[time-nuts] HP 10811 update

[J. L. Trantham]

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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