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

[Rice, Hugh (IPH Writing Systems)]

The 5061A/B is the only HP T&M product that I worked on deeply, and yes, the manual is very complete and accurate, save a typo here or there.    One careful reader (Ian) pointed out a typo in the generic 2N part number for the main TO-3 power transistor!

The product family was old enough that the service manual was effectively the master copy of the schematics, for both internal HP use and external use.   I have no memory of any official schematics stored or archived  anywhere else.   That may just be my bad memory though.  I'm sure I drew up schematics for my own designs, but don't remember "checking them in", or making official copies of them.

Official parts list, or bill of materials, were of course computerized by the 1980s, and drove the MRP (materials resource planning) process for purchasing components for manufacturing.

Hugh



From: time-nuts <time-nuts-bounces at lists.febo.com> On Behalf Of Adrian Godwin
Sent: Sunday, February 10, 2019 3:57 AM
To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
Subject: Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP

The schematics are so good - easy to read, lots of context. Even some
off-board parts shown so you can see where the signal ends up. Notes about
the function and adjustment. You can learn a lot from them. Manuals were
worth having.

So many of today's schematics are little more than a netlist : a bunch of
fragmented sections with no way to find how they link up (maybe net names
but you can't tell if they have 2 ends or several). Useless even for
troubleshooting, let alone education.


On Sat, Feb 9, 2019 at 6:08 PM Poul-Henning Kamp <phk at phk.freebsd.dk<mailto:phk at phk.freebsd.dk>> wrote:

> 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 ?
>
> --
> Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG<mailto:phk at FreeBSD.ORG> | TCP/IP since RFC 956
> FreeBSD committer | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
>
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