2145cn cannot see Tray 2

After an up-and-down power outage a couple of days ago, our Dell 2145cn printer cannot see Tray 2, where we normally keep our pre-printed legal-size card stock. The printer can sense Tray1, Manual Feed, and MFP tray, but it no longer senses Tray 2. This is true for both the on-board menu (on the printer screen itself, under Paper Settings, where Tray2 no longer appears) and via the printer's HMTL/web interface--so I assume this is either an internal electronic problem or a problem with the physical/electrical interface between the tray and the printer.

Tray 2 is the bottom add-on tray that sits below the printer. It is connected to the printer by what looks like a DIN or PS2 cable and also has small spring-loaded metal pins on the top that presumably press against metal plates on the bottom of the main printer when it is in place to provide some sort of electrical connectivity function.

I have rebooted the printer via the power button multiple times, disconnected it from power and let it sit multiple times, removed/re-inserted Tray2, disconnected/reconnected the Tray2 wiring harness, lifted the printer off Tray2 and carefully set it down again in position--all to no avail. For now, we are using the manual feed tray for our legal-size printing, but that means leaving the tray sticking out in this fairly tight printer space (it is in a very small flower shop) where it is sure to be knocked off eventually.

This is way outside warranty, and I cannot even be sure the problem is with the tray itself. It could be in the electronics of the main printer unit, so I don't want to just run out and try to find a replacement tray.

Any ideas?