I also have the very same symptom after installing the latest F/W UFX:360 dated 02/20/2019 on my FF UFX. White LCD display and State LEDs on solid after F/W update and power cycle.
This does sound like a F/W issue Matthias.
I am an electronic engineer and I have done some troubleshooting and need some technical support. Here is what I have done.
My FF800 PSU connected to my FF UFX causes the UFX to behave in the same manor. All white LCD Display with State LED's on solid. The DC voltages on the two molex connectors located on the PCB that has the Spartan FPGA, & TI DRAM are the same when using the FF800 PSU or the FF UFX PSU.
4 Pin Molex:
Black to Red 5.5 VDC
Black to Yellow 15.7 VDC
Black to Blue -16.40 VDC
2 Pin Molex:
White to Red 49.24 VDC
I have disconnected the ribbons cables to the Word Clock PCB, the I/O AD-DA PCB as well as the Molex connector between the FPGA DRAM PCB and the I/O AD-DA PCB. There is no change in any DC Voltages or Display symptoms with the other PCB's disconnected.
There is a Su'SCON super capacitor labeled C660 on the silk screen of the FPGA/DRAM PCB I believe to be Part #MCM5R5334ZG18()R that is probably used to maintain non-volatile memory for DRAM or FLASH. When the unit is powered up I read 1.26VDC across C660 and when powered off overnight I read .7VDC.
So here are my questions.
How do I back-rev the F/W on the UFX? Is there a default NON-VOL Flash image that I can reset the unit to, and then try a different F/W image upgrade? If so, how do I do the F/W back rev?
Do the DC Voltages from both PSUs sound in range and proper?
Does the DC voltage across C660 seem proper when the unit is powered on and powered off to maintain memory?
Is the FPGA/DRAM PCB available as a replacement and if so, how much?
Please Advise
Robert Economaki
UPDATE 2019-05-24
After performing the above procedures, I decided to USB attach the FF UFX back up to the computer.
After a reboot, I noticed that Device Manager reported a funky icon for the USB FF UFX device but the LCD display was still all white and the State LEDs all lit.
I reset the FF UFX to factory defaults and the FF UFX LCD display started to work normally but I still had the strange Device Manager Icon.
I power cycled the FF UFX. The LCD was fine but I still had the funky Device Manager Icon.
I reloaded the most current driver and Device Manager Icon was now correct and the FF UFX seems to be working fine and stable for 12 hours.
I am curious how long the unit will stay stable. I will post any changes if things go down hill from here.