hp 1820-7730 datasheet? HP-PB J2146A LAN interface, SOT23 part missing

Arno Kletzander Arno_1983 at gmx.de
Thu May 21 09:44:49 CDT 2015

Hello Folks,

with a bunch of HP 9000 equipment, I received a HP-PB "802.3 10Mbps LAN" 
card that was missing the 10base2 BNC connector and the SOT23 SMD part
directly behind it. No idea why and by whom they were removed. A BNC
socket was easily found in one of my parts bins, but what about the
SMD component? My first idea was this might just be some sort of
transient protection device (I've seen a really old ISA NIC fitted with
a neon bulb next to the BNC for that purpose!) but there probably is a
bit more to it, as pin 1 connects to BNC Center and to pin 7 on the PHY
(U18, NatSemi SS9130AP also HP house-marked as 1820-7730), pin 2 is BNC
shield/ground *and pin 3 goes to pin 5 on the PHY*.

Unfortunately I was not able to find a datasheet for the PHY that would
probably give an example circuit - can anyone please either point me to
that or, if they have an example of that card available, look up the
marking of that SOT23 device for me?

Card would be for my HP9000-K100 PA-RISC, for which I'm also looking 
for one of the graphic options. One keeps popping up in the US 'bay
but the (commercial) seller wants real money for it - add S&H to old
europe and it's waaay out of my confortable range.

Thanks in advance,


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