HP-85 Screen issue

[KLund1]

Hello,
First time to this forum. Not sure if I am in the right place. If not, could someone kindly direct me to the correct forum.
I have just added a good condition HP-85 to my vintage computer collection.
The trouble is the first line of text on the screen is vertically compressed to about 1/4 normal character height. The two easily accessible controls have no effect on this
Any suggestions how to correct this?
Many thanks
KL