How to repair HP calculator with two cell ni-cd battery pack* (see disclaimer below).
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Some small HP LED calculators (as the HP-32e or HP-33e models) relies on two elements ni-cd battery pack, usually dead due to age. Battery act as current stabilizer so it's necessary also when you connect the power adapter. Test your calculator using any 3V external source: external battery or stabilized 3 Volt power adapter. Use crocodile cables to connect (+, positive) to the 'internal' battery spring, (-, negative) to the 'external' spring. With this test you could exclude internal damages due to battery leckage. |
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The repair idea is to make the calculator able to host any standard AA (ni-cd or alcaline) cell. Start cleaning the contacts. Write + sign close to the 'internal' (left in the photo) battery spring. |
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Built the missing series connection between the cell on the back. Use aluminium foil glued with double side adesive film. |
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Now you should be able to place two standard AA cell. Respect carefully the polarity. Remember: don't use the adapter/charger if standard or alcaline battery are mounted (battery could leak or explode). If you are using ni-cd (or ni-mh) cell, connect the charger and recharge your battery overnight. The charging time proportionally increase if your battery have more than the 450/500 mA original capacity. |
(*) Disclaimer: We offer this repair experience as it is, without any warranty about contents or results (results depends by your personal ability, electronic knowledge and also lucky). Use this information at your risk: we are not responsable for injury or damages eventually caused.
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