[Elecraft] K2 freeze at startup... need advice

Fri Sep 19 09:43:11 EDT 2008

I also found another thing.....

Resistance check of Pin 7 and 8 of RP4 on the control board give me  
81K ohm, but PIN 5 and 6 give me 19K ohm... should be 81K ohm too !!!

Le 08-09-19 à 09:29, Jean-François Ménard a écrit :

> It seems that a resistence check on the control board give me a  
> hint..... U6 PIN 29 are inside spec, but PIN 30 give me only 16K ohm  
> and should be higher... around 80K ohm to 90k
>
> The key jack seems to be good, R1 and R2 are OK.
>
> Re-insert controler on RF board, nothing change
>
>
> Le 08-09-19 à 08:11, Don Wilhelm a écrit :
>
>> Jean-Francois,
>>
>> It certainly could be a faulty key jack, but it could be a  
>> microprocessor problem too.
>> Turn the power down to zero for further testing.
>> Then check the voltage at the end of R1 and R2  near the key jack -  
>> they are easy to reach if you remove the left side panel.  The  
>> voltage should be near 5 volts if there is nothing pulling those  
>> inputs down.
>> Remember that the DOT line and the PTT line are one and the same on  
>> the K2, so if that line is low the problem nay be in the key jack  
>> or on the Front Panel board.
>>
>> Should you find either the DOT or DASH lines near zero volts, turn  
>> power off and make resistance checks to find out if there is a  
>> short (maybe a solder bridge that has been dormant for a long  
>> time).  Those signal lines run direct to the microprocessor, so  
>> there is only the jacks, PC traces, and the microprocessor involved.
>>
>> 73,
>> Don W3FPR
>>
>>
>> Jean-François Ménard wrote:
>>> It seems that something let my K2 stuck in TX mode. I removed all  
>>> module and put appropriate jumpers (unmod kit). Still in TX when  
>>> powered ON. I checked this using my DL2 dummy load with my  
>>> multimeter.... I always have output power !!
>>>
>>> Could it be a defective KEY jack that is jammed? I have nothing  
>>> plugged......
>>>
>>>
>>> Le 08-09-18 à 23:33, Don Wilhelm a écrit :
>>>
>>>> Jean,
>>>>
>>>> This is strange - the second case of similar behavior reported on  
>>>> the reflector today.  Could it be a case of the 'phase of the  
>>>> moon'?
>>>>
>>>> When the K2 is in transmit state, the behavior will be as you  
>>>> describe - no buttons operate but the K2 displays the frequency.
>>>>
>>>> Check to see if your K2 is somehow stuck in transmit.  The  
>>>> easiest way is to check the state of the 8R and 8T voltages.  You  
>>>> can checkby measuring the DC voltage at the anodes of D6 and D7.   
>>>> During receive, the voltage at D6 anode should be about 8 volts  
>>>> and the voltage at D7 should be near zero volts.  If the K2 is  
>>>> 'stuck in transmit', those voltages will be reversed.
>>>>
>>>> If your K2 is indeed 'stuck in transmit', try removing the key  
>>>> plug and the microphone - if something external is creating that  
>>>> transmit condition, it should be OK with those cables unplugged.
>>>>
>>>> 73,
>>>> Don W3FPR
>>>>
>>>> Jean-François Ménard wrote:
>>>>>
>>>>>
>>>>> Hi everybody,
>>>>>
>>>>> I have my first major trouble since my building experience back  
>>>>> in 2004. Now, everytime i power up my K2, I can see ELECRAFT and  
>>>>> then the frequency..... but everything is frozen after......  
>>>>> still get the frequency displayed, but no button, no function  
>>>>> work. I also tried to reset the K2 to the factory default by  
>>>>> holding 4-5-6 buttons..... Got the 201 message then back to the  
>>>>> ELECRAFT and the frequency..... but still frozen !!!!
>>>>>
>>>>> Is it possible the the control board PIC got a static discharge  
>>>>> or something like this !?!?!?!
>>>>>
>>>
>>> ============================
>>> De Jean-François Ménard / VA2SS
>>>
>>>
>>> ------------------------------------------------------------------------
>>>
>>>
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>>>
>>>
>
> ============================
> De Jean-François Ménard / VA2SS
>
>
>
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============================
De Jean-François Ménard / VA2SS