Re: KX1 build issue after Part 1 of build

Posted by K9MA on Apr 28, 2016; 4:15pm
URL: http://elecraft.85.s1.nabble.com/KX1-build-issue-after-Part-1-of-build-tp7616877p7616888.html

I recently built a KX-1, and had the following problems (none of which
were my fault):

1.  Factory installed solder bridge on the DDS chip pins, shorting out
clock input.

2.  Bad DDS chip causing really bizarre behavior.  Unrelated to above
solder bridge and definitely not a bad connection.  Elecraft had never
seen that before.

3.  Bad solder joint on pre-installed surface mount mixer chip on
carrier board.

It works fine now.

Based on my experience, I would be very suspicious of every surface
mount IC connection.  Look at voltages and waveforms right at the
surface mount package lead.  Unfortunately, you need a microscope and a
very fine-tipped soldering iron to re-solder them, and it's very easy to
create new solder bridges.  Elecraft support suggested a piece of number
20 wire wrapped around the tip of a soldering iron.  I used a Metcal
soldering station, but replacing the DDS chip was still difficult.

73,

Scott  K9MA

On 4/28/2016 06:27, Don Wilhelm wrote:

> Frank,
>
> It sounds like the MCU is getting "mixed up".  Try doing a Reset to
> Factory Defaults.
> See page 69 in the manual.  It is a 2 step process.
> 1) Hold BAND and MENU together and power on - release the buttons
> after the LED test.  E09 should be displayed.
> 2) Turn power off, then back on and you should see E10.  Tap any switch.
>
> 73,
> Don W3FPR
>
>
> On 4/28/2016 3:01 AM, Frank Cox wrote:
>> (this is a repost after accidentally adding this to another thread)
>>
>> I'm building a KX1 and finished Part 1. I encountered problems during
>> testing.
>>
>> First I noticed when scrolling through the MENU items some some
>> segments of
>> the LED display don't light on some menu item names. However the same
>> segments will light on another menu item so it doesn't seem to be a
>> problem
>> with the display itself. Also, tuning with the encoder and band switch
>> displayed as expected.
>>
>> But now the display started going dark during tests and not coming
>> back on
>> after button clicks or encoder turns. When it does this the 5v and 6v
>> lines
>> still have correct voltages and nothing feels hot to the touch. The
>> only way
>> to get it to come back is to turn it off and wait a while.
>>
>> I've carefully checked parts placement and solder joints and can find no
>> problems so far, and it passes all the part 1 voltage tests.
>>
>>
>
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--
Scott Ellington  K9MA
Madison, Wisconsin, USA

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