[time-nuts] HP 5370A Frequency counter Problem(s)

jshank j-shank at comcast.net
Wed Mar 21 21:30:29 EDT 2007


Could someone please provide me with a link or the procedure to disassemble, 
cleaned / lubed.
Thanks
Jeff
----- Original Message ----- 
From: "John Miles" <jmiles at pop.net>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Wednesday, March 21, 2007 7:43 PM
Subject: Re: [time-nuts] HP 5370A Frequency counter Problem(s)


> It's normal for those last few digits to bounce around when measuring
> frequency.  The shorter the gate time, the less-consistent the LSDs will 
> be.
> How do the tolerances compare to what's in the manual's self-check
> procedures?  You'll note that they don't tell you to expect 10.000 000 000
> MHz, but 10.000 000 0XX MHz.
>
> The important things to look at with a 5370 are: 1) verify that the 
> trigger
> levels are 0.00 +/- 0.01 with the controls set to PRESET; 2) verify that 
> the
> +T.I. ONLY interval is within 1 ns of 100.0 ns; and 3) verify that the
> jitter when measuring its own clock reference is less than 100 ps (all of
> the ones I have seen are under 50.)  If all of that is OK, then chances 
> are
> everything else will work properly including frequency measurement.
>
> I've found that many of them need their front-panel input assembly taken
> apart and the switches carefully cleaned/lubed.  That alone may clear up a
> lot of flakiness.  There have also been some reports of poorly-seated 
> ROMs,
> and/or socket contact problems.
>
> -- john, KE5FX
>
>
>>
>> I got a HP 5370A off of Ebay and although it looks terrible I thought it
>> would probably work OK.
>> But it doesn't :-(  I downloaded the manual and have yet to print it out.
>>
>> Question;
>> When doing a self check by feeding the 10 MHz from the back into the
>> counter it counts cycles OK
>> but the last 3 or 4 digits are erratic. I am starting to do as much
>> alignment as I can but am
>> wondering if this is a known problem and if a cure is known.
>>
>> Anyway I think I paid too much for this box of problems but will
>> continue to try to repair.
>>
>> Any suggestions (on repair only) is appreciated
>>
>> Bill K7NOM
>>
>
>
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