The Museum of HP Calculators

HP Forum Archive 03

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Message #1 Posted by gshaw on 26 May 2000, 3:46 p.m.

does anyone know how to fix the display turning off within 2 seconds of my last entry. i have check the function that sets the calculator to turn off after no use, but that seems to be okay. the batteries are new also.

any suggestions?

Re: HP41CV
Message #2 Posted by rupert9000 on 27 May 2000, 6:33 p.m.,
in response to message #1 by gshaw

As long as I know the HP41 turns off after ten minutes of inactivity, not just two seconds. Have you set the flag 44 with the ON function (XEQ "ON", not the [ON} key) ?

Re: HP41CV
Message #3 Posted by Steve on 29 May 2000, 8:06 a.m.,
in response to message #2 by rupert9000

There is a fault that produces this behaviour.

I'm sorry but I don't recall what it is. As I understand it (and I may be wrong) but the timer for the 10 minute power off is located on the display board.

Maybe you have a fault on this?

The problem may be a bad connection in the calculator somewhere. If you're feeling brave you could open it up and try to find and fix it.

The points of weakness seem to be the connections between the upper and lower board, and the connections to the display board.

Best of luck

HP41CV turning off
Message #4 Posted by Andrés C. Rodríguez on 29 May 2000, 9:58 a.m.,
in response to message #3 by Steve

This is just to confirm that the automatic off function is controlled by the display, so it is a possible suspect.

Keep in mind that the HP 41 has three operating states:

- sleep (off but keeping memory contents),

- standby (display is showing the last result),

- running (a peripheral is operating, a program is running or a key function is being pressed or calculating)

When in standby state, the display is the "only" working part of the calculator. ("only" is a relative word in this context...)

Other (less probable) suspects are the power supply chip and the internal connections between boards.

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