HP41-CV Troubleshooting

[hoit]

When putting in new batteries / turning on my HP-41CV I'm either getting

1) a high pitched squeal
2) a set of characters on the screen

https://imgur.com/V363v29

I have tried a hard reset without success. The batteries are new and the battery terminals are in good condition without corrosion.

I have also tried the options here
https://www.hpmuseum.org/cgi-sys/cgiwrap...i?read=149

What can I try next.

Many Thanks