Hi Ed,
I just tracked down Fluke and he offered me one, and per your advice I will
try and confirm the condition before purchasing from him (not that there are
alternate sources) . I have the schematics, but taking apart the hocky puck
is another matter, I pry and pry but get nowhere. I don't think it was
designed to take apart. What buggs me is that if I warm up the oven and
stimulate the oscillator with an external signal, it will oscillate. So it
DOES work, and if I go into the puck to trouble shoot it, I probably won't
find anything defective.
Bob
----- Original Message -----
From: "Ed Palmer" <[email protected]>
To: "Discussion of precise time and frequency measurement"
<[email protected]>
Sent: Sunday, January 08, 2012 10:07 PM
Subject: Re: [time-nuts] HP Z3817A Reverse Engineering
Hi Bob,
I bought mine on eBay from fluke.l for about $114 (including shipping). I
don't know if he has any more.
He didn't get positive feedback from me. His pictures showed a
reasonable, used unit. The unit he shipped was dented badly enough that
it was slightly crushed and appeared to have been out in the rain. It
does work, but the E1938 seems to be taking a long time to settle down. I
hope the crystal wasn't damaged when it took the hit that dented the case.
There is no physical damage to any of the boards. I've dealt with him
before and was surprised and disappointed that he didn't describe the
condition better. Buyer beware.
As for your 'lazy' E1938, have you grabbed the schematics and circuit
description from
http://www.prc68.com/I/HPE1938.shtml ?
Ed
On 1/8/2012 5:58 PM, Robert Benward wrote:
Hi Ed,
May I ask where did you get your STLN4096A and what you paid for it? Do
they have any more?
My E1938 recently crapped out. If I put a substitute 10MHz near the
first buffer, the PIC processor comes alive, then I can remove the 10MHz
and it begins to oscillate on it's own. I can quickly recycle power and
it still oscillates. Let it cool down and I need to repeat the
"stimulus" procedure. Anybody have any ideas?
Thanks,
Bob
----- Original Message ----- From: "Ed Palmer" <[email protected]>
To: "Time-Nuts" <[email protected]>
Sent: Sunday, January 08, 2012 12:20 PM
Subject: [time-nuts] HP Z3817A Reverse Engineering
I recently purchased a Motorola STLN4096A with the HP E1938A oscillator.
I bought it for the oscillator only.
Then I got intrigued by the HP Z3817A GPSDO that's included. I've
reverse engineered most of it and I've got it running. The 1 PPS is
really good ( 1000 measurements, Std. Dev. of <200 ps, min to max range
of <1.5 ns) and the HUP is very slowly dropping (currently at 13 us
after ~1.5 days) as the oscillator works out the kinks after it's long
sleep. It's dropping much slower than my Z3801A did when I first turned
it on.
There's one input that I haven't been able to figure out. I've got data
in and 1 PPS in from the GPS receiver. Everything seems to be working
so I'm at a loss what that the other input could be for. There are no
clues to it's function because it appears to go into one of the Xilinx
chips.
Does anyone have any more info on the unit? Has anyone figured out the
other input?
I have searched the net and the archives. There's very little info or
discussion on this unit.
Ed
_______________________________________________
time-nuts mailing list -- [email protected]
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
