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

Fri Sep 19 09:52:09 EDT 2008

Jean-Francois,

Sounds like you are homing in on the problem.  Try removing the 
microprocessor and measuring the resistance between RP4 pins 5 and 6.  
If it is normal (81K), then you have a bad microprocessor input at pin 
30.  If so, replacement of U6 is the only solution I know about.

73,
Don W3FPR

Jean-François Ménard wrote:
> 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
>>>>
>>>>
>>>> ------------------------------------------------------------------------ 
>>>>
>>>>
>>>>
>>>> No virus found in this incoming message.
>>>> Checked by AVG - http://www.avg.com Version: 8.0.169 / Virus 
>>>> Database: 270.7.0/1680 - Release Date: 9/19/2008 8:25 AM
>>>>
>>>>
>>
>> ============================
>> De Jean-François Ménard / VA2SS
>>
>>
>>
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>
> ============================
> De Jean-François Ménard / VA2SS
>
>
>
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>
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