H

Re: K2 trouble shooting

Hi Don,

OK, on that line which is pin 14 on U3, there is only a couple mv but no
pulses. The state of that line never changes. The other strange thing is
the ENC-A data level only being 2v p-p verses ENC-B which is a full 5v
p-p signal. Shouldn't both ENC data lines be a full 5v p-p TTL signal?

Worst case, does Elecraft take in repairs direct? I could send in both
display boards if that is the case. I sure wish I had test boards to
swap in, to verify which board is causing the issues.

I received the final amp rebuilding components the other day but I will
wait to install them until after this dead VFO issue is repaired.

Mike
WE0H

Don Wilhelm wrote:

> Mike,
>
> Other than the wiring paths for ENC A and ENC B signals through the
> connectors and to CB U6 pins 8 and 16,
> there is nothing else for these two signals. However, for the encoder
> to be read, the /ENC RD signal must be at a low level and that signal
> is generated from FP U3 pin 14. Look for low going pulses with your
> scope. If they are not present, FP U3 may be at fault.
>
> 73,
> Don W3FPR
>
>
> Mike-WE0H wrote:
>> Hi Don,
>>
>> Ref K2 #6698:
>>
>> I tried a new encoder but it did nothing different than the original
>> encoder. Tonight I see that ENC-A is only 2v p-p while ENC-B is 5v
>> p-p. This is measured right on the encoder terminals and on the U6
>> MCU chip. I don't see any resistor network pull ups on these lines.
>> Do you think the MCU could have gotten hurt with the spike on the 14v
>> VCC line that shorted the one final and that VCC filter cap? I see
>> data on both ENC lines when I spin the encoder. The Encoder VCC is a
>> solid 5.0vdc. All other functions work on this radio except anything
>> where I need to turn the encoder to access something in a menu or
>> change anything. The radio receives fine on whatever the display freq
>> is and transmits fine on the same freq on all bands. I just can't
>> change any VFO digit other than the far right digit, or if I spin the
>> encoder shaft left & right, it will slowly increase the displayed
>> freq but not go down.
>>
>> Mike
>> WE0H

Don Wilhelm-4

Re: K2 trouble shooting

Mike,

Do you have the 'scope vertical amp set to DC? This is logic level
switching and the DC levels are significant, not the peak to peak
variation. Yes, the levels must be above or below the switching thresholds.
On the /ENC RD line, compare it to the levels at FP U3 pins 6 and/or 16
- it should be similar.
To really tell the whole story, one would have to use 3 probes on the
'scope - trigger on the /ENC RD signal going low and observe the state
of the ENC A and ENC B signals at that time.

Elecraft does repairs, but only on complete kits. If this is the route
you need to go, contact [hidden email] for further information and
obtain an RSA number with instructions for packing and where to send it.

73,
Don W3FPR

Mike-WE0H wrote:

