This post is for the forum in general. I recently purchased an HP-80 that had a few problems. It was missing a battery, the zero and five keys were not working properly and the on/off switch worked intermittently. Thanks to this forum and the archives, I was able to purchase a battery that works flawlessly and disassemble and repair the keys and on/off switch. I also followed the recommendations for cleaning the calculator before putting it back together. The results... I have a like-new HP-80 that has all of the wonderful characteristics that make the "classics" well - classic. All of this was made possible by the knowledge and experience captured by this website. Keep up the great posts and articles and thanks so much for the good information.
Best regards,
Mike