41CV auto off question


My 41CV is now turning off automatically in 20 seconds
since I installed new batteries. Can it be set back to
the original 10 minute turn-off?

Edited: 5 May 2007, 5:46 p.m.


Hi Scott,

This has nothing to do with the new batteries set nor it's re-settable to the standard 10 min. timeout by any keystroke sequence.

I will assume yours is a Fullnut (square display corners). In these models time constant for Auto-off feature is determined by one mask programmable oscilator inside the display unit.

That oscilator (OC1) signal requires an external capacitor (C2) which is placed (also soldered) in the main board.

The path from the OC1 line in the display to C2 in the main board comes thru display pin-4 (soldered to the keyboard PCB) and then thru "zebra" strip into pin-1 of the main board.

Assuming solder joints are is good shape, and capacitor is not damaged (I see no reasons to suppose the contrary) chances are that your calc is suffering a weak screw-post or damaged post case.

More likely in the bottom left screw. To comfirm the last, please check pressing firmly the keyboard frame on the "cross" of "x" "/" "1" & "0" keys as well as on "2" "3" "." "R/S" keys while calc is ON. If your cal doesn't turn OFF in 30 sec. The reason of the malfunction is the referred "weakness".

There are several ways to fix that problem, please see "Articles Forum" Article nr. 2 for details.

Hope this helps.

Diego Díaz.


Thanks for the explaination --
You were right, tightening the rear screws solved the problem.
I appreciate the help. I use it almost daily and this was
a big help! Scott

Edited: 7 May 2007, 2:45 p.m.


Thanks for the feedback Scott, It's nice to be useful... and help keeping a 41 in working order. ;-)


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