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

paul swed paulswedb at gmail.com
Mon Jan 25 16:28:35 UTC 2016 

Hello to the group.
Lots to learn. eecl? :-) Heck happy to get ecl working.
That said I did pull the manuals on the 5370 and 5345. They are the same
front end. And really 1 magical chip.

OK now I am going to super over simplify the issue. Forgetting the nice
features, why wouldn't the first step be to simply create a sine to square
wave converter?
But a dead frontend makes the counter useless. So getting a signal past it
is useful even if its not the exact quality of what existed.

Does that simplify at least the first possible answer.
Regards
Paul
WB8TSL.

On Mon, Jan 25, 2016 at 10:32 AM, 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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