Battery powered, word-processing keyboard manufactured by NEO Direct, Inc.

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Strange soldering inside an Alphasmart Neo?

Here's a strange one…

I recently bought a used Alphasmart Neo that can be powered up via the AC jack or with a rechargeable battery, but not from the AA battery chamber. When I opened up the unit to see if I could figure out what was wrong, I saw that someone had soldered a copper colored mesh wire about 1/8 inch wide and maybe half a millimeter thick around the edges of the motherboard. This doesn't look like factory work and the other Neo I have does not have any wire mesh or soldering like this.

The mesh is soldered to a point on the motherboard that connects to the black wire that runs to the rechargeable battery. On the other end of the motherboard, the mesh is soldered to a point that connects to the black wire running to the battery casing. Other parts of the mesh are soldered to the metal casing around the USB ports and to a bit of metal on the side of the inner plastic housing of the AC jack and to a number of other points of metal along the edges of the motherboard. A small extra bit of mesh wire has been extended to connect to a bit of metal on the interior edge of the display.

There's also a small bit of red wire that's been soldered to connect a piece of metal at the base of the interior casing of the AC jack to a point on the motherboard.

Finally, whoever did this also ran black electrical tape underneath or alongside the mesh (perhaps to protect parts of the motherboard during the soldering?).

Does anyone have any idea what purpose this mesh wire and soldering could serve? It seems like a big safety hazard to me, since it appears to be connected to the electrical system in at least two places. But the system does work -- it just can't be powered by the AA batteries. (Although I'm not going to plug it into the wall again now that I've opened it up and seen what's inside!)

If anyone can shed any light on what might be going on here, I'd appreciate it!

UPDATE: I called the folks at Neo Direct, who told me that there's no reason they can think of for there being this mesh wire soldered around the motherboard. Finally got a soldering iron and removed it. Also removed a bit of red wire that had been added to connect the inside of the AC plug to a point on the motherboard. Now the AC no longer works. And the AA batteries still don't work. But the rechargeable battery and the USB connection still work, and the battery can recharge through the USB connection, so the machine is functional.

My guess is that the AA battery chamber and the AC conked out and someone did all of this soldering to try to get them to work again.

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the mesh sounds like ground strap, especially considering the points it is soldered to.

I looked up the product website, and see they offer two models - with and without rechargeable battery pack. The pic of the unit with the battery pack appears to show the pack soldered into place - a red wire is clearly visible:

http://www.neo-direct.com/NEO/productdet...

Perhaps this explains the difference you are seeing? Or it could be a refurbishment modification...

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Thanks for the quick reply! I'd thought this might be related to grounding, but I don't know enough about electricity to understand why that would be necessary for this kind of machine. Any ideas about that? And about the safety of using the machine with this kind of soldering?

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Regarding the battery pack... both of my Neos are able to use a rechargeable battery pack, but the pack isn't soldered in place -- it fits into the AA battery chamber but doesn't use the AA connectors. Instead, it has red and black wires that terminate in a connector that you click into a socket that's connected to the machine. But only one of these machines has the mesh wire modification, so I'm doubtful that the mod is related to the rechargeable battery packs.

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It's shielding for RF interference. You shouldn't have removed it, clearly you don't know much about electronics. Everything you mentioned was connected to GROUND, and it also sounds like a semi-pro did the work. Clearly he was experiencing interference, either generated by or received by the unit.

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mister790 will be eternally grateful.
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