A costly calculator repair

This MS-7LA calculator came in for recycling last year. It did not power on.

Casio MS-7LA
It is the holidays at present so I thought I would do some holiday hobby work (repairing things is one of my hobbies).

I undid the three screws on the back of the calculator and the back cover come off fairly easily. The leaky battery was easy to spot. I cleaned the circuit board and put in a new battery. Still no go!  On closer inspection the circuit board pad looked a bit tarnished. I then spotted the completely corroded PCB track that would have been where the interface between the anode and cathode of the leaky battery was positioned.

I removed the battery clip, cleaned the anode terminal, and added a wire link (the blue wire in the photo below) to fix the corroded track.

Inside view of the Casio MS-7LA With the battery back in the calculator was back in operation.

That all took me about 20 minutes.  At our current labour rates that would have cost a customer $26 for the labour alone and at our current minimum repair fee cost it would have been $35.  The battery costs $3.25 or $5.00 for one of good quality.

You can buy a roughly equivalent calculator of a well known brand for less than $4.00.  The current Casio equivalent sells for $20 but I can probably only get $5 for the one that I repaired.

About Alan Liefting

Alan Liefting is the founder, a shareholder, and the Managing Director of Ecotech Services. The views expressed here are his own and do not necessarily represent those of Ecotech Services Ltd.
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