- Display dead after 30m/80m install

[dave.wilburn]

I'm helping a friend troubleshoot a KX1.  Unit was fine after build.
Took unit apart and installed 30m/80m.  Then 3rd digit did not work on
display.  He re-flowed some pins on the unit (I do not know which ones
and he does not recall) and now the display is not functional at all.

I started him checking through the resistance checks on page 26 of the
  document.  Pins 1 & 20 of U1 has about 500 ohm on it, whether U1 is
installed or not.

We have been all through the voltages with D3/D2, U8, and U9.  All the
  regulators seem good.  Though I did caution him about running from a
wall wart.  His 12v seems a bit low.  Around 11.5v.

As a result of this, the voltage on pin 4 of U1 is a bit low at 3.5v.
  Also pin 14 is at 2.5v where it is supposed to be low.

I find little odds and ends here that are not right, but if the
display is not functional I would expect bigger issues.  Some voltage
off on clock inputs wouldn't seem the culprit.  Also the ATU was not
plugged in.

We have worked through the troubleshooting tree, problem 00,  I need
to review with him where he is on problem 20.  We looked through
problem 26.  No pins are bent on U1.  All of the voltages were good
except the 2 mentioned.

I have not built a KX1, but built a K2.  My thoughts are to go through
the various resistance and voltage checks for the 3 build sections and
see if we can make any sense of it.

Am I headed in the right direction?  Am I missing anything obvious
since I am not familiar with the KX1?

I'm hoping my friend (John, K6OWD) got setup on the list today.

Dave Wilburn
NM4M
K2/100 S/N 5982
K3/100 S/N 766
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[Don Wilhelm-4]

Dave,

It sounds like U1 is not plugged in securely.  When U1 is inserted into
the socket, most of the narrow part of the IC pins are fully into the
socket.  It does take a bit of pressure to seat U1 in the machine pin
socket.  Make certain all the pins are started into the socket pins and
then apply pressure with both thumbs on the IC body, fingers under the
board and squeeze until the leads seat completely.

If that does not cure the problems, look critically at the soldering.  
The solder should flow out to an almost invisible edge on both the
solder pad and the component lead at each connection.  If there is a
defined edge to the solder, insufficient heat was applied during the
soldering process.  I am not certain why, but from the number of KX1
repairs that I have done, soldering problems are more common with the
KX1 than other Elecraft kits.  Perhaps builders are more hesitant to
apply sufficient heat due to the more dense component placement, but
somehow that does happen.  If the solder connections look more like '
balls' than 'mountains' having a concave fillet, you can be certain
insufficient heat was used during the soldering process, and the only
cure is to wick away the excess solder and apply good solder using
sufficient heat (700 to 750 deg F).

73,
Don W3FPR

David Wilburn wrote:

> I'm helping a friend troubleshoot a KX1.  Unit was fine after build.
> Took unit apart and installed 30m/80m.  Then 3rd digit did not work on
> display.  He re-flowed some pins on the unit (I do not know which ones
> and he does not recall) and now the display is not functional at all.
>
> I started him checking through the resistance checks on page 26 of the
>   document.  Pins 1 & 20 of U1 has about 500 ohm on it, whether U1 is
> installed or not.
>
> We have been all through the voltages with D3/D2, U8, and U9.  All the
>   regulators seem good.  Though I did caution him about running from a
> wall wart.  His 12v seems a bit low.  Around 11.5v.
>
> As a result of this, the voltage on pin 4 of U1 is a bit low at 3.5v.
>   Also pin 14 is at 2.5v where it is supposed to be low.
>
> I find little odds and ends here that are not right, but if the
> display is not functional I would expect bigger issues.  Some voltage
> off on clock inputs wouldn't seem the culprit.  Also the ATU was not
> plugged in.
>
> We have worked through the troubleshooting tree, problem 00,  I need
> to review with him where he is on problem 20.  We looked through
> problem 26.  No pins are bent on U1.  All of the voltages were good
> except the 2 mentioned.
>
> I have not built a KX1, but built a K2.  My thoughts are to go through
> the various resistance and voltage checks for the 3 build sections and
> see if we can make any sense of it.
>
> Am I headed in the right direction?  Am I missing anything obvious
> since I am not familiar with the KX1?
>
> I'm hoping my friend (John, K6OWD) got setup on the list today.
>
> Dave Wilburn
> NM4M
> K2/100 S/N 5982
> K3/100 S/N 766
> _______________________________________________
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>
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> ------------------------------------------------------------------------
>
>
> No virus found in this incoming message.
> Checked by AVG - http://www.avg.com 
> Version: 8.0.176 / Virus Database: 270.10.14/1918 - Release Date: 1/27/2009 7:26 AM
>
>  

