Ok, I'm a bit of a tinkerer by nature which is fortunate since it's helped me resurrect some old Sony/Sharp portable MD recorders. I've also recently been working on some custom Li-Po battery/charger projects. While looking at parts, and listening to one of my Sharp MS-702 recorders, the battery died..well that sucks. I guess I could plug it in, but I had it in my cargo pocket with headphones so I can just get up and go. I've only got a couple of the batteries left that actually worked so I looked on E-Bay and it seems they are getting harder to find (i.e. few listings). The battery is a Li-Ion 800mAh single cell. I wondered if I could somehow rig up a external larger Li-Po battery for very long run time (i.e. more mAh's) I have one unit I received non-working, but rebuilt it into a good player, just never got the record feature working properly. I decided this would be a good test unit. So I set out with the following objectives:
* As little modification to the unit housing as possible
* Retain ability to just run off internal battery or factory charger
i have a bunch of mini JST connectors laying around and thought this would be the best option since it's very small and makes tight secure connections. They are also typically found on Li-Po cells or you can connect your own. I removed the bottom half of the MS-702 shell to find a spot for the connector. Most places had circuits or other ports in the way, or required further disassembly. The best place I found was directly above the existing charging connector. I ran the JST connector leads to the +/- terminals for the factory battery and then super-glued the connector in place. I took a dremel with a small drill bit and bore out a opening for the connector in the bottom shell piece, put it back together and voila!! This thing runs great. I'm thinking about gluing a battery strap to the bottom of the unit (velcro) so I can attach a Li-Po battery whenever I want but not have to leave it there permanently. Maybe this sort of thing might help others out there too, maybe even with different model units. I've attached photos below showing the setup as it is so far. The test battery is a single cell 1800mAh Li-Po battery. With more than twice the mAh's, it should give me more than twice the run-time...we shall see.