[time-nuts] Questions about HP 5370B

Bruce Griffiths bruce.griffiths at xtra.co.nz
Tue Sep 14 12:19:06 UTC 2010


It doesn't use IC regulators.
It uses a common IC reference together with a few opamps and discretes.

Bruce

Bob Camp wrote:
> Hi
>
> In an earlier thread on the 5370B checking the voltage out of the regulators was mentioned. If you are going to open the counter up anyway, putting a DVM on them is probably a good idea. They do run hot and some eventually drift way out of spec. Cheap part to replace if it's bad..
>
> Bob
>
>
>
> On Sep 14, 2010, at 3:12 AM, "Charles P. Steinmetz"<charles_steinmetz at lavabit.com>  wrote:
>
>    
>> A friend just received an HP 5370B that was said to be properly working and accurate, and asked my opinion.  I'm not familiar with these, so I thought I'd ask the experts.  All we've done so far is hook it to a Tbolt that I know is operating properly.
>>
>> The 5370B took hours (8 or so, which seems like a long time for a 10811) to drift to a reasonably stable reading, a bit over 100 Hz high (which seems like an awful lot for a 10811, even after a trip across the country ten years since its last calibration).  The front-panel oven indicator is off; I did not notice if it was on when we first powered it up.  The 5370B reads its own oscillator within spec (<  2 mHz error; spec is +/-5 mHz).  We have not opened it to tweak the oscillator (or to verify that the 10811 is, in fact, still present).
>>
>> Timing seems to work OK, giving the expected 100 nS and 50 nS figures when I feed the internal oscillator into the start input, tie start to stop (START COM), and switch the trigger phase of the stop channel.
>>
>> Finally, the external heatsink (left rear) runs pretty darn hot -- somewhat warmer than you'd really like to leave your hand on, which is WAY warmer than I'd ever design.  Concerning (to me), but not completely beyond reason.  I suppose it could be normal for these.  It didn't burn down or shut off during the 8 hour warmup.
>>
>> I appreciate any input from those knowledgeable about the 5370B.
>>
>> Thank you,
>>
>> Charles
>>
>>
>>
>> _______________________________________________
>> 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 mailing list