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An HP-32E repaired. Calculator 1

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This calculator was not used for a long time with its batteries inside. It was non functional when I received it and the batteries showed serious leakage. The complete battery compartment was filled with white potassium hydroxide (KOH). After removing the batteries I cleaned it thoroughly.

To observe the internal damage caused by the leaking batteries the calculator had to be opened.

To open a Spice model calculator isn't that easy. First two little screws near the battery compartment must be removed. To open this calculator an excess of power is needed. See the first document linked on bottom of this page. Later an other, more gentle way of opening this series of calculators were proposed by Geoff Quickfall and Karl Schneider. See links on the bottom of this page.

HP32E_1 HP32E_2

The pictures above show the internal of this HP 32E calculator. The printed circuit board and the keyboard are held together by metal strips. The display is a separated module, clipped on the main circuit board.

A lot of damage was observed on the LED display module.

HP32E_3HP32E_4

The white substance from the batteries (potassium hydroxide) collected under the plastic lenses and damaged the two outer LED display chips. After removing the lenses the pollution could be observed even better.

HP32E_5 HP32E_6

The digits are separate chips glued on a substrate. Connections are made by thin golden wires (bond wires) connecting the segments with the printed wiring on the substrate. On the left picture the most left 'digit' is shown. This digit contains only the minus sign. This complete chip is delaminated from its substrate and is dangling on its bonding wires. The blue substance is cupper hydroxide, cupper wiring harmed by the leaking batteries. The right hand picture shows the rightmost digit with the white substance around it.

I will try to clean this display later. This must be done very carefully, without damaging the bonding wires. Meanwhile I will look for a second one as a display donor. I found one on Ebay but this calculator could be fixed rather easily. See calculator2.

I bought a single Display on Ebay and used it to fix this calculator. I opened the calculator again and cleaned the battery contact print. The foil between the battery contacts and the power supply print was replaced by a piece of ribbon cable. See photo below.

HP32E repair

The calculator is fully functional again.

 

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Spice repair related links:

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