LaserJet Pro MFP M127 jammed document feeder no paper

[garys25]

The document feeder just stopped working, and I'd like help to return it to operation.

When I attempt to copy with an original document in the feeder, the front panel displays "document loaded" then immediately quits with "Document feeder jam. Clear and reload. OK". The feeder doesn't attempt to pull in the original. Pressing OK results in beeps but no other response from the printer. Only power cycling returns the printer and front panel to operation.

I've tried the usual remedies from forum postings for similar issues but no resolution: checked for actual paper jam (there wasn't any), cleaned the rollers, vacuumed out any paper dust, reset the printer to factory defaults, power off 30-60 seconds.

I checked the firmware revision in the printer but it seems old (20150818). I don't see anyway to update it from the front panel or the website. Other forum postings refer to the tech sending a private message to the poster with printer specific procedure for updating and resetting. Perhaps, I can try a similar reset procedure for my M127fw. 

The printer, other than the document feeder, works fine: Manual copy, scanning, printing.

[garys25]

Update: something I saw in another post said pressing the OK button very quickly many times while the input feed tray and document feeder were open sometimes restored the touch panel menu and fixed the ADF problem. I tried that and got the ADF to work once. But once the original document fed through the ADF and deposited in the output tray, the paper jam error appeared. No copy was generated. This time, no amount of OK button mashing restored the touchscreen so I had to power cycle the printer.

The fact this worked once indicates that at least the document feeder mechanics still works.