Dell Dissection: The Axim Battery Latch Problem

(If you found this page when Googling for a solution to the Axim battery latch problem, there is a non-surgical solution which you’ll find at the end of the article.)

Starting about six months ago, my Dell Axim x51 began to display intermittent “Battery latch was opened” errors. This error causes the Axim to automatically turn off, presumably to prevent data loss if the battery tumbles out of the unit. However, considering that the battery is embedded so firmly that it takes considerable prying to coax it out, this is a rather heavy-handed solution to an unlikely problem.

For some reason, the problem recently escalated from a once-a-week nuisance to a regular occurrence. Any physical contact with the unit while it was turned on, such as pressing buttons or closing its metal case, was likely to trigger the error. When the Axim began making plaintive “latch was opened” beeps while sitting in my pocket — powered off — I couldn’t ignore the problem any longer.

The battery latch. Looks closed to me!

As shown on the right, the Axim battery latch is just a simple slide switch on the lower back of the unit. It is normally set to the right to lock the battery cover — in order to remove the cover you have to slide the switch to the left. On my Axim the switch and battery cover looked perfectly normal and didn’t seem to be loose. Some exploratory surgery was called for.

Screw locations

As with many consumer electronics, the Axim can be opened by removing a few screws that are hidden underneath the rubber feet. The 4 feet are circled in yellow in the image on the left. They are stuck in place with adhesive, similar to tape, and can just be peeled off using your fingernails.

A screw uncovered

The screws have a star-shaped “Torx” slot (specifically, a T5), as you can see in the image on the right.

Torx screwdrivers are pretty commonplace these days, and you can likely find one at any Radio Shack or electronics supplies store. You’ll likely find that, if you’re careful not the strip the slot, a tiny slot screwdriver, such as the one in eyeglass repair kits, will also do the trick.

Before going any further, you should remove the battery if you haven’t already. The battery should have a ribbon underneath it to make this easy — just tug on the ribbon and the battery will lift on the left side, allowing you to swing it out of the compartment. The 3rd party battery I bought came with a thin ribbon that tore the first time I tried to remove the battery, so I had to insert a small slot screwdriver in the lower left corner of the battery slot to pry it out.

The backup battery

By the way, don’t spend too much time exploring the innards of your Axim with the battery removed. The circuit board has a small wristwatch-type battery, as shown on the right, that takes over when the main battery is removed or drained. I’m not sure what happens if you run down the backup battery, but I bet it isn’t good.

Once the screws are out of the way, you can pry open the 2 halves of the case along its seam. There is nothing but friction holding it together, so you don’t have to press tabs or remove adhesives or anything like that. The battery latch is, of course, on the back side of the Axim, but out of curiosity I also removed the front side cover to have a look underneath (and clean out the remnants of 3 years worth of cookie crumbs and pizza crusts).

While the patient is lying there, open and vulnerable, let’s have a look at its private parts.

Here is the back side. The battery contacts are circled. In the foreground is my surgical instrument of choice, the pipe wrench.

I see Paris, I see France!

And here’s the front-side. Those silver discs on the left are the contacts for the buttons underneath the Axim’s screen. The button contacts are quite sturdy, so if you ever have a problem with those buttons the cause is likely with the plastic buttons on the inside of the case.

Full frontal

And here are those case buttons – flimsy rubber contacts, like the underside of a keyboard.

What lies beneath

Here’s a shot of the upper left side of the Axim, showing the contacts for the lock switch (yellow), Bluetooth (or Wi-fi) button (green) and record button (red). These are relatively fragile – a standard electronics slide switch and momentary push buttons. I’m not sure what the thing marked in blue is — I’d guess that’s it’s a Wi-fi antenna, except that this Axim model doesn’t have Wi-fi. Bluetooth, perhaps. Whatever it is, you can see the plug that attaches it to the mainboard.

A switch, 2 buttons, and the mystery object

Back to the battery latch problem. The latch mechanism consists of a black, curvy piece of plastic connected to the latch switch, marked in yellow below. The curves fit snugly against another piece of plastic. When you move the switch from right to left, the plastic slides horizontally, with the curves locking into another position, similar to the latch on a fence gate. All of this seemed to be working normally. When the switch was in the closed position the latch was reasonably firmly locked — as firm as a 1/8″ piece of plastic was likely to get anyway. The latch is held in place by a couple of black screws. I suppose that the “battery latch open” problem could be caused by a broken latch, or loose screws, but neither was the explanation in my case.

21st century battery latching technology

As you have no doubt noticed there is little white square thing stuck to the latch of my Axim. This is not a moldy cookie crumb or a giant booger. (The boogers are the smaller flakes around it). It is a flimsy piece of foam rubber, stuck to the latch with a bit of adhesive, whose purpose is to hold down the battery latch sensor. The sensor is a stiff surface mounted switch on the mainboard, circled below that is held to the right when the latch is closed.

OMG!! The battery latch is totally open!

Yes, that’s right, the all-important battery latch that absolutely positively needs to be closed for the unit to remain in operation is held in place by a DINKY PIECE OF FOAM RUBBER.

This, I think, was not a great idea.

Given that the battery latch sensor is pretty much pointless considering how difficult it is to remove the battery, I considered soldering it so that it would be permanently locked in place. I chickened out — soldering a circuit board seemed like an unnecessarily invasive bit of surgery for a problem caused by a decidedly low-tech design flaw. I later discovered that someone had solved the problem by removing the sensor altogether and replacing it with a solder jumper, so it’s good to know that a surgical option is available if necessary.

A non-surgical solution is to apply some extra pressure to the battery latch sensor when the switch is pushed to the right. As you can see from the picture below, there are 2 plastic tabs that are visible from the outside of the Axim case. These 2 tabs are slid to the right when the battery latch switch is closed. The tabs push down on a plastic strip, which pushes the foam rubber into the battery sensor. So, the solution is to buttress the plastic strip so that more pressure is exerted when the plastic tab is switch to the right.

Clippy to the rescue

I selected a paper clip. An orange paper clip, to be exact. I snipped off a u-shaped piece about 3/4″ inch long and slipped it into the crevice beneath the tabs. Admittedly, a paper clip is not the most sturdy possible latching mechanism, but compared to a DINKY PIECE OF FOAM RUBBER IT’S THE FREAKING ROCK OF GIBRALTAR!

Believe it or not, it worked. It’s been a week now with no battery latch complaints, not even if I remove the battery latch and shake the Axim like a maraca. Snap!