Agilent/Keysight MSOX3024T LAN/VGA Module Fault - Causes?

[The_PCB_Guy]

I have created my own version of the LAN/VGA module designed for the X3000 series oscilloscopes form Agilent/Keysight. I had one version of the board working perfectly, though it had some mod wires. I did a respin of the board adding tracks to replace the mod wires, but now on power-up I am seeing a message on the screen which says "System concerns detected: LAN/VGA module fault". I don't have a screenshot at the moment, but it's just a very small window that pops up in the middle of the screen.

I know the problem exists on my board. There is absolutely no doubt about that. My question is, what sort of faults cause that error to appear? Shorts? Incorrect power rail voltages? Bad communication? Combination of issues? I am trying to narrow down what is wrong with my board, especially considering I had a similar one working just fine previously. I've checked my components, orientations, values, etc. so at this point I'm trying to narrow down where else the problem may exist.

To be clear, I am NOT asking what might be wrong with my board, and I am not necessarily seeking suggestions. I am simply wondering what triggers that error to appear on the screen of an X3000 scope. Hopefully this is clear.

Thank you very much,
Matt

[TheSteve]

With the DIY boards most people make(that don't have video at all) the fault occurs when the board is detected(a looped back pin) but it can't communicate with the FPGA. The fault is displayed in the boot log, so if nothing else you might need to connect to the console port and see if it gives a specific error. I have been wondering how your board has been coming along.

[The_PCB_Guy]

With the DIY boards most people make(that don't have video at all) the fault occurs when the board is detected(a looped back pin) but it can't communicate with the FPGA. The fault is displayed in the boot log, so if nothing else you might need to connect to the console port and see if it gives a specific error. I have been wondering how your board has been coming along.

Thank you very much for your reply, this is very helpful. I will have to remember how to connect to the console. I know I can use ethernet and telnet in, but I would prefer to connect via USB. This is possible, is it not? There is a Type B USB port on the rear of the scope, I just need to determine how to connect. Any suggestions?

Many thanks,
Matt

P.S. The HDMI is working on the modded board. I ordered a final set of PCBs and the parts to assemble two. The first one I assembled is the one I am having problems with. I wanted to prove it out before I build up the second one.

[TheSteve]

I only know you can telnet in using a network connection. From there you should be able to find the boot log info. I've never used the USB connection. For testing, the actual console port might be best, but that does require opening the scope and using a 3.3 volt serial to USB adapter or similar.

[The_PCB_Guy]

I only know you can telnet in using a network connection. From there you should be able to find the boot log info. I've never used the USB connection. For testing, the actual console port might be best, but that does require opening the scope and using a 3.3 volt serial to USB adapter or similar.

I see. I would definitely prefer to not open up the scope if at all possible. I was able to telnet into the scope but I have no idea where to search for the boot log, assuming it stores it somewhere.

[The_PCB_Guy]

UPDATE:

I was able to find the issue - upon further investigation, the power rails of the FPGA were not receiving their corresponding voltages (2.5V and 1.2V). It turns out that there were a couple of pins which were not properly soldered to the pads, and in fact sat slightly above them. Without all of the power rails, the FPGA did not operate properly, hence the scope displayed an error.

I was able to get the display working again, though now the colors are off. I suspect it's more poor solder joints on the HDMI transceiver chip. I will carry on solving that, but in the meantime thank you very much for your assistance!

Best wishes,
Matt

[TheSteve]

Very nice, I'm looking forward to further updates. If you decide to sell a kit that needs assembly I might be interested.

[The_PCB_Guy]

Very nice, I'm looking forward to further updates. If you decide to sell a kit that needs assembly I might be interested.

The current plan for sale (once complete) is as follows:

Option 1: Bare board + BOM
Option 2: Bare board + components
Option 3: Assembled board
Option 4: Assembled board with enclosure + faceplate

I have yet to determine pricing, though I do have a general idea. I will post here when the design is ready.

Best,
Matt

[Hexley]

Another "might be interested" party here. I'll be watching your thread for updates.

[tridentsx]

Did anything come out of this ?

[The_PCB_Guy]

Oh wow, I completely forgot about this thread! I got the board working to about 98%. I ended up with some faint pink vertical lines spaced out across the screen. I suspect either a timing issue, SI issue, or a combination of the two. After all, this was only a 6-layer board, meaning the inner two signal layers are not separated from one another. I would not be surprised if there was crosstalk between the signals. At some point I'll add two more internal ground planes and see if the problem goes away. Overall though, the DVI-D board works well. I can't call it "HDMI" because I'm not paying for the licensing.