[time-nuts] HP 10811 update

J. L. Trantham jltran at att.net
Thu Jul 25 09:50:06 EDT 2013


Very interesting list.

I wonder if that is a way to identify a cross from a manufacturer's P/N
(Tek, HP, Fluke, etc.) to a 'real' part?

Either that or all you need is a collection of NTE parts and never anything
else :).

I have used NTE parts to cross to 'unobtanium' in the past and, so far, it's
worked.  However, my first choice is a 'new' item followed by 'NOS' followed
by 'used' then 'anything that will work'.

Joe

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Orin Eman
Sent: Wednesday, July 24, 2013 11:01 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] HP 10811 update

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_cybgCFWYV
> 7AodJA
> 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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