HP-25 turns itself off

[Des McPherson]

Ok, here's a strange one. I was playing around with my HP-25 the other day making sure all the buttons work. I went through each number and pressed it over and over until it filled the display. When I got to the number 7, I pressed it 5 times and the calculator turned off. It turned back on again after sliding the switch to off and then on. Here's some of the patterns that turn the unit off.

77777
177777
2277777
3337773377

You get the idea. Any help would be appreciated.

[Geoff Quickfall]

I would like to say that entering five '7's in a sequence or over the 10s display is the "secret off code" for the HP 25 but I can't!

Sounds like a memory and display problem. The x register is a memory. Did any of the other keys when entered five times in a row or any sequence of five presses over the 10s display cause a similar fault. Also try:

388885 ENTER 5 /

this should develop 77777,

Does it turn off when it generates the 5 sevens.

Cheers, Geoff