[PB903] stylus (?) stopped working

[geos]

hello,

I have older PB 903 model and used original stylus pen to make notes. Today I noticed the reader is not responding to stylus pen. It stopped working, just like that. The reader "responds" with green diode blink when I touch the screen with a pen, but it doesn't have any consequences in any action on the screen.

I'm in the process of finding out a new working pen to see if reader works with it but maybe someone can tell from his/her experience: does it look like something serious and unrepairable? Or maybe just common issue with stylus pen only? Or maybe besides buying new pen there is another method to diagnose the issue further?

thank you,
geos