A while back we bought a second-hand M-Audio Microtrack on Ebay without first checking that its battery was in tip-top condition. On receipt of said recorder, it worked for a few days before failing to boot - effectively rendering itself useless. It is one of those sorry devices, like many of Apple’s, that has an internal, non user-servicable Li-ion battery, which means to get it changed you’re meant to send it back to M-Audio who will charge £50+ for the privelege, and take 3 weeks to do the job - not a particularly amusing situation. So, I thought I’d have a look at how hard it would be to sort myself. As it turns out, it was a relatively easy task requiring surprising simple soldering. It is however dangerously difficult to open the case in the first place …
If you’re thinking of doing this yourself, then be warned - Lithium-Ion batteries can be dangerous - I HOLD NO RESPONSIBILITY for you frying yourself, or your microtrack. If you are competant and cautious, its a simple task, but you do so entirely at your own risk - what follows is a guide to where to start, but seriously, if you’re not sure about this then don’t bother and get M-Audio to fleece you instead !!
![M-Audio Microtrack 2496 [MK I]](http://daz.roughdiamondproductions.com/wp-content/uploads/2008/10/a.jpg)
exhibit A - a dead Microtrack
Cracking the Case
Key to solving the inherent deadness problem is first to get into the case of the device itself. I’ve read of people mangling the audio inputs by using too much force, so take care here. Its not actually that hard but take your time as each time you get it wrong, you’ll end up with a scratch to prove it, or worse still, you could get bitten by the casing snapping back together with one of your digits between the pieces (ouch). Anyway, on the back casing, you’ll notice that the corners are curved around the unit.
exhibit B - side view of half-open case showing position of tabs, and curvy corners
To get in, stick a small flat-head screwdriver between the back panel and the main body avoiding the tabs (marked in red) - the green lines show where its okay to start prising it apart. Do this gently, down the length of one side, and repeatedly lever the case further and further away from the body. Eventually, you’ll see the tabs. When one side is complete, use something (e.g. a kitchen knife) to hold this gap open as you repeat the procedure for the other side - note that there is more space to get started towards the top of the unit on the side with the menu button. A steady hand, and not too much force are whats required, but don’t worry if a couple of the tabs break - not nice, but it’ll go back together again and open up much easier next time …
exhibit C - back panel off, main unit upside-down showing battery outlined in green
The battery is simply stuck to the back of the pcb with a little double-sided sticky tape and can be freed easily. It is connected by one red and one black wire, which can be snipped - one at a time so as not to short the battery. The battery can now be disposed of at your local weee certified recycling centre.
exhibit D - old battery (green) and replacement battery (blue).
Almost any single-cell lithium ion battery will do for this (as long as it will fit in the case once re-assembled) - they are mostly 3.7 volts, which is what we require, and mobile phone batteries suit the bill as they’re small, 3.7v and readily available, the only downside being charge. The original battery is somewhere in the region of 1400-1800 mAh and my replacement is rated at 700mAh, so I expect battery life to be less than half - around an hour of recording time. The replacement battery I found is from an old mobile phone, which on initial inspection was too fat to fit back in the case, so I cracked open it’s plastic case to reveal its interior containing the wrapped lithium ion cell, and a small pcb with the charging circuits.
DO NOT open the batteries any further as you could end up with that nasty lithium stuff plastered about the place (if you don’t know what lithium + water does …)
Anyway, once the original battery is removed, the bare ends of the wires can be soldered onto the replacement battery terminals, being extra careful not to short the battery by accidentally soldering the wires together - a fine pointed soldering tip is probably best, but with care, you can get away with something a little less subtle …
exhibit E - replacement battery with wires soldered, placed in makeshift celophane wallet
Once your ‘new’ battery is soldered to the correct wires its a good idea to wrap it in insulating material so that when its squeezed against the back of the pcb no accidental shorting occurs - I used some celophane from a tobacco packet, and a generous helping of gaffer tape 
So, the new battery is ready to charge. Don’t put everything back together yet as its a good idea to play it safe and watch the battery charge to look out for any signs that things are going wrong - plug the unit into the mains, power it up, and stand back …. If the battery starts to bulge, hiss, whine, or exhibits any other weird behaviour then stop charging immediately, take it outside and stand clear - it probably won’t explode, but if it does, it ain’t gonna be nice - chemical burns anybody ? … see why I say I’m not responsible for your hacking now ?
2 or 3 hours later, the battery will be charged, so remove the power supply, switch the microtrack off, and then test to see that it boots up okay.
exhibit F - the microtrack running from a mobile phone battery
So, now we’ve verified that it is in fact working its time to put the back on. Its worth spending a little time investigating any damage that may have been done to the points where the back mates with the rest of the body as any plastic out of place may hinder the smooth reseating of the panel. Also, bear in mind that the slide switches for phantom power, record level and hold need the back panel edge between the back of the slider and the rest of the case. If the case goes back in the wrong place, these sliders will be mis-aligned making them look weird and hard to operate - and the case won’t close properly, so do this side first, and the second side should (with a little persuasion) easily reseat with a satisfying click.
All in all, that took about 4 hours including charging time, and cost me nothing. If you haven’t a spare battery just lying around it’ll not cost much from places like this. The Nokia BL-6C equivalent is rated at 3.7V / 1070 mAh and at £10 seems maybe a good bet - anyway, shop around as the more mAh you can find (that fit in the microtrack) the more recording time you get.
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