[time-nuts] HP 10811 update

Orin Eman orin.eman at gmail.com
Thu Jul 25 00:00:36 EDT 2013


I find it hard to believe that NTE spec the 123AP to replace a transistor
with min beta of 500...

This is quite entertaining:

http://www.vetco.net/catalog/product_info.php?products_id=1856

Look at the parts it's supposed to replace.

(Nothing against Vetco - they are a great source of NTE components and are
local to me.  They are just quoting what NTE claim.)

Orin.




On Wed, Jul 24, 2013 at 8:42 PM, J. L. Trantham <jltran at att.net> wrote:

> The 2N6429 crosses to an NTE123AP, in stock at Allied for $0.80.
>
>
> http://www.alliedelec.com/search/productdetail.aspx?SKU=70214870&mkwid=szEc5
>
> jMBI&pcrid=23468365337&pkw=nte123ap&pmt=e&pdv=c&gclid=CKyzu9_cybgCFWYV7AodJA
> sAWQ
>
> Good luck.
>
> Joe
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of paul swed
> Sent: Wednesday, July 24, 2013 8:29 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] HP 10811 update
>
> Well learned quite a bit Q4 does have an issue. Further there is a reason
> it
> has such high Beta. Its must deliver 30 ma to the oscillator and buffer.
> I was quite surprised by this current level. I was  guessing the oscillator
> was a few mils and the buffer maybe 8.
> The 2n3904 simply does not cut it. Need to do some digging in the ole
> transistors.
> Regards
> Paul.
>
>
> On Wed, Jul 24, 2013 at 8:06 PM, paul swed <paulswedb at gmail.com> wrote:
>
> > I can hope
> > I will embed a k thermocouple also.
> >
> >
> > On Wed, Jul 24, 2013 at 7:45 PM, Bob Camp <lists at rtty.us> wrote:
> >
> >> Hi
> >>
> >> The regulator should be fixed, and the OCXO will work better with it
> >> repaired. That said, shifting the regulated voltage from 5.7 to 5.27
> >> volts should not shift that oscillator 45 Hz.
> >>
> >> Bob
> >>
> >> On Jul 24, 2013, at 9:00 AM, paul swed <paulswedb at gmail.com> wrote:
> >>
> >> > Hello to the group. Numbers of threads running on the HP 10811.
> >> > Mine is
> >> 45
> >> > Hz low. The oven is most likely ok. I did get the can open per the
> >> various
> >> > other threads and the web pix. Started testing the circuits and
> >> > have
> >> found
> >> > that the regulator for the oscillator isn't. Its supposed to
> >> > produce
> >> 5.7V
> >> > and is at 5.27V thats pretty significant. The transistor looks like
> >> > a shorted collector base junction. Though I do not have it out of
> >> > circuit yet. Its Q4 a 2n6429. What interesting about this
> >> > transistor is its
> >> beta at
> >> > 1 ma is 500 min and max is 1300. Its not a darlington. Thats pretty
> >> > amazing. I am looking through my xsistors to find something close.
> >> > May
> >> just
> >> > through a 2n3904 in for a quick test. Its beta is nothing like the
> 6429.
> >> > But it would help to prove/disprove the point that the low V may be
> >> > offsetting the oscillator I hope.
> >> > Will also embed a K thermal couple to verify the oven really is in
> >> > the 80-84C region.
> >> > Regards
> >> > Paul.
> >> > WB8TSL
> >> > _______________________________________________
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> >
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