> Hi Don,
>
> OK, on that line which is pin 14 on U3, there is only a couple mv but no
> pulses. The state of that line never changes. The other strange thing is
> the ENC-A data level only being 2v p-p verses ENC-B which is a full 5v
> p-p signal. Shouldn't both ENC data lines be a full 5v p-p TTL signal?
>
> Worst case, does Elecraft take in repairs direct? I could send in both
> display boards if that is the case. I sure wish I had test boards to
> swap in, to verify which board is causing the issues.
>
> I received the final amp rebuilding components the other day but I will
> wait to install them until after this dead VFO issue is repaired.
>
> Mike
> WE0H
>
>
>
> Don Wilhelm wrote:
>
>> Mike,
>>
>> Other than the wiring paths for ENC A and ENC B signals through the
>> connectors and to CB U6 pins 8 and 16,
>> there is nothing else for these two signals. However, for the encoder
>> to be read, the /ENC RD signal must be at a low level and that signal
>> is generated from FP U3 pin 14. Look for low going pulses with your
>> scope. If they are not present, FP U3 may be at fault.
>>
>> 73,
>> Don W3FPR
>>
>>
>> Mike-WE0H wrote:
>>
>>> Hi Don,
>>>
>>> Ref K2 #6698:
>>>
>>> I tried a new encoder but it did nothing different than the original
>>> encoder. Tonight I see that ENC-A is only 2v p-p while ENC-B is 5v
>>> p-p. This is measured right on the encoder terminals and on the U6
>>> MCU chip. I don't see any resistor network pull ups on these lines.
>>> Do you think the MCU could have gotten hurt with the spike on the 14v
>>> VCC line that shorted the one final and that VCC filter cap? I see
>>> data on both ENC lines when I spin the encoder. The Encoder VCC is a
>>> solid 5.0vdc. All other functions work on this radio except anything
>>> where I need to turn the encoder to access something in a menu or
>>> change anything. The radio receives fine on whatever the display freq
>>> is and transmits fine on the same freq on all bands. I just can't
>>> change any VFO digit other than the far right digit, or if I spin the
>>> encoder shaft left & right, it will slowly increase the displayed
>>> freq but not go down.
>>>
>>> Mike
>>> WE0H
>>>
>
> ______________________________________________________________
> 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: 8.5.424 / Virus Database: 270.14.47/2478 - Release Date: 11/03/09 07:36:00
>
>

WE0H

Re: K2 trouble shooting

Hi Don,

OK, I can see those signals on pin 6 & 16 easily. Pin 14 is dead. It
stays low. I am using DC coupling. ENC-A is only going to 2v and ENC-B
goes to 5v. Both those data lines show data when the encoder is spun in
either direction. Both lines will either rest at zero or a high state.
But, ENC-A high is 2v not 5v. ENC-B high is 5v. Something is not right
with ENC-A. If I pull the jumper wire from the encoder's ENC-A line and
put the scope on the encoder's ENC-A terminal, I now get the 5v p-p
signal that I would expect out of the encoder. So with that said, the
MCU is not letting the ENC-A data line swing from 0-5v. It only allows a
0-2v swing which is not enough. Would you agree the MCU is faulty & the
U3 IC? Having two IC's giving troubles is rare but this radio suffered
from severe spikes on the 14v line which shorted a electrolytic cap and
one final transistor.

