Can I use the hp45 display for HP55?

[dramsey]

Yes, the LED displays (three 5-digit modules) are identical in all of the first generation machines (35, 45, 55, 65,67, 70, 80). I've replaced them myself.

You do need reasonable soldering skills. But heck, if I can do it...

One warning, although there's not much you can do about it: the brightness of the digits in each 5-digit module are matched, and HP matched the brightness of the modules used in each individual machine. It's possible-- likely, even-- that you won't get a perfect brightness match with the replacement module.

Also, before reassembling the calculator, take a little time to bend the legs on the newly installed module so that it lines up as well as you can make it with the existing modules.