Hi If you go back in the archives a few years, there are extensive discussions of the various alignment steps on a 5070A or B. They are a highly recommend read if you are getting ready to dig into one of these counters.
Bob > On Jul 3, 2017, at 10:13 AM, Gary Neilson <g...@deepskyridge.com> wrote: > > I have a 5370B from ebay, it was missing a couple of boards and had a bad > interpolator card. Also a bad input hybrid on the stop channel. > > My unit acts similar to yours, TI measurement on the 10mhz signal shows 107 > ns. > > Frequency and Period measurement is spot on. > > I think it needs an alignment performed. I will get to that soon. > > Good Luck > > Gary - K5DSR > > > > -------- Forwarded Message -------- > Subject: [time-nuts] 5370B Question / help needed > Date: Sat, 1 Jul 2017 21:12:27 +0100 > From: Thomas Allgeier <th.allge...@gmail.com> > Reply-To: Discussion of precise time and frequency measurement > <time-nuts@febo.com> > To: Discussion of precise time and frequency measurement > <time-nuts@febo.com> > > > > I got hold of a 5370B cheaply but it turns out it may have a fault: > > Going through the motions of measuring TI with it's own 10MHz ref as input > (as described in the manual) I don't get 100 ns, but around 15 ns. So this > is with the switch set to START COM. Oddly enough I get the same 15 ns with > the switch set to SEP, and going through a 6 ft cable between start and > stop. > > Now I can "tune" the thing to display 100 ns by changing the trigger > levels. Start at 0.6 V and stop at -0.1 V will achieve this. Once again > this does not change by going from COM to SEP i,e. by adding the 6 ft delay. > > One other observation, probably related: After powerup it took several > vigorous switch activations of the COM/SEP switch before the thing swung > into action at all - i.e. the first reaction with COM setting was an Err > 02, and with SEP I got the 15 ns as described above. So that switch may be > a bit dodgy. > > Measuring in frequency mode gives the 10 MHz quite accurately, less than > 1mHz off with its own ref as stop input. Feeding the 10 MHz in from my > GPSDO also ties up OK, it is around 40mHz off with perhaps 5-10mHz jitter. > > Has anybody come across anything similar? I couldn't find much in that vein > in the archive but may have overlooked something. The one thing I was > worried about at first was the heat sinks at the rear getting really hot > but it seems I'm not the only one with that observation. > > To some extent it looks like the input levels for triggering are off, but > then the fact that the 6 ft cable don't show up as extra delay may mean > there is something else wrong. > > Looks like some "fun with Bill and Dave" lies ahead if somebody can point > me in the right direction. > > Thanks in advance, > Thomas. > _______________________________________________ > 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.