BTW, I am copying this to the Elecraft reflector so it is in the
database for someone else down the road. This is definitely a strange
problem with this radio. I think we are getting closer to the solution.

Mike
WE0H

Don Wilhelm wrote:

> Mike,
>
> Do you have the 'scope vertical amp set to DC? This is logic level
> switching and the DC levels are significant, not the peak to peak
> variation. Yes, the levels must be above or below the switching
> thresholds.
> On the /ENC RD line, compare it to the levels at FP U3 pins 6 and/or
> 16 - it should be similar.
> To really tell the whole story, one would have to use 3 probes on the
> 'scope - trigger on the /ENC RD signal going low and observe the state
> of the ENC A and ENC B signals at that time.
>
> Elecraft does repairs, but only on complete kits. If this is the
> route you need to go, contact [hidden email] for further
> information and obtain an RSA number with instructions for packing and
> where to send it.
>
> 73,
> Don W3FPR
>
> Mike-WE0H wrote:
>> Hi Don,
>>
>> OK, on that line which is pin 14 on U3, there is only a couple mv but
>> no pulses. The state of that line never changes. The other strange
>> thing is the ENC-A data level only being 2v p-p verses ENC-B which is
>> a full 5v p-p signal. Shouldn't both ENC data lines be a full 5v p-p
>> TTL signal?
>>
>> Worst case, does Elecraft take in repairs direct? I could send in
>> both display boards if that is the case. I sure wish I had test
>> boards to swap in, to verify which board is causing the issues.
>>
>> I received the final amp rebuilding components the other day but I
>> will wait to install them until after this dead VFO issue is repaired.
>>
>> Mike
>> WE0H
>>
>>
>>
>> Don Wilhelm wrote:
>>
>>> Mike,
>>>
>>> Other than the wiring paths for ENC A and ENC B signals through the
>>> connectors and to CB U6 pins 8 and 16,
>>> there is nothing else for these two signals. However, for the
>>> encoder to be read, the /ENC RD signal must be at a low level and
>>> that signal is generated from FP U3 pin 14. Look for low going
>>> pulses with your scope. If they are not present, FP U3 may be at
>>> fault.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>>
>>> Mike-WE0H wrote:
>>>
>>>> Hi Don,
>>>>
>>>> Ref K2 #6698:
>>>>
>>>> I tried a new encoder but it did nothing different than the
>>>> original encoder. Tonight I see that ENC-A is only 2v p-p while
>>>> ENC-B is 5v p-p. This is measured right on the encoder terminals
>>>> and on the U6 MCU chip. I don't see any resistor network pull ups
>>>> on these lines. Do you think the MCU could have gotten hurt with
>>>> the spike on the 14v VCC line that shorted the one final and that
>>>> VCC filter cap? I see data on both ENC lines when I spin the
>>>> encoder. The Encoder VCC is a solid 5.0vdc. All other functions
>>>> work on this radio except anything where I need to turn the encoder
>>>> to access something in a menu or change anything. The radio
>>>> receives fine on whatever the display freq is and transmits fine on
>>>> the same freq on all bands. I just can't change any VFO digit other
>>>> than the far right digit, or if I spin the encoder shaft left &
>>>> right, it will slowly increase the displayed freq but not go down.
>>>>
>>>> Mike
>>>> WE0H

