[Elecraft] Kx1 Z1 Encoder testing

[Don Wilhelm]

Burke,

That indicates that  Z1 has a high resistance connection - it could be 
inside Z1 (faulty Z1) or it could be in your soldering.  Check (and 
re-flow) the soldering at U1 pins 3 and 4, RP3 pins 3, 4, 5, 6, 7, 8, 9 
and 10 and pins 1, 2 and 3 of Z1.  If that does not fix it, blame Z1.

73,
Don W3FPR

Burke Jones wrote:
> Okay. Here is what happens. I was lucky when I turned it on to check  
> it was having problems because it sometimes works right.
>
> The display showed .8 and 0 volts. I would turn it and it would go to  
> 4.89 volts and the display would change to .9 and the voltage would  
> stay at 4.89 until I turned it a bit. Then the display would change  
> to .8 and the voltage would be 0.
>
> It would just repeat this over and over everytime I turned z1 a bit.
>
> Then it started working and the voltage would be 0 until I turned it  
> and it would go up into the 5 volt range and then back to 0 when I  
> stopped turning it.
>
> Does that seem to indicate a z1 that is faulty sometimes?
>
> Burke Jones
> Sent from my iPhone
>
> On Mar 14, 2009, at 7:37 PM, Don Wilhelm <w3fpr at embarqmail.com> wrote:
>
>   
>> Burke,
>>
>> Yes, you can test the encoder and its circuit to the microprocessor  
>> with a DMM.
>> Measure the voltage from the encoder pins as you slowly rotate the  
>> encoder shaft.  The outer two pins in the row of 3 are the ones to  
>> measure.  As you rotate the shaft, the voltage should jump between  
>> zero volts and something close to 5 volts.  If it does not go to  
>> zero, there is a problem with the encoder.
>> If the voltage does not go up to the vicinity of 5 volts, look  
>> carefully at RP3 and U1 pins 3 and 4.
>>
>> If that does not reveal a problem, I can give you some resistance  
>> checks to make too.
>>
>> 73,
>> Don W3FPR
>>
>> Burke Jones wrote:
>>     
>>> I am almost done with my KX1. During each test section I have  
>>> noticed  that there seems to be a problem. Sometimes turning Z1  
>>> changes the  frequency display but sometimes when you turn it the  
>>> last 2 digits on  the display just go back and fourth - like from 1  
>>> to 2 then 1 then 2.
>>>
>>> I have triple checked the solder connections at Z1.
>>>
>>> I am trying to figure out if I might have a faulty Z1 encoder. Can   
>>> anyone tell me how I could use my DMM to test directly at the  
>>> "leads"  of the Z1?  If so which leads and what should I look for?
>>>
>>> Thanks for all your help!!
>>>
>>> Burke Jones
>>> N0HYD
>>> Http://www.n0hyd.com
>>>
>>> Sent from my iPhone
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