HP 25 faulty

[sylvain]

Hi list,
My HP 25 has a display problem which arrived sudenly, yesterday no problem today it displays only the last zero on the right side of the screen, and that zero is much more brighter than usual. When i key any of the keys no response at all. Is that serious and is there any way to fix it?

[David Smith]

The most likely problem is a bad ACT chip. The only source for a replacement chip is another machine. You can use the chip from a HP21/25/25C/29C/67/97. It is the big 22 pin chip with the rows spaced 0.4 inches.

[Victor Koechli]

I might add that in some cases the problem could go away if the machine is left turned on for some time. Some of them have to get warm in order to work properly. Could take anywhere from several minutes to an hour.

Cheers, Victor

[David Smith]

But with loss of display scan, you can easily fry the LED digit that is lit.