If they are lead-acid gell-cells (not likely given their age) they are probably a lost cause. I have read - and tried - a process which will supposedly restore old gell cells, but I've never had any luck with it. If they are nicads (most likely) there's a chance they can be restored to at least part of their capacity. Can you get to the terminals of the individual cells? Do you have access to an adjustable voltage & current power supply capable of at least 5 amps (10 would be better)? Do you have a voltmeter which can measure in the range of 1 to 3 volts? What voltage do the batteries measure now? What are they supposed to measure? What is the normal recharge time using the Sony charger?
Sorry for so many questions. Restoring rechargeable batteries isn't as difficult or exacting as grinding mirrors, but it's potentially more dangerous, so I want to find out what the situation is before I start giving advice.
Roger Grady K9OPO c21rag@kocrsv01.delcoelect.com