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

[Jean-François Ménard]

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
>>
>>
>> ------------------------------------------------------------------------
>>
>>
>> No virus found in this incoming message.
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>>
>>

============================
De Jean-François Ménard / VA2SS