Sachi

I loved my MZ-R900 Sony and used it for some years. Of late, when I took it out, the old battery wouldn't recharge.. the "recharging" symbol would flash and go off after 1 sec. The player plays on the battery charger but not on rechargeable battery or with the additional AA. I bought a new Panasonic battery, and even that won;t recharge. The charger itself works well ( on my Walkman tape recorder too). So what's the problem? Did My MD get too sick? Thanks in advance for your helpful gyan!-Sachi