[Elecraft] K2 Build Problem - No sidetone

[Sean Cavanaugh]

Thanks Don,

U8 was faulty only in that I missed soldering a pin, and missed it again 
while checking it with the lighted magnifier about 5 times. Clearly, I 
should be in bed. It's working now.


73,

Sean - VA5LF

On 12/03/2010 11:23 PM, Don Wilhelm wrote:
> Sean,
>
> U8 is seldom faulty. Check your soldering - refer to the Soldering
> tutorial on the Builder's resource page at the Elecraft website if you
> have questions. If suspicious, re-flow the soldering with a hot iron
> (750 to 800 deg F). The solder should flow out to an almost invisible
> edge on both the solder pad and the component lead. If it looks more
> like a ball on the solder lead, that is a sure sign that the solder pad
> did not receive enough heat. If there is a lot of solder on the
> connection, that can be just as bad because it masks a poor solder
> joint. Wick away the excess and re-solder. Strive to have only a small
> fillet of solder on each solder pad. Using a small diameter solder helps
> to control how much is applied. I use .015 diameter, but the .020
> diameter is usually OK with care. With larger solder diameters, by the
> time the solder flows, you already have too much solder on the connection.
>
> 73,
> Don W3FPR
>
> Sean Cavanaugh wrote:
>> Hi all,
>>
>> I'm building my K2. I've just got to the step where everything gets
>> assembled and tested for the first time, and when testing the sidetone
>> I'm getting nothing.
>>
>> I've set the K2 to edit St L and varied the value from 0 to 255,
>> checking the voltages on U8. Pin 1 is 0v for all settings, and pin 4
>> is also always 0v. The Vdd pin has 5.04v, and all ground pins show
>> connected to ground. It looks to me like U8 is bad.
>>
>> Any other ideas?
>>
>> Thanks es 73,
>>
>> Sean - VA5LF
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