[time-nuts] UPDATE: HP 5300B - HP 5308A Counter Time Base...

Burt I. Weiner biwa at att.net
Sat Nov 1 20:39:00 EDT 2014

The closest it will adjust is -2.5 Hz of 10.0000 
MHz.  This unit differs from the one in the 
manual in that it has a Microsonics OCXO with the 
adjustment on the side of the module.  The oven 
does not feel warm but is written on the side is: 
"Adjust at 25 Deg C", which is about 77 degrees 
F.  The schematic associated with the oven is 
missing from the schematic.  I suspect that the 
oven is either shot or not getting power.  The 
unit will not power up with the boards separated 
so I'm going to have to spend some time hanging 
wires out the side to make measurements.  Does 
anyone know of a schematic showing the 
Microsonics module and the associated circuitry 
for oven control?  Not sure if it's worth the 
effort, but it would be a shame to toss it - that's against my nature.

Burt, K6OQK

>Tom & Bob,
>Thanks for the comments and quick reply.  Tom,
>when I originally did a  google search I did not
>see the site that you sent, but from your
>guidance I did find the manual showing the
>frequency adjustment and I'm letting the
>5300B/5308A combination counter heat up.  From a
>cold start it's about 6+ Hz low when compared to
>my house GPS reference - a DATUM 9390-52054.
>In a bit I'll give the thing a tweak and it
>should come right in as Bob suggests.  I don't
>know the history of this counter except that the
>fellow that gave it to me has nothing to really
>compare it against nor the experience to question
>its accuracy.  On my unit the oscillator
>adjustment marking is gone, but the hole for the
>adjustment thankfully is still there :>
>I'll let you know how it goes - should be a simple tweak.
>Thanks Guys,
>Burt K6OQK
> >From: "Tom Miller" <tmiller11147 at verizon.net>
> >Subject: Re: [time-nuts] HP 5300B - HP 5308A Counter Time Base
> >
> >Hi Bert,
> >
> >The service manual for the 5300B is on the keysight.com site under manuals.
> >
> >http://www.keysight.com/main/techSupport.jspx?s 
> earchT=5300B&id=5300B:epsg:pro&pageMode=OV&pid=5300B:epsg:pro&cc=US&lc=eng
> >
> >Do you have a frequency reference (house standard) that you can use to
> >adjust the reference in the counter? See the manual.
> >
> >Regards,
> >Tom
> >
> >From: "Burt I. Weiner" <biwa at att.net>
> >
> > >I was recently given a HP-5300B / 5308A counter. I thought it might be
> > >handy when I'm at an AM broadcast transmitter and need to make "rough"
> > >frequency measurements.  It turns out that at 1000 kHz it reads about 4.5
> > >Hz high. Looking inside I'm not sure if there's a time base adjustment.  I
> > >looked at the on-line manuals available and I don't find any reference to
> > >adjusting the time base frequency.  Does anyone here know anything about
> > >these counters?  Is there a schematic available?  I'm not looking for
> > >precision, but 4.5 Hz at 1 MHz seems a tad much.
> > >
> > > Burt, K6OQK
> > >
> >
> >------------------------------
> >
> >From: Bob Camp <kb8tq at n1k.org>
> >
> >Hi
> >
> >4.5 Hz at 1 MHz is 4.5 ppm. That’s not out of
> >the likely adjustment range on the basic crystal
> >reference on a 5308. It’s probably a simple
> >tweak to get it back into calibration.
> >
> >Bob

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
biwa at att.net

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