[time-nuts] HP 106B quartz frequency standard...the story

[phil]

----- Original Message ----- 
From: "Dave M" <masondg44 at comcast.net>
To: <time-nuts at febo.com>
Sent: Monday, August 10, 2009 10:10 AM
Subject: Re: [time-nuts] HP 106B quartz frequency standard...the story


>> Thanks for that! - I do have a number of the 5254L units and one of
>> them is now being eyed off for organ donation. So thanks to all offers
>> for the 1854-0003.
>>
>> The 2N1701 in a T08 is my next quest...
>>
>> 2009/8/10 Dave M <masondg44 at comcast.net>:
>>>> Hi all,
>>>>
>>>> Latest update.
>>>>
>>>> With some help and phone calls from Bill the fault seems to have been
>>>> isolated. I have removed Q11 from inside the oven and it is cactus. Q9
>>>> is also very suspect so I'm going to replace that for good measure.
>>>>
>>>> Q9 is a 2N1701 in a T08 package. Thanks to various people I should be
>>>> able to track one down. Q11 is marked as 1854-0003 and that's an HP
>>>> internal number and all I know. Might have to substitute that one.
>>>>
>>>> After all this I have some quality photos and can knock up some good
>>>> descriptions of the repairs and the 106B internals if anyone is
>>>> interested. Any websites hanging around that want to take what I have?
>>>>
>>>> Regards and thanks to all!
>>>>
>>>> Jim Palfreyman
>>>>
>>>>
>>>
>>>
>>> Jim, the 1854-0003 is a pretty common HP part in older eqpt. ?If you 
>>> have
>>> junked 5245L counter handy, it's full of them, especially in the decade
>>> counter PCBs. ?If you don't have one handy, I have an assembly here with 
>>> 8
>>> of them on it. ?If you like, I can send it right away (if you're outside 
>>> the
>>> USA, you pay postage).
>>>
>>> Dave M
>>> masondg44 at comcast dot net
>>>
>>> I went to a bookstore and asked the saleswoman, "Where's the
>>> self-help section?" She said if she told me, it would defeat the
>>> purpose.
>>>
>
> Jim,
> The NTE sub for the 2N1701 is the NTE152, available from Mouser and many 
> other suppliers.  According to the datasheet, it's in a TO-220 case.  If 
> you want to try to find a sub in a smaller package, here are some of the 
> pertinent specs for the 2N1701.
> NPN Silicon
> Vcbo = 40V
> Ic (max) = 2.5A
> Pd = 25W
> Hfe = 20-80 @ 300ma/4V
> Vsat = 1.5V @ Ic=300ma, Ib=30ua
> Iceo = 750ua @ 60V
> Ft = 350KHz
>
> Dave M
> masondg44 at comcast dot net

I would not use a "cheap" general replacement transistor in a direct coupled 
unit unless it was absolutely positively the last one on earth. Many vendors 
have that 2N1701 in stock from 7 to 8 bucks American. We have repaired 
thousands (no exaggeration) of units that all that was wrong is where 
incompetent technicians used general replacement transistors rather than the 
originals in direct coupled amplifiers. 
http://store.americanmicrosemiconductor.com/2n1701.html

Phil