Wierd looking HP 3468A

[maxjenius]

Hello Everyone!

I've been following the EEVBlog for a few years, but this is my first post...I just purchased an HP 3468A from eBay and wanted to show you the guts...I've never seen anything like this before!

When I got it home, I immediately tested it and was getting no response from the input jacks, so I thought Whoo Hoo!, it's trouble shooting time!  The first weird thing about it was that it had an odd connector on top.  I had never seen this connection on any photos of it online...



When I opened it up, I saw that it had a completely seperate board on top labled "Ohms Converter".  Also, the two input jacks on the front panel were not connected at all!  It was routed to the top board.





So now I don't know what to do next...this threw me off, and now I want more info on it.  Anybody seen this version before?

P.S.  Happy New Year everyone!

[PedroDaGr8]

It almost looks like maybe they created their own scanner card. For scanning multiple items to test. I'm just guessing this based upon the large number of relays. Where does the ribbon cable go?


Sent from my EVO using Tapatalk

[maxjenius]

It sure does look like a custom job, interesting!  The ribbon cable connects to the main board near the power switch:





The power drawn to the board is bodged right on the main board on the +15V rail:



Very interesting...on a side note, I disconnected the input wires and connected them back on the input jacks, and the meter works perfectly

You can hear all those relays working when probing around...very curious as to what that board does, but yeah...definitely makes sense if it was used to automatically scan devices.