Dead 41C?

[Geoff Quickfall]

Modify that old post with the following:

DO NOT do the drop method.
DO NOT do the twist method.

DO check that the screws are tight, but, DO NOT over tighten. Loosen them then tighten until they JUST sinch up.

So do the following before opening up testing at each step:

-Check screws for tightness. DO NOT over tighten. Are any stripped? Are any loose and will not tighten? Do the two shells look or feel loose, Check for gap between the two shells and the spacer.
-Two finger salute: ON and CLEAR memory reset.
-Remove batteries and short the far left to the far right battery contacts.
-Remove batteries and replace in opposite polarity. Place in calculator, turn on and count to five then turn off. Remove pack, correct polarity. Reinstall and check.
-Remove batteries and leave a few days.

DO NOT THROW OUT!

Next will require surgery:

-Separate the shells (four screws under the foot pads).
-inspect the screw posts, any cracks, are they broken at the base?
-Foot pads are anti static impregnated with conductive material.
-Any visible corrosion?
-There are two contact groupings on the full nut keyboard. Clean the keyboard PCA contact points with lint free cloth and anhydrous alcohol (or isopropanol 99%). Do not substitute with a harsher solvent.
-Clean the battery/module contact points in the same manner.
-Inspect the battery/module block. There is a foam strip which pushes the contact on the battery/module block against the keyboard PCA. Is it flattened? Pinch the sides of it to get it to push the contact point higher.
-Clean the contact block (wire wrap or elastomer assembly).

Do all the above then reassemble.

There is a capacitor in the calc down by the old battery ball contacts on the keyboard PCA. It is electrolytic and MAY need replacing. Last resort would be to replace it as it may have dried up internally.

Let us know how it goes!

Geoff


Don!

Cell phone is for work and on days off I never carry it as I don't want to work! So I did not get your message until going to London Saturday. The problem has been solved via the committee.

Cheers, Geoff.

P.S. Quanta lumes suggestion is excellent, before the surgery follow his press suggestion. The intent is to see if the compression force at all four corners of the calc will revive it. If the screws are tight and this does work it indicates the contact mechanism of the battery/module block or the wire wrap or elastomer assembly at the lower contact point are not fully functional.