We all carry touch screen computers around in our pockets these days, but before the smartphone revolution, there was the personal digital assistant (PDA). While it wasn’t a commercial success, one of the first devices in this category was the Apple Newton. Today they’re sought after by collectors, although most of the ones surviving to this day need a bit of rework to the battery pack. Luckily, as [Robert’s Retro] shows, it’s possible to rebuild the pack with modern cells.
By modern standards, the most surprising thing about these battery packs is both that they’re removable and that they’re a standard size, matching that of AA batteries. The Newton battery pack uses four cells, so replacing them with modern rechargeable AA batteries should be pretty straightforward, provided they can be accessed. This isn’t as easy, though. In true Apple fashion the case is glued shut, and prying it apart can damage it badly enough so it won’t fit back in the tablet after repair is complete. The current solution is to cut a hatch into the top instead and then slowly work on replacing the cells while being careful to preserve the electronics inside.
[Robert’s Retro] also demonstrates how to spot weld these new AA batteries together to prepare them for their new home in the Newton case. With the two rows fastened together with nickel strips they can be quickly attached to the existing electrical leads in the battery pack, and from there it’s just a matter of snapping the batteries into the case and sliding it back into the tablet. If you’re looking for something a bit more modern, though, we’d recommend this Apple tablet-laptop combo, but it’s not particularly easy on the wallet.
I have a MessagePad 110 is has 4 AA batteries in the back so no need to make a pack for this version, don’t know about the others
yes, the earlier 100-series newtons were designed to run off standard alkaline batteries, and the 110/120/130 also supported a rechargeable “battery pack” that was literally just a set of 4 AA NiCads taped together.
The 2×00 series was designed to use NiMH cells from the get-go, which are generally superior to NiCad but a lot less forgiving about how they’re charged. This explains why their new pack design includes a thermistor and thermal safety fuse, but not why they made the thing so damn annoying to get open (or why they made it impossible to just swap in alkalines without an adapter).
The reason for making it impossible to open the case is written by yourself: the safety measures for the battery’s sake. At that time, replacing NiMH batteries would also mean that the thermistor should make sufficient contact and the thermal fuse stays in place. Fat chance a large number of users would screw those two safety measures making the battery the weak spot. At that time, many designers thought the NiMH battery had an eternal life span so replacement wouldn’t be needed, hence this solution.
Same for my MP 120, except the plastic clip on the back is broken so I have to use a bit of tape to keep it on. There’s two small metal strips on the rear, are they for charging batteries?
They’re for charging the batteries in the Newton when the Newton is on its charging station.
Frank from pda-soft.de
When i` the video does he show welding the batteries?
around 16:41.
i was hoping to find info on the thermistor. i lost mine and am in the same situation. although i managed to split the pack on its original seal lines. there is a intricate seal curve around the exposed negative terminal though.
Thanks!
I didn’t want to watch the whole video as I don’t have a Newton.
So, it begins after 12:44 on the video, he is using a cheap(?) spot welder
probably from Aliexpress. I was hoping for a more homemade solution.
If you want s home made spot-weld, check out k-weld.
Thanks, but I just got a winning bid on a battery spot welder on That Auction Site last night! Hopefully it will be good enough that I won’t have to build one.
As a matter of fact this is not a thermistor, but a so-called polyswitch called LTP 190. They’re kind of self-resetting thermal fuses. The pack will work when the battery contacts are bridged instead, but you’d be challenging fate since there’s no protection when the pack is shorted out from the outside.
Frank from pda-soft.de
been sold on newtonsales for the last 20 years and they have also 3d printed perfect replacement battery housings that can be used as either battery packs or trays for batteries.
Nice video. And he does credit Frank at
https://www.pda-soft.de%2Fbody_mp2k_battery_pack.html
for where he got his start
I still have my two MP2000 pda. One has this NIMH battery pack and one has the AA alkaline holder. Theyre great machines but a bit slow compared to modern handhelds.
spot welding batteries is a miracle. that’s the thing i hate the most about nimh and alkaline: in my life they come in these modular corroded-contact formats. best time i ever had with nimh was when i soldered onto it