[time-nuts] HP5370B & HP5345B Front-End IC Redesign Effort
dalecan1 at cfl.rr.com
Sun Jan 24 13:34:02 UTC 2016
A friend asked me if I could replicate the front end for a 5370A, a many
years back. I related to him that replicating the input chip was not a
trivial task. His 5370A had been used (by someone else) for direct testing
of controlled-motion DC motors and the front end had obviously been
overstressed by voltage spiking. At the time, I had considered replicating
the front-end probe circuit of a K100D logic analyzer: FET diff. pair
followed by an ECL 10216 line driver. Obviously most daughterboard or dead
bug modification approaches have downsides; in the end I just couldn't cut
up the HP front end and told him to search for a more qualified repair
BAMA boat anchors has the K100D manual and probe schematic.
Dale Cannon KS4FA
From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Mathew
Sent: Friday, January 22, 2016 5:15 PM
To: time-nuts at febo.com
Subject: [time-nuts] HP5370B & HP5345B Front-End IC Redesign Effort
I was gifted an HP 5370B with the usual problem: front-end problems,
probably due to overstress. It is currently up and running again with a set
of 5345A series A3/A4 boards as I wasn't able to get a cheap pair of
5088-706x hybrid ICs.
This sounds like a common problem. As a result, I'm designing an open-source
drop-in (hopefully) replacement. My hat is off to the original IC designer,
as it is not a trivial effort due to the wide input signal common-mode
range, and very tight trigger timing requirements. Other items (like the
E-ECL) output) are also adding a bit of extra effort.
I'm hoping that someone(s) might be interested in working with me on it. I
would like to have my assumptions and math checked before I start the
detailed design phase, and perhaps contribute some better ideas.
In addition, it would be really helpful if someone could run a few rise-time
dispersion tests on an instrument with a working "B"-series A3/A4 PCB set
(my unit obviously doesn't qualify).
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