[time-nuts] Difference between HP 5370A and 5370B

David Kirkby david.kirkby at onetel.net
Sun Apr 17 07:35:13 EDT 2005

John Ackermann N8UR wrote:
> David Kirkby wrote:

>> I know know the S/N of this unit, although I don't have it yet. The 
>> S/N of the 5370B is 2904A02491. If anyone is able to determine the 
>> date (and/or part number) of the manual that will cover this S/N, I 
>> would like to know.

> Hi David --
> The first four digits of an HP serial number tell you the revision level 
> -- the first two numbers plus 60 are the year (ie, 29 is 1989, quite 
> late for a 5370), 

That is good to know. I assume there are less bugs in the late versions.

> while the last two digits are either the week or a 
> series number, I'm not sure which.  These digits only guarantee that 
> your unit was built after that date, but they are a good guide to 
> relative lateness. 


> HP manual changes are keyed to that four-digit 
> series.  Usually, new manual editions come out fairly infrequently, and 
> they include change pages showing all the series changes up to the 
> version shown in the manual.  But in reality, the changes are generally 
> pretty small and I usually don't worry much about matching up the series 
> number unless I have serious repair work in front of me. 

Someone did send me an email, saying he felt it was more important on 
this particular instrument than normal to get the manual matching the 
serial number, as there were significant changes. He did need to do some 
repair work and found the changes very important. Given the age of this 
equipment, and (unlike modern stuff) you have some hope of being able to 
repair it, getting the latest information seems wise, if it is possible.

Dr. David Kirkby,

Please check out http://www.g8wrb.org/
of if you live in Essex http://www.southminster-branch-line.org.uk/

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