My Phaser 850 keeps returning an error message saying "Replace Upper Media Tray," but the upper media tray is correctly inserted & loaded with paper. Printer won't even print from the manual load tray. What can I do?

This can also be caused when the upper cassette tray (for small paper stock / photo paper) becomes detached from the lower tray. There is a gear attached to the lower paper tray which handles movement of the upper paper tray. Make sure that moving this gear causes the upper paper tray to move. If it doesn't, then you need to snap the upper paper try on a little better.

This can also be caused when the upper cassette tray (for small paper stock / photo paper) becomes detached from the lower tray. There is a gear attached to the lower paper tray which handles movement of the upper paper tray. Make sure that moving this gear causes the upper paper tray to move. If it doesn't, then you need to snap the upper paper try on a little better.

I had this same problem and tried everything (I thought) to fix it. Then I saw the solution at:
http://www.retrevo.com/c/sohohelp/blogs/show/6633/I-just-had-my-espon-artisan-800-replaced-and-the-refurb-keeps-saying-that-the-paper-cassette-is-not-seated-correctly#replyForm

Basically there is a plastic pin that tends to break off and stays in the area where the cassette is loaded. It takes up just enough space to keep the cassette from being pushed in all the way. The solution is to turn the printer off, unplug it, then lift up the printer so the broken pin falls out. Once it comes out, the printer will work fine again.

Please check your printer driver to see if the default tray is tray 2 or other than the manual feed tray and take the paper out of the manual tray.

11,001.47: Upper 525-sheet feeder broken serial link detected.

1. Ensure ground integrity for the printer.
2. Did this resolve the error?
Complete. Go to Step 2.
2 1. Inspect and reseat all connectors.
2. Inspect the gray cable between the I/O board
and the electronics module.
3. Ensure the cables are properly dressed in
the wiring raceway as detailed in the wiring
diagram section of this manual.
4. Did this correct the problem?
Complete. Go to Step 3.
3 1. Reset NVRAM and retest.
2. Did this resolve the problem?
Complete. Go to Step 4.
■ 11, 001.47 and 11,017.45 Replace tray lift motor or the
electronics module.
■ 11,002.48 and 11, 016.44 Replace lower tray assembly

My experience (with the R280) MAY have some relevance.It turns out that, should you turn the printer power on WHILE the output tray is in the upper (DVD/CD) position, you get an undocumented pattern of error lights, error message, and no ability to print. The cure (for the R280) is: just move the tray to the lower position and leave it there long enough for the printer to complete its power-up cycle and initialization, after which the green POWER light will be solidly on. Then you can shift the tray to the upper position for DVDs, or go ahead and print on paper where it is. Epson "technical" "support" people all deny that this is the way it works, and they want me to return the printer for replacement. I have confirmed the behavior on TWO different R280s. They also deny that their CD-Label software scatters "CDLabel.alb" files whenever you load a photograph as background, but that's another issue, and fortunately non-fatal.

Tektronix printer paper trays, I seem to recall that there's a plastic key that fits on the right side of the paper tray. It's a little plastic piece that just clips in on the right side of the paper tray. Sounds like it's missing

Have you loaded both trays? The bottom tray and the upper tray ? The one that folds into the machine. Something may be trying to run from tray 1. Upper tray

Once remove both the trays and insert them again and if the problem persists, power cycle and semi-full reset the all-in-one.

Here ya go...

Tray 1: (standard) 16 lb. Bond – 80 lb. Cover (60 – 220 gsm), coated, Phaser High Resolution Photo Paper, labels, envelopes, business cards, Phaser Professional Solid Ink Transparencies, Phaser Weatherproof Paper, Phaser Postcards, Phaser Trifold Brochures. Media sizes: A/Letter, Legal, Executive, Statement, US Folio, A4, A5, A6, B5 JIS, B5 ISO, 3 5 in. Index Cards, custom sizes; Envelopes: #10 Commercial, DL, C5, #5 , #6 , Monarch, Booklet, Lee (A7), Choukei 3 Gou, Choukei 4 Gou, custom.
Tray 2: 525-sheet tray (standard) 16 lb. Bond – 28 lb. Cover (60 –122 gsm), coated, Phaser High Resolution Photo Paper, labels, envelopes, Phaser Professional Solid Ink Transparencies, Phaser Weatherproof Paper, Phaser Postcards,Phaser Trifold Brochures. Media sizes: A/Letter, Legal, Executive, Statement, US Folio, A4, B5 JIS, B5 ISO; Envelopes: #10 Commercial, DL, and C5.
Tray 3: 525-sheet Feeder (standard on DX) Same media weights and sizes as Tray 2.
Tray 4: 525-sheet Feeder (optional) Same media weights and sizes as Tray 2.