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

David Kirkby david.kirkby at onetel.net
Fri Apr 15 16:51:58 EDT 2005

jim_johnson at agilent.com wrote:
> 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.

I'm slightly lost there. You seem to be implying the B's have newer 
firmware than the A's, but then saying its not easy to tell if you have 
the new firmware, since the revision is the same. If the newer firmware 
was installed only in B's, then all you would need to do is look at the 
model number. Clearly then I assume either some B's have the old 
firmware, or some A's have the new firmware, or perhaps HP would update 
an A to a B firmware.

> 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). 

OK, it seems worth paying a bit more for a B. I have actually bought 
one, so are pleased I bought the B. I don't have it yet, so have no idea 
of S/N or anything.

> 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
> asterisk.

Mine is a B, so it should have the oven then.

>    So, that's about it - hope this was helpful.  Have
> a nice weekend!
> Regards,
> Jim
> 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.
>>>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,
> _______________________________________________
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> time-nuts at febo.com
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts

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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