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

Scott McGrath scmcgrath at gmail.com
Sun Nov 2 01:00:16 EDT 2014

I've had a few of these over the years and option 001 is indeed a TCXO.  

Best bet for calibrating the TCXO is removing it from 5300B and tweak the osc on the bench

Also remember these were designed as service grade counters for land mobile service not lab grade instruments. There are battery and DVM modules available for these as well

This is a nice counter for radio service but it's not time nuts grade

Sent from my iPhone

> On Nov 1, 2014, at 11:39 PM, "Tom Miller" <tmiller11147 at verizon.net> wrote:
> 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
>> K6OQK
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