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[dave.wilburn]

Ok Don.  Will do.  I have been helping him remotely.  I will get over
there and take a look at it.  Just as a follow-up, he got his test
readings to me.  Here they are;

Resistance Table

U1 Called for >1k
Pin 1 - .582
Pin 20 - .582
Pins 3, 4, 8, and 19 all had correct readings.


D2 & D3 s1 on >1k

D2 & D3 s1 off >10k

Voltage Checks U1
1 - ok
2 - 0v (S/B 5v)
3 - 2.5v (S/B 4.6v)
4 - 2.5v (S/B 4.9v)
5 - 4.14 (S/B 4.9v - this is likely close enough)
6 - 4.90 (S/B 3.4v)
7 -> 12 good readings
13 - 00v (S/B 5.0v)
14 - 2.46v (S/B 00v)
15 -> 20 good readings
21 -> .1v (S/B 5.0v)
22 -> .1v (S/B 5.0v)
23 -> 28 good readings

U2
8 -> 2.91v (S/B 1.32v)
14 -> 1.27v (S/B 00v)

I asked John to describe where the shoulders of the U1 chip were, in
relation to the seats in the holder.  He said the wide part of the
pin, was seated all the way down in the socket.  I am going to try to
get by his place to give the thing a visual, but it sounds like he has
good solder and U1 well seated.

Dave Wilburn
NM4M

Don Wilhelm wrote:

> Dave,
>
> It sounds like U1 is not plugged in securely.  When U1 is inserted into
> the socket, most of the narrow part of the IC pins are fully into the
> socket.  It does take a bit of pressure to seat U1 in the machine pin
> socket.  Make certain all the pins are started into the socket pins and
> then apply pressure with both thumbs on the IC body, fingers under the
> board and squeeze until the leads seat completely.
>
> If that does not cure the problems, look critically at the soldering.  
> The solder should flow out to an almost invisible edge on both the
> solder pad and the component lead at each connection.  If there is a
> defined edge to the solder, insufficient heat was applied during the
> soldering process.  I am not certain why, but from the number of KX1
> repairs that I have done, soldering problems are more common with the
> KX1 than other Elecraft kits.  Perhaps builders are more hesitant to
> apply sufficient heat due to the more dense component placement, but
> somehow that does happen.  If the solder connections look more like '
> balls' than 'mountains' having a concave fillet, you can be certain
> insufficient heat was used during the soldering process, and the only
> cure is to wick away the excess solder and apply good solder using
> sufficient heat (700 to 750 deg F).
>
> 73,
> Don W3FPR
>
> David Wilburn wrote:
>> I'm helping a friend troubleshoot a KX1.  Unit was fine after build.
>> Took unit apart and installed 30m/80m.  Then 3rd digit did not work on
>> display.  He re-flowed some pins on the unit (I do not know which ones
>> and he does not recall) and now the display is not functional at all.
>>
>> I started him checking through the resistance checks on page 26 of the
>>   document.  Pins 1 & 20 of U1 has about 500 ohm on it, whether U1 is
>> installed or not.
>>
>> We have been all through the voltages with D3/D2, U8, and U9.  All the
>>   regulators seem good.  Though I did caution him about running from a
>> wall wart.  His 12v seems a bit low.  Around 11.5v.
>>
>> As a result of this, the voltage on pin 4 of U1 is a bit low at 3.5v.
>>   Also pin 14 is at 2.5v where it is supposed to be low.
>>
>> I find little odds and ends here that are not right, but if the
>> display is not functional I would expect bigger issues.  Some voltage
>> off on clock inputs wouldn't seem the culprit.  Also the ATU was not
>> plugged in.
>>
>> We have worked through the troubleshooting tree, problem 00,  I need
>> to review with him where he is on problem 20.  We looked through
>> problem 26.  No pins are bent on U1.  All of the voltages were good
>> except the 2 mentioned.
>>
>> I have not built a KX1, but built a K2.  My thoughts are to go through
>> the various resistance and voltage checks for the 3 build sections and
>> see if we can make any sense of it.
>>
>> Am I headed in the right direction?  Am I missing anything obvious
>> since I am not familiar with the KX1?
>>
>> I'm hoping my friend (John, K6OWD) got setup on the list today.
>>
>> Dave Wilburn
>> NM4M
>> K2/100 S/N 5982
>> K3/100 S/N 766
>> _______________________________________________
>> Elecraft mailing list
>> Post to: [hidden email]
>> You must be a subscriber to post to the list.
>> Subscriber Info (Addr. Change, sub, unsub etc.):
>>  http://mailman.qth.net/mailman/listinfo/elecraft   
>> Help: http://mailman.qth.net/subscribers.htm
>> Elecraft web page: http://www.elecraft.com
>> ------------------------------------------------------------------------
>>
>>
>> No virus found in this incoming message.
>> Checked by AVG - http://www.avg.com Version: 8.0.176 / Virus Database:
>> 270.10.14/1918 - Release Date: 1/27/2009 7:26 AM
>>
>>  
>