Don Wilhelm-4

Re: K2 trouble shooting

Mike,

Yes, it sounds like you have it adequately analyzed and I do agree with
your conclusions. FP U3 has a bad pin 14 output and the MCU input for
ENC A also has a problem and is dragging the signal down.

73,
Don W3FPR

Mike-WE0H wrote:

> Hi Don,
>
> OK, I can see those signals on pin 6 & 16 easily. Pin 14 is dead. It
> stays low. I am using DC coupling. ENC-A is only going to 2v and ENC-B
> goes to 5v. Both those data lines show data when the encoder is spun in
> either direction. Both lines will either rest at zero or a high state.
> But, ENC-A high is 2v not 5v. ENC-B high is 5v. Something is not right
> with ENC-A. If I pull the jumper wire from the encoder's ENC-A line and
> put the scope on the encoder's ENC-A terminal, I now get the 5v p-p
> signal that I would expect out of the encoder. So with that said, the
> MCU is not letting the ENC-A data line swing from 0-5v. It only allows a
> 0-2v swing which is not enough. Would you agree the MCU is faulty & the
> U3 IC? Having two IC's giving troubles is rare but this radio suffered
> from severe spikes on the 14v line which shorted a electrolytic cap and
> one final transistor.
>
> BTW, I am copying this to the Elecraft reflector so it is in the
> database for someone else down the road. This is definitely a strange
> problem with this radio. I think we are getting closer to the solution.
>
> Mike
> WE0H
>
>
>
> Don Wilhelm wrote:
>
>> Mike,
>>
>> Do you have the 'scope vertical amp set to DC? This is logic level
>> switching and the DC levels are significant, not the peak to peak
>> variation. Yes, the levels must be above or below the switching
>> thresholds.
>> On the /ENC RD line, compare it to the levels at FP U3 pins 6 and/or
>> 16 - it should be similar.
>> To really tell the whole story, one would have to use 3 probes on the
>> 'scope - trigger on the /ENC RD signal going low and observe the state
>> of the ENC A and ENC B signals at that time.
>>
>> Elecraft does repairs, but only on complete kits. If this is the
>> route you need to go, contact [hidden email] for further
>> information and obtain an RSA number with instructions for packing and
>> where to send it.
>>
>> 73,
>> Don W3FPR
>>
>> Mike-WE0H wrote:
>>
>>> Hi Don,
>>>
>>> OK, on that line which is pin 14 on U3, there is only a couple mv but
>>> no pulses. The state of that line never changes. The other strange
>>> thing is the ENC-A data level only being 2v p-p verses ENC-B which is
>>> a full 5v p-p signal. Shouldn't both ENC data lines be a full 5v p-p
>>> TTL signal?
>>>
>>> Worst case, does Elecraft take in repairs direct? I could send in
>>> both display boards if that is the case. I sure wish I had test
>>> boards to swap in, to verify which board is causing the issues.
>>>
>>> I received the final amp rebuilding components the other day but I
>>> will wait to install them until after this dead VFO issue is repaired.
>>>
>>> Mike
>>> WE0H
>>>
>>>
>>>
>>> Don Wilhelm wrote:
>>>
>>>
>>>> Mike,
>>>>
>>>> Other than the wiring paths for ENC A and ENC B signals through the
>>>> connectors and to CB U6 pins 8 and 16,
>>>> there is nothing else for these two signals. However, for the
>>>> encoder to be read, the /ENC RD signal must be at a low level and
>>>> that signal is generated from FP U3 pin 14. Look for low going
>>>> pulses with your scope. If they are not present, FP U3 may be at
>>>> fault.
>>>>
>>>> 73,
>>>> Don W3FPR
>>>>
>>>>
>>>> Mike-WE0H wrote:
>>>>
>>>>
>>>>> Hi Don,
>>>>>
>>>>> Ref K2 #6698:
>>>>>
>>>>> I tried a new encoder but it did nothing different than the
>>>>> original encoder. Tonight I see that ENC-A is only 2v p-p while
>>>>> ENC-B is 5v p-p. This is measured right on the encoder terminals
>>>>> and on the U6 MCU chip. I don't see any resistor network pull ups
>>>>> on these lines. Do you think the MCU could have gotten hurt with
>>>>> the spike on the 14v VCC line that shorted the one final and that
>>>>> VCC filter cap? I see data on both ENC lines when I spin the
>>>>> encoder. The Encoder VCC is a solid 5.0vdc. All other functions
>>>>> work on this radio except anything where I need to turn the encoder
>>>>> to access something in a menu or change anything. The radio
>>>>> receives fine on whatever the display freq is and transmits fine on
>>>>> the same freq on all bands. I just can't change any VFO digit other
>>>>> than the far right digit, or if I spin the encoder shaft left &
>>>>> right, it will slowly increase the displayed freq but not go down.
>>>>>
>>>>> Mike
>>>>> WE0H
>>>>>
>
> ______________________________________________________________
> 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: 8.5.424 / Virus Database: 270.14.49/2480 - Release Date: 11/04/09 07:37:00
>
>

WE0H

Re: K2 trouble shooting

OK, I will contact the Elecraft Parts department and see how to order
these two components. Thank you again and lets hope this is the final
answer to this damaged K2. I will post when and what all was required to
repair this radio on this reflector so it may help others if they run
into this sort of issue.

Mike
WE0H

Don Wilhelm wrote:
> Mike,
>
> Yes, it sounds like you have it adequately analyzed and I do agree
> with your conclusions. FP U3 has a bad pin 14 output and the MCU
> input for ENC A also has a problem and is dragging the signal down.
>
> 73,
> Don W3FPR

