OverviewOne day i turn on my big Infiniium scope and all i get is fans running and a black screen. Uh oh...
I power cycle it, remove the mains for a few seconds, remove it for a few minutes... Sometimes the scope would show a blinking cursor on a black screen, sometimes nothing. It never makes a BIOS boot beep or show any actual bios text, once i even got it to show this:
Something is clearly very wrong with my scope. So off goes the cover for the first time on this scope. Its pretty easy to get inside, just remove all the visible screws, slide off the plastic, again remove all visible screws on the back and slide off the metal cover and we are in.
The design is actually quite compact seeing what they had to fit in here. The seemingly empty space to the right of the motherboard is taken up by the two large fans that are attached to the metal back cover(Wires for the fans running off to the right).
The construction is made up in layers from front to back:
-Front panel+LCD
-Acquisition board
-PSU + Cooling ducts
-Embeded motherboard + main fans
Interestingly the entire scope runs from 12V and with the typical 300 to 400W power draw of this scope that means a lot of current on that single 12V rail. This is why the two cables coming out of the PSU are so massive. Each wire as thick as a mains cord, while the thin wires coming off the terminals might look like sense wires, but they are actually powering the PC Motherboard (They only look thin in comparison). The actual PSU brick in there is rated for 750W. The same brick also provides standby 5V over the tiny black wires.
TroubleshootingAll the other rails that the motherboard needs are created by the acquisition board and then fed to it via a standard 24pin ATX power connector. So first things first, thou shall measure voltages... and all the rails turn out to be there and stable, the powergood wire also does what it is supposed to. So its not a power issue and the problem could be the motherboard itself.
Then perhaps something is preventing the board from booting. So i disconnect everything from the motherboard. This means disconnecting the hard drive, USB (Used by the front panel) and the SATA cables going to the acquisition board. Still no change. So now i remove the motherboard from the scope and hook it up to the PSU of a test PC, still no boot. So indeed the embedded PC is indeed dead.
So why is the board not booting then. I tried removing RAM sticks, did nothing. I moved the Core 2 Duo CPU into my 775 socket test PC and it booted fine so the CPU works. So yes indeed the motherboard itself is dead, no way around it.
The solutionGetting your hands on a replacement board is actually quite tough tho. The board is a "Adlink M-890-Raptor" and its that last part of the name that is the problem. The name "Raptor" is actually a internal Agilent codename for the Infiniium 9000 series (Most Infiniium scopes are codenamed after dinosaurs for some reason, perhaps due to the size and heft of these scopes). This means this is a custom motherboard made for Agilent. To make things worse Keysight will not sell you the board, but requires the scope to be sent in for service, this is likely because of the Windows 7 license activation and scopes needing a new hard drive image upon motherboard change (There are 3 different motherboards available, some run Win XP). So your only hope in getting your hands on a spare board is ebay or cannibalizing a donor scope.
Adlink actually used to manufacture a similar board with the same specs and form factor, but has the custom Agilent features removed, thus making it not entirely compatible.
The 3GHz Core 2 Duo is getting pretty dated these days, so if we are changing the motherboard we might as well also upgrade it. Keysight has a new board for Infiniium scopes that runs a modern i5 processor on it, however just like the original board its not possible to buy it. I was actually thinking of this upgrade before my scope died, and happened to stumble upon the "ASRock IMB-181-L" for cheap and bought it.
This board is a slightly smaller ITX form factor (Less PCI slots) than the original but all the screw holes still match up. It takes much more modern Intel Haswell processors in its 1150 socket, but most importantly it has LVDS video output, this can be used to drive the LCD panel directly.