HP Color LaserJet MFP M277dw has blank white touch screen, but printing is OK

[KF54]

Was printing an envelope using Microsoft Word.   Printer's touch screen prompts you to manually feed the envelope and then press OK.  When I pressed OK on the touch screen, it went blank (white).  The envelope printed OK, but the screen is still white.  

Tried powering off/on, no change, screen is still blank white. 

Read everything I could find in HP forums about this issue, and have tried the following fixes:

Tried unplugging power cord from printer while printer power was on, then unplugging from wall, then holding power button on for 30 seconds, plugging back in and powering on--no change.   Prior to trying this fix, printer had always been plugged into a high-quality surge protector/battery backup device.  It is currently plugged directly into a wall outlet.

Printed configuration report and verified firmware is at latest datecode of 20180205. 

Downloaded and ran HP Print and Scan Doctor 5.2 twice; both times it said "some issues were found and fixed" and "recommended updates installed"  but showed everything is OK and all green checkmarks.  

Ran HP Device Toolbox; everything looks OK.

No recent software, hardware, or driver changes on any devices connected to the network.  Have had a few print jobs "hang" the past few days, but nothing is in the print queue and both PC's on network have been rebooted.

Printer is connected to internet via via wireless network connection.

Have NOT tried the factory reset where you press and hold the lower right-hand quadrant of touch screen, since it shows you then need to USE the touch screen to see the menus to do things like reset language to English, etc.  

Printing and scanning from the network works just fine.  Cannot use as a COPIER since the touch screen doesn't display anything and can't see prompts for things like loading paper via manual feed or "paper tray empty" messages.

The printer is 3 years old and the extended warranty expired 4 weeks ago.   Except for this touch screen problem, printer Is still like new and only has 3,177 impressions on the print engine.    Please help--thank you!

[SHThompson]

It is unlikely that a reset will restore the display to normal operation.

As a technician my first step would be to reseat any cabling between the display and the rest of the printer, I would refer to be repair manual for that model to figure out where that cabling was. Basically I'd look at the steps to remove and replace the display which would show me where all the cables that connect to the display where located.

I suspect the display has failed and will need to be replaced.

HP does not put the repair manual online however you can usually find a copy if you know the name you're looking for.

[KF54]

Thank you for your post, Professor Thompson.   I appreciate your post, but it does not provide a solution.

I also suspect that the touch screen display has failed.  I hope that a simple loose connection is the problem, but connections rarely go bad when the equipment hasn't been moved for months or years--and we haven't had any earthquakes lately.  

Before reading your post, I had already found instructions on how to remove/reinstall the display (but

a special tool might be needed to open the plastic cases to access the display and cabling):

[edit]

The comments on the iFixit post also mention that replacement display parts are difficult (or impossible) to find.  HP doesn't appear to sell this part. 

Tomorrow, I will see if it is possible to access the display and its cabling without damaging the plastic cases.  If so, I will reseat the cabling between the display and the motherboard.  I've reseated many computer cables before...sometimes it works!

Any suggestions on where to purchase a replacement touch screen display or thoughts on why HP doesn't sell this part?  How can I repair this printer if I can't purchase the replacement part that has failed??   There are NO authorized HP repair facilities within 50 miles of my location.

Thanks again!