I got a hp-38c recently. However, it does not work. The display turned on, but when I press the keys, it registered only 4 key presses, the fifth key press would not displayed. Moreover, it displayed funny digits, sometimes 00000 and sometimes with "-" and decimal point. I have opened it up (including the display screen, metal clips, etc) and clean all components, but it still does not work. Is it because some of the chips (there are three of them) are not functioning ? (connecting cable/battery contacts are in good condition.) Can anyone help ?

Be sure to have a battery when testing it with the AC cable. My 38E was doing strange thing without a battery in it and the AC cable connected.Or test it with 2 regular AA battery.

Thanks for your message. Yes, I tested it with batteries and not AC cables. But it is not working.

I think that the most likely (sad) reason is that someone before you "tested" the machine with the AC supply but with no batteries connected. Continuous memory models tend to die an early death when this happens.

If you have access to a working HP-38C, you might try swapping chips and see what happens; you may be able to identify a faulty chip.

Viktor