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[Don Wilhelm-4]

Dave,

Without the display operating, the voltages on U1 pins 3, 4, 5, and 21
through 28 will not be as expected, and who knows what the
microprocessor is trying to do under those conditions.
It is beginning to sound like a case of 'too much solder' creating
solder bridges and covering up inadequately heated connections.  You
might suggest that he review the soldering tutorial on the Elecraft
Builder's Resource page and compare his solder connections to the
figures in that document.  If there is too much solder, the only way I
know to cure the problems is to remove it with solder wick or a
de-soldering iron.  That task takes 2 hours or more on a KX1 if it is
required.

73,
Don W3FPR

David Wilburn wrote:

> Ok Don.  Will do.  I have been helping him remotely.  I will get over
> there and take a look at it.  Just as a follow-up, he got his test
> readings to me.  Here they are;
>
> Resistance Table
>
> U1 Called for >1k
> Pin 1 - .582
> Pin 20 - .582
> Pins 3, 4, 8, and 19 all had correct readings.
>
>
> D2 & D3 s1 on >1k
>
> D2 & D3 s1 off >10k
>
> Voltage Checks U1
> 1 - ok
> 2 - 0v (S/B 5v)
> 3 - 2.5v (S/B 4.6v)
> 4 - 2.5v (S/B 4.9v)
> 5 - 4.14 (S/B 4.9v - this is likely close enough)
> 6 - 4.90 (S/B 3.4v)
> 7 -> 12 good readings
> 13 - 00v (S/B 5.0v)
> 14 - 2.46v (S/B 00v)
> 15 -> 20 good readings
> 21 -> .1v (S/B 5.0v)
> 22 -> .1v (S/B 5.0v)
> 23 -> 28 good readings
>
> U2
> 8 -> 2.91v (S/B 1.32v)
> 14 -> 1.27v (S/B 00v)
>
> I asked John to describe where the shoulders of the U1 chip were, in
> relation to the seats in the holder.  He said the wide part of the
> pin, was seated all the way down in the socket.  I am going to try to
> get by his place to give the thing a visual, but it sounds like he has
> good solder and U1 well seated.
>
> Dave Wilburn
> NM4M
>
> Don Wilhelm wrote:
>  
>> Dave,
>>
>> It sounds like U1 is not plugged in securely.  When U1 is inserted into
>> the socket, most of the narrow part of the IC pins are fully into the
>> socket.  It does take a bit of pressure to seat U1 in the machine pin
>> socket.  Make certain all the pins are started into the socket pins and
>> then apply pressure with both thumbs on the IC body, fingers under the
>> board and squeeze until the leads seat completely.
>>
>> If that does not cure the problems, look critically at the soldering.  
>> The solder should flow out to an almost invisible edge on both the
>> solder pad and the component lead at each connection.  If there is a
>> defined edge to the solder, insufficient heat was applied during the
>> soldering process.  I am not certain why, but from the number of KX1
>> repairs that I have done, soldering problems are more common with the
>> KX1 than other Elecraft kits.  Perhaps builders are more hesitant to
>> apply sufficient heat due to the more dense component placement, but
>> somehow that does happen.  If the solder connections look more like '
>> balls' than 'mountains' having a concave fillet, you can be certain
