HP15C displays gibberish. Is it broken?

[Chr Yoko]

i know thar vendor, i bought an HP IR printer from him with a slight price decrease. he is honest and nice guy, but as he has over 500 items on sales, and maybe only one calculator, i guess he can't help you much as he may even don't know how does it works.

also that 15c looks pretty biten on the rear, no visible battery door and may have been open?
i would pass on? as keyboard may also be damaged somehow

and buy a brand new DM15L instead as i did few weeks ago ? with no regrets and leave those old used models to collectors