> 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.
