[time-nuts] HP 3458A ISOLATOR DTACK err @ pwr up

Ed Palmer ed_palmer at sasktel.net
Thu Jul 30 17:37:03 UTC 2009


Try putting a light load on the transformer when you measure the output 
voltage (maybe 1K).  You may find that terminals 2-3 are open circuit 
rather than short.  Maybe that's why CR10 survived - the transformer 
blew first.

Ed

Brooke Clarke wrote:
> Hi John:
>
> It's hard to say.  With the A4 Inguard p.s. board removed when powered 
> up the fan comes on and the display lights up with the error message.
>
> So, measured on the primary side, there's 25 ma AC current going to 
> the transformer then to the Outguard p.s. and fan.
>
> Have Fun,
>
> Brooke Clarke
> http://www.prc68.com
>
> J. Forster wrote:
>> Looks like it. Does the transformer draw much current with the PCB
>> removed? If it has shorted turns, as it appears, it likely will. Does it
>> get hot?
>>
>> -John
>>
>> =================
>>
>>
>>> Hi:
>>>
>>> I think the power transformer got cooked.  Have a look at the Vac 
>>> and Ohms
>>> data:  http://www.prc68.com/I/HP3458DVM.shtml#T1
>>>
>>> Force a browser refresh to see the latest schematic.
>>>
>>> Have Fun,
>>>
>>> Brooke Clarke
>>> http://www.prc68.com
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>>>
>>
>>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.




More information about the Time-nuts_lists.febo.com mailing list