Screaming HP41CX

[Charles]

I have an HP41CX i excellent condition which worked perfectly. Now, when i out batteries in it, it just emits a high pitched whine and won't switch off. I've tried all the resets on this site without any success. Does anyone have any ideas?

[John Limpert]

I had an HP-41C that died in a similar manner. I tried resetting it and installing new batteries, nothing helped. I hope you have better luck.

[Raymond Del Tondo]

Hi,

just initiate a normal BEEP.

That will reset the tone register,

and the noise will vanish;-)

Regarding the reset, try the ENTER+ON key combination,

and unplug all modules before.

HTH

Raymond

[Charles]

Hello,

I tried pressing BEEP but it didn't make any difference. Have I pressed the right keys ? I also have a bit more information. When I put batteries in, it is silent. If I then switch it on, it makes a whining noise. If I press ENTER and ON, the noise gets louder. If I them press ON and ENTER a few times it gets softer again but I can't switch it off and have to take the batteries out. Any ideas ?

[David Smith]

Take it apart and clean all the circuit boards and connectors with 91%+ isopropyl alcohol. Keep the alcohol off the display window as it will leave white marks (which can be polished off).