>
> Mike-WE0H wrote:
>> Hi Don,
>>
>> OK, I can see those signals on pin 6 & 16 easily. Pin 14 is dead. It
>> stays low. I am using DC coupling. ENC-A is only going to 2v and
>> ENC-B goes to 5v. Both those data lines show data when the encoder is
>> spun in either direction. Both lines will either rest at zero or a
>> high state. But, ENC-A high is 2v not 5v. ENC-B high is 5v. Something
>> is not right with ENC-A. If I pull the jumper wire from the encoder's
>> ENC-A line and put the scope on the encoder's ENC-A terminal, I now
>> get the 5v p-p signal that I would expect out of the encoder. So with
>> that said, the MCU is not letting the ENC-A data line swing from
>> 0-5v. It only allows a 0-2v swing which is not enough. Would you
>> agree the MCU is faulty & the U3 IC? Having two IC's giving troubles
>> is rare but this radio suffered from severe spikes on the 14v line
>> which shorted a electrolytic cap and one final transistor.
>>
>> BTW, I am copying this to the Elecraft reflector so it is in the
>> database for someone else down the road. This is definitely a strange
>> problem with this radio. I think we are getting closer to the solution.
>>
>> Mike
>> WE0H
>>
>>
>>
>> Don Wilhelm wrote:
>>
>>> Mike,
>>>
>>> Do you have the 'scope vertical amp set to DC? This is logic level
>>> switching and the DC levels are significant, not the peak to peak
>>> variation. Yes, the levels must be above or below the switching
>>> thresholds.
>>> On the /ENC RD line, compare it to the levels at FP U3 pins 6 and/or
>>> 16 - it should be similar.
>>> To really tell the whole story, one would have to use 3 probes on
>>> the 'scope - trigger on the /ENC RD signal going low and observe the
>>> state of the ENC A and ENC B signals at that time.
>>>
>>> Elecraft does repairs, but only on complete kits. If this is the
>>> route you need to go, contact [hidden email] for further
>>> information and obtain an RSA number with instructions for packing
>>> and where to send it.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> Mike-WE0H wrote:
>>>
>>>> Hi Don,
>>>>
>>>> OK, on that line which is pin 14 on U3, there is only a couple mv
>>>> but no pulses. The state of that line never changes. The other
>>>> strange thing is the ENC-A data level only being 2v p-p verses
>>>> ENC-B which is a full 5v p-p signal. Shouldn't both ENC data lines
>>>> be a full 5v p-p TTL signal?
>>>>
>>>> Worst case, does Elecraft take in repairs direct? I could send in
>>>> both display boards if that is the case. I sure wish I had test
>>>> boards to swap in, to verify which board is causing the issues.
>>>>
>>>> I received the final amp rebuilding components the other day but I
>>>> will wait to install them until after this dead VFO issue is repaired.
>>>>
>>>> Mike
>>>> WE0H
>>>>
>>>>
>>>>
>>>> Don Wilhelm wrote:
>>>>
>>>>
>>>>> Mike,
>>>>>
>>>>> Other than the wiring paths for ENC A and ENC B signals through
>>>>> the connectors and to CB U6 pins 8 and 16,
>>>>> there is nothing else for these two signals. However, for the
>>>>> encoder to be read, the /ENC RD signal must be at a low level and
>>>>> that signal is generated from FP U3 pin 14. Look for low going
>>>>> pulses with your scope. If they are not present, FP U3 may be at
>>>>> fault.
>>>>>
>>>>> 73,
>>>>> Don W3FPR
>>>>>
>>>>>
>>>>> Mike-WE0H wrote:
>>>>>
>>>>>> Hi Don,
>>>>>>
>>>>>> Ref K2 #6698:
>>>>>>
>>>>>> I tried a new encoder but it did nothing different than the
>>>>>> original encoder. Tonight I see that ENC-A is only 2v p-p while
>>>>>> ENC-B is 5v p-p. This is measured right on the encoder terminals
>>>>>> and on the U6 MCU chip. I don't see any resistor network pull ups
>>>>>> on these lines. Do you think the MCU could have gotten hurt with
>>>>>> the spike on the 14v VCC line that shorted the one final and that
>>>>>> VCC filter cap? I see data on both ENC lines when I spin the
>>>>>> encoder. The Encoder VCC is a solid 5.0vdc. All other functions
>>>>>> work on this radio except anything where I need to turn the
>>>>>> encoder to access something in a menu or change anything. The
>>>>>> radio receives fine on whatever the display freq is and transmits
>>>>>> fine on the same freq on all bands. I just can't change any VFO
>>>>>> digit other than the far right digit, or if I spin the encoder
>>>>>> shaft left & right, it will slowly increase the displayed freq
>>>>>> but not go down.
>>>>>>
>>>>>> Mike
>>>>>> WE0H