What made this Uniden BC760XLT fail?

Uniden BC760XLT scanner radio, serial # 05002596, code ODIO.

No options have ever been installed.

This unit worked perfectly at an estate sale on July 23, 2005.

I shut it off, packed it in its original box, and bought it.

Later that day, I unpacked it, connected power

(factory-original wall wart), and switched it on.

To my great disappointment, the display lit up, but was absolutely blank.

There were no apparent results from pressing any button.

The only controls that work are volume and squelch:

The unit seems to be capable of receiving signals

(it does receive band noise) and can be quieted,

but it won't change frequency (not that one can tell

without visible characters in the display).

Checked lithium backup cell: Measured 3.3V in circuit.

8V regulator seems OK:

Measured 7.8V across functioning display lamp.

A technician at Universal Radio suggested resetting the unit

by holding 2, 9, and MAN while switching power on.

I tried that; it made no difference whatsoever.

All evidence points to the conclusion that the firmware has been lost,

but since there are other possibilities, one must keep trying.

That's why this question is being posted.

I don't have a service manual. Looking for one has proved futile.

The company doesn't service any model over a certain age,

and this one is far past that point, so forget that idea.

SO: What failed, and what can be done about it?

>> Based on my experience and the remarks of others,

I believe I've figured out the reason for the name Uniden:

If it doesn't work, "U NEED EN" new one.