>> insufficient heat was used during the soldering process, and the only
>> cure is to wick away the excess solder and apply good solder using
>> sufficient heat (700 to 750 deg F).
>>
>> 73,
>> Don W3FPR
>>
>> David Wilburn wrote:
>>    
>>> I'm helping a friend troubleshoot a KX1.  Unit was fine after build.
>>> Took unit apart and installed 30m/80m.  Then 3rd digit did not work on
>>> display.  He re-flowed some pins on the unit (I do not know which ones
>>> and he does not recall) and now the display is not functional at all.
>>>
>>> I started him checking through the resistance checks on page 26 of the
>>>   document.  Pins 1 & 20 of U1 has about 500 ohm on it, whether U1 is
>>> installed or not.
>>>
>>> We have been all through the voltages with D3/D2, U8, and U9.  All the
>>>   regulators seem good.  Though I did caution him about running from a
>>> wall wart.  His 12v seems a bit low.  Around 11.5v.
>>>
>>> As a result of this, the voltage on pin 4 of U1 is a bit low at 3.5v.
>>>   Also pin 14 is at 2.5v where it is supposed to be low.
>>>
>>> I find little odds and ends here that are not right, but if the
>>> display is not functional I would expect bigger issues.  Some voltage
>>> off on clock inputs wouldn't seem the culprit.  Also the ATU was not
>>> plugged in.
>>>
>>> We have worked through the troubleshooting tree, problem 00,  I need
>>> to review with him where he is on problem 20.  We looked through
>>> problem 26.  No pins are bent on U1.  All of the voltages were good
>>> except the 2 mentioned.
>>>
>>> I have not built a KX1, but built a K2.  My thoughts are to go through
>>> the various resistance and voltage checks for the 3 build sections and
>>> see if we can make any sense of it.
>>>
>>> Am I headed in the right direction?  Am I missing anything obvious
>>> since I am not familiar with the KX1?
>>>
>>> I'm hoping my friend (John, K6OWD) got setup on the list today.
>>>
>>> Dave Wilburn
>>> NM4M
>>> K2/100 S/N 5982
>>> K3/100 S/N 766
>>> _______________________________________________
>>> Elecraft mailing list
>>> Post to: [hidden email]
>>> You must be a subscriber to post to the list.
>>> Subscriber Info (Addr. Change, sub, unsub etc.):
>>>  http://mailman.qth.net/mailman/listinfo/elecraft   
>>> Help: http://mailman.qth.net/subscribers.htm
>>> Elecraft web page: http://www.elecraft.com
>>> ------------------------------------------------------------------------
>>>
>>>
>>> No virus found in this incoming message.
>>> Checked by AVG - http://www.avg.com Version: 8.0.176 / Virus Database:
>>> 270.10.14/1918 - Release Date: 1/27/2009 7:26 AM
>>>
>>>  
>>>      
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft   
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
> ------------------------------------------------------------------------
>
>
> No virus found in this incoming message.
> Checked by AVG - http://www.avg.com 
> Version: 8.0.176 / Virus Database: 270.10.15/1921 - Release Date: 1/28/2009 6:37 AM
>
>  

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