Look at the interrupt lines going to the micro. They are always a good clue. If you see a repeating interrupt at the same rate that may give you guidance.
On Tue, Dec 18, 2012 at 4:27 AM, Ulrich Bangert <df...@ulrich-bangert.de>wrote: > > You tie the reset through a 1 K r to vcc and you still see > > the reset signal? > > Yes! > > > And you do not see the 7 Khz coming from > > the switching regulator?? > > No, it is clearly the line that has its source in the LM2925 5V regulator. > Note however it MAY BE that an active reset behind the lowpass is an > allowed > condition even if it does not originate from the LM2925. The 1 K may be > kind > of "decoupling" allowing the micro to reset itself AND U501 on its own, say > watchdog or, without being "shorted" by the LM2925. So the fact that there > are reset pulses not coming from the LM2925 are not as spectacular as the > question WHY they are there. > > Best regards > Ulrich Bangert > > > -----Ursprungliche Nachricht----- > > Von: time-nuts-boun...@febo.com > > [mailto:time-nuts-boun...@febo.com] Im Auftrag von paul swed > > Gesendet: Montag, 17. Dezember 2012 15:12 > > An: Discussion of precise time and frequency measurement > > Betreff: Re: [time-nuts] OT: Question on dead HP34401 > > > > > > So we are on the same page > > You tie the reset through a 1 K r to vcc and you still see > > the reset signal? And you do not see the 7 Khz coming from > > the switching regulator?? Thanks > > > > On Mon, Dec 17, 2012 at 2:57 AM, Ulrich Bangert > > <df...@ulrich-bangert.de>wrote: > > > > > Gentlemem, > > > > > > pardon for the delayed answer, I had some extreme busy days > > the last > > > week. > > > > > > > The floating logic is reset by the LM2925 5V regulator > > reset output. > > > > There is no connection to this reset line aprt from the > > Gate array > > > > reset input and the micro (80196) reset input. > > > > > > Yes, U553 on page 9-15 has this reset output which is > > called XPONRST. > > > After it has passed the lowpass R503/C504 on page 9-13 > > (upper left) it > > > enters U500 and U501. I observe this 7 kHz reset signal > > RIGHT from the > > > lowpass even if I > > > lift up the voltage regulator's reset output pin. > > > > > > Best regards > > > Ulrich Bangert > > > > > > > -----Ursprungliche Nachricht----- > > > > Von: time-nuts-boun...@febo.com > > [mailto:time-nuts-boun...@febo.com] > > > > Im Auftrag von Bruce Griffiths > > > > Gesendet: Dienstag, 11. Dezember 2012 22:46 > > > > An: Discussion of precise time and frequency measurement > > > > Betreff: Re: [time-nuts] OT: Question on dead HP34401 > > > > > > > > > > > > It only resets the earth referenced micro (8051) on power up and > > > > when pulses on the optocoupler output arent present. There is no > > > > other connection to the reset pin of this micro. > > > > > > > > The floating logic is reset by the LM2925 5V regulator > > reset output. > > > > There is no connection to this reset line aprt from the > > Gate array > > > > reset input and the micro (80196) reset input. > > > > > > > > The relay drivers are reset by a 80196 output pin. > > > > > > > > The display logic is reset by another 90196 output pin. > > > > > > > > Bruce > > > > > > > > paul swed wrote: > > > > > OK but why would it tie to the reset line? > > > > > > > > > > On Tue, Dec 11, 2012 at 3:48 PM, Marco IK1ODO > > > > -2<ik1...@spin-it.com> > > > > > wrote: > > > > > > > > > > > > > > >> At 21:40 11/12/2012, you wrote: > > > > >> > > > > >> > > > > >>> Two comments the manuals available on agilent > > > > >>> What on earth is a crossguard? > > > > >>> > > > > >>> > > > > >> Data exchange between a floating, guarded circuit and a ground > > > > >> referenced one? > > > > >> > > > > >> Marco IK1ODO > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> ______________________________**_________________ > > > > >> time-nuts mailing list -- time-nuts@febo.com > > > > >> To unsubscribe, go to https://www.febo.com/cgi-bin/** > > > > >> > > > > > > mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/list > > > > i > > > > >> nfo/time-nuts> > > > > >> and follow the instructions there. > > > > >> > > > > >> > > > > > _______________________________________________ > > > > > time-nuts mailing list -- time-nuts@febo.com > > > > > To unsubscribe, go to > > > > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > > > and follow the instructions there. > > > > > > > > > > > > > > > > > > > > > > _______________________________________________ > > > > time-nuts mailing list -- time-nuts@febo.com > > > > To unsubscribe, go to > > > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > > and follow the instructions there. > > > > > > > > > _______________________________________________ > > > time-nuts mailing list -- time-nuts@febo.com > > > To unsubscribe, go to > > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > and follow the instructions there. > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
