HP48SX annunciator line problem

[isanchez]

Dear friends,

I have a working HP48SX, very nice. The external state is mint.

The only issue detected is that the annunciator line (the upper display area, not the dot matrix, but the six predefined symbols: Arrow-left, arrow-right, hourglass, alarm-clock, etc.) does not work. I can see all of them very dim, even if the calculator is off, but no response when activated...I enclose a photo with the calculator turned off.
Maybe you have experience in what could be the problem.
Could be a defective display?or the zebra connector? All keys do work perfect.

If you find it is the display: are the displays from the 48's family compatible? i.e. can I use one from a 48G+ as spare part for the 48SX?

Thanks and kind regards

Ignacio