[Elecraft] VOX Lockup

[Stewart Baker]

John,

If you are on PTT and have the PTT pressed then the voltage on U4 pin 3 will be 
< 0.6v.

If the voltage on U2 pin 2 is around 2.2v then when VOX operation is selected  
then PIC U1 measures this voltage from the COMP OUT signal on U1 pin 3 and 
commands the DAC U2 to output a similar voltage to U4 pin 3. i.e 2.2v.

I would check that the voltage on U1 pin 3 is the same as on U4 pin 2.
If that is OK, then check all the soldered connections between U1 and U2.

Then I would look at replacing U2 as it does not seem to be giving out the 
correct levels either for PTT (0.8V vs 0.6V), or for VOX (3.1V vs 2.2V).

Hope this helps

73
Stewart G3RXQ




On Sat, 7 Jan 2006 09:55:28 -0500, John Huffman wrote:
> Stewart -
>
> Remeasured.  Between pins 2 and 3 I get 3.6v.  But, if I press and release the
> PTT, it goes to .8v.  It remains at .8v regardless of SSBA setting.
>
> 73 de NA8M
> John
>
>> Please re-measure the voltagesBETWEEN pins 2 and 3 on U4.