Alphasmart Neo 2 Battery Support Positive Terminal

This thing builds upon the excellent work from electronicsluckydip for a replacement negative battery terminal (the one with the spring) on the Alphasmart Neo2. This is a remix that adds a second object to support the positive terminal.

When batteries corrode, the plastic that holds the battery contacts can weaken and break under the pressure of expanding corrosion. This plastic is already rather thin on the Neo2 which is otherwise an extremely durable case. However, given the intentionally snug fit, three AA batteries push outwards against the terminals on both sides, and the thin plastic “slots” snap, leaving the terminals unsupported and falling back inside the shell. The negative side with the spring might break first, since the owner pushes batteries against this terminal to compress the spring. However, I have restored several examples of the Neo 2 where the positive terminal is broken too.

This is a snug fit—maybe even a little tighter than electronicsluckydip‘s original. You do have to grind out the existing plastic to clear the way for the replacement. Like the original, this butts up against a plastic “wall” further inside and provides a more solid backstop. The difference here is that the space behind the positive terminal is used to store the connector for the optional rechargeable battery pack. As such, I needed to make this side a bit more hollow, and notch it appropriately for the wires to enter this area.

Print Settings

Printer:

Prusa Mini

Rafts:

Supports:

Resolution:

Infill:

Filament: Overture PETG black

Notes:

Post-Printing =============

You need to open the Neo2 to do this work.

The fit is snug. Grind out the old bracket so the slot is smooth, then position the new bracket in its place. Make sure the angled side is placed down against the shell (what will look like the inside bottom as you look down into the battery compartment). You want to line up the far right side against the wall. Imagine pushing batteries up against this from where they sit. The bracket is designed to transfer this pressure all the way to the backstop inside wall.

Holding it in position a couple drops of superglue will go a LONG WAY toward securing this against the shell. It’s not going to fall out if you don’t glue it, but a little CA glue will wick up under the bracket and hold it in place very securely. There will be an air gap above, so this keeps it from rattling up and down since you basically have the Neo belly-up while you are doing this work.

This goes for BOTH sides—both replacement battery terminal holders will work better if secured with glue. This remix includes the original STL file plus mine.

It can help to test fit the metal terminal before you start. It slides in nicely, but it should go all the way down in the corner closet to the front because the shell has an incline. It may be easier to adjust the slot with a knife if needed BEFORE you glue it into position.

It maybe goes without saying, but this whole operation often involves cleaning an alkaline mess. Do that first, or after you grind out the plastic in your way. Use a toothbrush with vinegar to neutralize any battery goo and corrosive bits, then clean with a mild soapy water and rise. Magic Eraser can help scrub stubborn white film. Get it clean, dry and then proceed.

How I Designed This

This was designed in TinkerCAD using the original, reflecting it to the opposite side, expanding the top dimension while preserving the angle, and reducing the “block” sections to preserve as much of the hollowed area for storing the rechargeable connector wire.

Category: Computer