[time-nuts] OT: Question on dead HP34401

Bruce Griffiths bruce.griffiths at xtra.co.nz
Tue Dec 11 21:45:59 UTC 2012


It only resets the earth referenced micro (8051) on power up and when 
pulses on the optocoupler output arent present.
There is no other connection to the reset pin of this micro.

The floating logic is reset by the LM2925 5V regulator reset output.
There is no connection to this reset line aprt from the Gate array reset 
input and the micro (80196) reset input.

The relay drivers are reset by a 80196 output pin.

The display logic is reset by another 90196 output pin.

Bruce

paul swed wrote:
> OK but why would it tie to the reset line?
>
> On Tue, Dec 11, 2012 at 3:48 PM, Marco IK1ODO -2<ik1odo at spin-it.com>  wrote:
>
>    
>> At 21:40 11/12/2012, you wrote:
>>
>>      
>>> Two comments the manuals available on agilent
>>> What on earth is a crossguard?
>>>
>>>        
>> Data exchange between a floating, guarded circuit and a ground referenced
>> one?
>>
>> Marco IK1ODO
>>
>>
>>
>>
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