I checked my two KXs and the black needle does go above 1000 when the exposure meter is turned off.
When you press the battery check button the black needle should go to 125 or lower, indicating there is enough capacity. Have you tried new batteries?
You may want to get the metering system checked and adjusted. Eric is the CLA expert, link below:
http://pentaxs.com/index.html
Here is a link to a KX manual:
http://www.pentax.ca/pdf/o_manuals/om_KX_e.pdf
Enjoy your new camera, it's a great classic K series body!
Phil.