[time-nuts] 5370B Question / help needed

Bob kb8tq kb8tq at n1k.org
Mon Jul 3 13:35:35 EDT 2017


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 <gary at 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.allgeier at gmail.com>
> Reply-To: 	Discussion of precise time and frequency measurement <time-nuts at febo.com>
> To: 	Discussion of precise time and frequency measurement <time-nuts at 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 at 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 at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



More information about the time-nuts mailing list