[time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP

[Rice, Hugh (IPH Writing Systems)]

Hi Poul - 
I'm only familiar with the system design for the 5061A/B, and can't really speak to a general HP T&M design approach.  Maybe Rick has some insights.   
My real expertise is HP Inkjet printers, but those stories are for another mailing list.

Reaching back to the 5060A, I think Lou Mueller once told me that Len Cutler, in the original system design, decreed that every module would have "10dB of margin".    Not sure what that was compared to, but the idea is that he wanted a very reliable, very high margin design.   

The AC transformer in the 5061A/B was from HPs transformer organization (HP actually made their own transformers for many years), and whoever designed the original power system left a lot of "brown out" margin in the system.    There is a "115/230"  switch on the primary side of the transformer, but the system was designed to work well in low voltage 100 VAC countries.    The input AC voltage could go down quite a lot before the main 18.7V power throughout the 5061A/B would start to wilt.  

Hugh  



-----Original Message-----
From: Poul-Henning Kamp <phk at phk.freebsd.dk> 
Sent: Sunday, February 10, 2019 1:02 AM
To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>; Rice, Hugh (IPH Writing Systems) <hugh.rice at hp.com>
Cc: 'hughwr at yahoo.com' <hughwr at yahoo.com>
Subject: Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP

Hugh,

I notice your design, like all other HP designs I have seen from that era, operates with a very high margin for low mains voltage.

Do you happen to remember what HP's design criteria were for this ?

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Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
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