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

Burt I. Weiner biwa at att.net
Sat Nov 1 23:33:41 EDT 2014


Bob,

Alas, I suspect you've hit the nail on the head.  I'll probably wind 
up replacing the oscillator with something similar that I can make 
work.  While I've got some pretty good counters in the racks in my 
workshop, the 5300B is a handy little counter to schlep around for 
low frequency work.  Beside, it's lighter than the rack mounted counters.

Thanks,

Burt, K6OQK

>From: Bob Camp <kb8tq at n1k.org>
>
>Hi
>
>If the OCXO was not heating, it would be off by about 20 to 60 Hz. 
>It's close enough that it is getting power and heating up. If it 
>does move when you fiddle the trimmer, that part is likely still connected.
>
>It sounds like the beast has simply aged further than it's trim range.
>
>Bob
>
> > On Nov 1, 2014, at 8:39 PM, Burt I. Weiner <biwa at att.net> wrote:
> >
> > 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
> >

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
biwa at att.net
www.biwa.cc
K6OQK 



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