07-24-2006, 02:02 AM
I have a HP75C which is malfunctioning. With battery removed for some hours, I press ATTN and then insert a fully charged battery. After this I press ATTN once again, the Time Setting Line appears on the display. I can also set the time and go to EDIT mode. After a while the calculator either hangs up or turns-off. Before it hangs I can run a program by reading from the card reader. Trying to reset according to manual does not help. Does anyone has a clue how to solve this problem? Does anyone have a copy of the service manual? I would very much appreciate. Thanks. Prabhu