[time-nuts] LPRO testing

[iovane at inwind.it]

Well, I believed to be answering questions from the original poster, not to 
questions that indeed are troubleshotting advices. Sorry....
Antonio
>
>Further, the strangest case I had to deal with was a correct voltage sweep 
at 
>the monitor output but wrong voltage at the varactor: the issue was a 
leaking 
>capacitor between the above voltage rail and ground, namely C406.
>
>Antonio I8IOV
>
>>
>>lists at rtty.us wrote:
>>
>>>The main questions on the lockup sweep is going to be:
>>>
>>>1) does it make it to / past the right frequency? 
>>>2) how soon after it does get there, does it lock up?
>>
>>It crosses the right frequency a few times until lockup, in both directions.
>>According to my experience, typical lockup time for a healthy unit is 3.5
min.
>>
>>>3) if it doesn't lock up, does it do something odd as it sweeps past the 
>>right frequency?
>>
>>It may get stuck at either end of the sweep span. Normally the sweept 
>voltage 
>>(as available at the voltage monitor output) should vary between about 0.5V 
>and 
>>12.5V and vice-versa. If it reaches 0V or about 14V then one of the voltage 
>>comparator circuits failed, and the unit gets stuck. 0.5V and 12.5V are 
>preset 
>>thresholds for the voltage comparators. I happened to come across both 
>cases, 
>>and the failing components were 100K resistors.
>>
>>Antonio I8IOV
>
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