HP 8568A spectrum analyser - UK Vintage Radio Repair and Restoration Discussion Forum

woodchips · 12th Jul 2019, 11:41 am

This just fell off the pile so thought I would look at it.

Very first problem is the interconnect cables. I do have a pair of genuine cables which were removed from a military test cabin so must be as new and unmoved as is possible. The SA was bolted into the rack and sure it never got moved from the day it was installed to the day it was scrapped, they just left the cables in the rack.

But the 50 way cable to the CPU card in the RF section doesn't plug fully in. The design is such that the socket is soldered to the PCB, with special nuts for the strain relief screws. There is then a 1mm or so panel between these screws and the front face of the cable connector. With the PCB out then the cable plugs firmly into the socket, but with the extra panel thickness it doesn't. These are standard Cinch connectors. Do the socket contacts slowly get bent back so they no longer make contact? A search turns up others who have noticed this. Do I have to replace the socket to get the SA working?

The snag is they are so heavy that in my advanced state of decreptitude it quickly becomes a nuisance to keep moving them. And this, of course, puts immense strain on the cables, and slowly ruins them.

I only have the manual set for the 8566A, and the RF part is very different. And the sections for the CPU and memory are missing, even though the very expensive manuals were bought as complete.

12th Jul 2019, 11:41 am	#1
woodchips Octode Join Date: May 2010 Location: Grantham, Lincolnshire, UK. Posts: 1,174	HP 8568A spectrum analyser This just fell off the pile so thought I would look at it. Very first problem is the interconnect cables. I do have a pair of genuine cables which were removed from a military test cabin so must be as new and unmoved as is possible. The SA was bolted into the rack and sure it never got moved from the day it was installed to the day it was scrapped, they just left the cables in the rack. But the 50 way cable to the CPU card in the RF section doesn't plug fully in. The design is such that the socket is soldered to the PCB, with special nuts for the strain relief screws. There is then a 1mm or so panel between these screws and the front face of the cable connector. With the PCB out then the cable plugs firmly into the socket, but with the extra panel thickness it doesn't. These are standard Cinch connectors. Do the socket contacts slowly get bent back so they no longer make contact? A search turns up others who have noticed this. Do I have to replace the socket to get the SA working? The snag is they are so heavy that in my advanced state of decreptitude it quickly becomes a nuisance to keep moving them. And this, of course, puts immense strain on the cables, and slowly ruins them. I only have the manual set for the 8566A, and the RF part is very different. And the sections for the CPU and memory are missing, even though the very expensive manuals were bought as complete.