41C is ON, display is OFF, a key pressed display is ON --Repair Help

[TallKey]

Replaced the driver board. Never want to do the it again, but probably will.

My problem is replacing the display clips. The are removed easily enough. Installation, for me, harrowing.

The front and back glass
surfaces of the LCD module each have a
plastic layer that is easily damaged,
and the contact fingers on the display
driver PCA are easily damaged.

The display driver board is pretty darn flimsy, Mr Manual.

Sadly the bad driver board looks just like the good board. Anyone know what causes driver boards to fail?

Thanks all who helped ID the problem and having the HP Service Manual at hand is a big help.

The donor 41C has a few display segment problems. Moved the known bad display driver to the donor 41C. Driver behavior, no change in the donor 41C.