[time-nuts] HP5370B & HP5345B Front-End IC Redesign Effort

Clint Jay cjaysharp at gmail.com
Mon Jan 25 11:33:56 EST 2016


I would imagine it was much less expensive for HP to gut second hand
equipment and re-qualify it than restart a fab or qualify a new design
front end.
On 25 Jan 2016 16:01, "Bert Kehren via time-nuts" <time-nuts at febo.com>
wrote:

> Getting back to the original question, years ago I was told but could not
> confirm that HP was buying up 5345's because of a Government commitment to
> replace front ends. If they had to go to such matters I doubt we will be
> able to  find a solution.
> In my home counter work I tried but ended up using boards out of  5345's
> Bert Kehren
>
>
> In a message dated 1/25/2016 10:01:18 A.M. Eastern Standard Time,
> bruce.griffiths at xtra.co.nz writes:
>
> I've  been considering this for some time.The key is the replacement for
> the  triggered phase locked oscillator based interpolators.
> FPGA based TDCs  aren't yet quite good enough.
> Off the shelf TDC chips are a little better  but still fall a little short
> in performance.
>
> Whilst a TAC approach can  achieve around 4ps or so (eg various Wavecrest
> instruments) a lot of discrete  parts are  likely to be required.
>
> My crude testing of a triggered  damped sinewave generator sampled by an RF
> ADC indicates that an event time  stamp noise of 5ps or better appears
> feasible.
>
> The technique of  exciting a high Q saw bandpass filter with an impulse and
> digitising  the  output is probably more expensive and complex than
> desirable.
>
> Bruce
>
>
> On Monday, 25 January 2016  6:04 PM, Bob Camp <kb8tq at n1k.org> wrote:
>
>
> Hi
>
> Since the  front end chips are mixed signal ASIC’s, it will take more than
> a bit of time  to
> replace them directly. Re-doing the entire front panel board is the  most
> likely way to “fix”
> the problem. The question is - why do that at all?  Just do a PC instrument
> that does the same
> thing as the counter with way  less effort…..
>
> Bob
>
>
> > On Jan 24, 2016, at 6:02 PM,  Dimitri.p <dimitri at dotp.com> wrote:
> >
> > Someday , someone  will get bored with everything else and give it a try,
> you know, in their  spare time.
> > The time when these counter were new was a long while  ago.
> > Back then an amplifier chip with 500MHZ BW was a much bigger deal  than
> it is in 2016.
> > ...but spare time is permanently on backorder ....  :)
> >
> > Dimitri
> >
> > At 06:15 AM 1/24/2016, Bob Camp  wrote:
> >> Hi
> >>
> >> Back when these counters (5345,  5370, 5335) all were new, the inputs
> were
> >> the weak link on all of  them. There were known âdonât do thatâ things
> on the line
> >> that  would blow out each of them. Regardless of the level of care and
> yelling,  inputs
> >> blew on a fairly regular basis. Probably 10% of the  counters went back
> >> for repair over a 5 year period. It was always  a âswap out the entire
> boardâ sort
> >> of repair and never was under  $1K. We regularly spent the price of a
> new counter
> >> each year on  repairs. If there had been an easy way to fix them,  (or
> even to  just
> >> pay $500 for the chip) we would have done it.
> >>
> >> Bob
> >>
> >> > On Jan 24, 2016, at 8:34 AM,  Dale Cannon <dalecan1 at cfl.rr.com>
> wrote:
> >> >
> >>  > Funny,
> >> >
> >> > 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
> >> > facility.
> >> >
> >> >  BAMA boat anchors has the K100D manual and probe schematic.
> >>  >
> >> >              Dale  Cannon  KS4FA
> >> >
> >> >
> >> >  -----Original Message-----
> >> > From: time-nuts  [mailto:time-nuts-bounces at febo.com] On Behalf Of
> Mathew
> >> >  Breton
> >> > 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).
> >> > Regards,
> >> > Mat  Breton
> >> >  _______________________________________________
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