It's been 20 years, but I will try to recap what I remember
about this connector. I believe there were 3 customers,
and one of them required the DB connector with coax inserts
for reasons of backward compatibility. I think this
vendor was Motorola. We did not actually use the coax
inserts, but left them blank and ran the RF, etc on
ordinary pins. I believe you can make an ordinary male
DB-25 mate with these insert versions by clipping off some
of the pins that would be blocked by the female insert
version. I vaguely remember that the other 2 vendors
used gender changers or something. There might have
an issue with the mating plane location being different
for different customers.
I am sure that time-nuts, being talented at repurposing,
will be able to think about this problem and come up with
a simple solution to interfacing with these boards.
No need to buy insert type connectors. I never had
any trouble making cables that connected to these units
using plain vanilla DB25's.
Rick N6RK
On 4/15/2017 10:42 AM, Larry McDavid wrote:
Ok, so a standard DB 25-pin socket-contact connector will mate with the
on-board connector with the center hole and missing pins. That's good!
I now notice a comment on your webpages about this device in which you
mention a schematic. Do you have a schematic of this board? If so, can
you point to it or send me a copy.
I was unaware of the complete packaged unit on eBay; thanks for that.
Another poster mentioned the wiring of the connector on the full
instrument version power connector; is that pin-out and spec available?
Larry
On 4/15/2017 5:05 AM, Tom Van Baak wrote:
I purchased one of these HP E1938 OCXO recently on eBay but have not yet
received it.
Is that special D-Submin connector a receptacle-shell, pin contact
version? Will a standard plug-shell, socket contact 25-pin D-Submin
fit it?
Hi,
I'll cc the group here since we may get some useful comments.
I'm not exactly sure what you mean. The E1938A oscillators that I've
seen and tested look like this:
http://www.leapsecond.com/museum/e1938a/
And those can be interfaced with a simple D-sub DB25 connector on the
PCB. For connections, see that page, or any number of postings about
the E1938 in the time-nuts archives.
Note that on eBay there are at least three variations of E1938A
oscillator. The item#'s below are just random search picks (I have no
affiliation with any buyers or sellers) and I also know not all
surplus refurbished surplus recycled surplus stuff works. But we do
this because when they did work, they are sometimes totally amazing.
1) There's the bare "puck" alone, as in
http://www.ebay.com/itm/290829077542 -- and I have no idea where one
would start with that item since all the support circuitry on the PCB
would have to be re-created by hand.
2) There's the integrated PCB assembly, as in
http://www.ebay.com/itm/181043193416 -- which is more like what I tested.
3) There's the full instrument version, as in
http://www.ebay.com/itm/171293069062 -- which is most likely to work,
or be less hacked up, or dented, or salvaged, or rusted. It even has
all the connectors and power supplies, and GPS, etc.
If any other time nuts have experience with each of these methods to
obtain a E1938 oscillator, please let us know.
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