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

Tom Miller tmiller11147 at verizon.net
Sat Nov 1 23:39:47 EDT 2014

Bert, the normal oscillator is just a crystal. Option 001 is a TCXO, no 
oven. If you do not have opt 001, I would look for the second adjustment 
internally. Two are shown on the schematic.

----- Original Message ----- 
From: "Burt I. Weiner" <biwa at att.net>
To: <time-nuts at febo.com>
Sent: Saturday, November 01, 2014 8:39 PM
Subject: [time-nuts] UPDATE: HP 5300B - HP 5308A Counter Time Base...

> 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
> www.biwa.cc
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