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Grundy Newbrain – Battery Expansion Unit Repair

Grundy Newbrain - Riparazione Battery Expansion Unit

This is the Battery Pack for the Newbrain, very comfortable and very light :-D useful for taking the computer to the beach during the summer holidays.

Obviously the Battery Expansion Unit after many years of inactivity has presented some problems of the 20 x 1.2V 600mA NiCd batteries.

The batteries besides being completely exhausted i had leaked acid. (see photo)

Fortunately, there are no major damages with the leakage of acid and it was enough to clean well, unsolder the 20 batteries and replace them with new ones of 1000mA.

Last update: I noticed a malfunction of the Battery Expansion Unit, when i set the switch to OFF the “discharge” LED remained on.

Looking at the schematic, the switch suspend the charge and the use of batteries, the problem was caused by a pcb pad (see photo) that at first sight seemed to be connected together with another, immediately close, but in truth it was not so, it was enough isolate the connection and now everything works correctly.

Gallery:

  1. Philip Lord
    August 8th, 2021 at 21:12 | #1

    Hi, Great job. Can I ask where you got the batteries (with tabs) from? Cheers

  2. Philip Lord
    August 10th, 2021 at 02:31 | #2

    Did you ever consider soldering in some battery trays? I need to do the same as you and just wondering what the most future proof option is:

    https://www.aliexpress.com/item/4001156346699.html?spm=a2g0o.productlist.0.0.13ce55598PvyN3&algo_pvid=f3bb0ec7-d616-4135-b2d5-ca8d8d447d65&algo_exp_id=f3bb0ec7-d616-4135-b2d5-ca8d8d447d65-31

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