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

jim_johnson at agilent.com jim_johnson at agilent.com
Fri Apr 15 13:16:19 EDT 2005

Hi again David,

   I talked to xxxxx this morning and here's what
he said:

The 5370B has a different processor board than the
"A" model, with on-board RAM (the "A" had a separate
RAM board).  The "B" has had an upgrade to its DAC
board.  The "B" has a different input module that is
more stable than in the "A".  The firmware has had an
upgrade in the "B", as the HPIB (GPIB) would occasionally
hang up in the "A" model.  The bad news is that the
newer firmware carries the same rev. number as the old one
so you can't easily tell which one you have installed.
Very early units of the "A" model had non-ovenized 
oscillators in them.  Later versions had the ovenized
HP 10544 oscillator, followed by the newer HP 10811
oscillator, and it is believed that all "B" models have
the 10811 oscillator (ovenized).  In an "A", it is easy
to tell whether you have an ovenized oscillator or not.
Turn the counter off for a couple of minutes and then
re-apply power.  All units with ovenized oscillators in
them will show an asterisk on the front panel, indicating
the oven is warming up.  The non-ovenized units have no

   So, that's about it - hope this was helpful.  Have
a nice weekend!

Agilent Laboratories
Palo Alto, CA

>-----Original Message-----
>From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
>Behalf Of David Kirkby
>Sent: Thursday, April 14, 2005 10:22 PM
>To: Discussion of precise time and frequency measurement
>Subject: Re: [time-nuts] Difference between HP 5370A and 5370B
>Thanks a lot Jim.
>I was thinking of buying one. Although the 5370B seems a bit more 
>expensive, there does seem to be a lot more information on 
>them around, 
>which is a definite advantage.
>When you speak to xxxxx, I'd like to know if these have ovens as 
>standard, or whether that is an optional extra.
>jim_johnson at agilent.com wrote:
>> Hi David,
>>    I will check with another guy tomorrow (the last
>> surviving technician), but one person "in the know" 
>> has this to say:
>> ================================================================
>> What I remember is the input amplifiers are very different. 
>> As a result, some of the boards and pots and switches associated 
>> with it are different.
>> I don't remember any significant differences beside that.
>> My recommendation for someone buying one through eBay is, whereas 
>> it is hard to get replacement parts for both, getting parts for 
>> A is much harder.
>> Try talking to (xxxxxxx) who is the last surviving technician 
>> familiar with the product.
>> =================================================================
>>    If I find out any more details, I'll post them.  There
>> are a lot of sharp experimenters out there who may know
>> the answer and will get it to you before I do.
>> Regards,
>> Jim Johnson
>> Agilent Laboratories
>> Palo Alto, CA
>> jim_johnson at agilent.com
>> ====================================================================
>>>-----Original Message-----
>>>From: time-nuts-bounces at febo.com 
[mailto:time-nuts-bounces at febo.com]On
>>Behalf Of David Kirkby
>>Sent: Thursday, April 14, 2005 3:32 PM
>>To: time-nuts at febo.com
>>Subject: [time-nuts] Difference between HP 5370A and 5370B time
>>Can anyone tell me what is the difference between the above two 
>>Does anyone have any operating manuals in electronic format?
>>Dr. David Kirkby,

More information about the time-nuts mailing list