Ahh... You can have enough boxes of bits and pieces mate!
Anyway I've just taken apart the wife's Rio ultrasonic facial cleanser which started playing up. It'd charge up then run down within a few seconds or stop/start intermittently. I wondered if the battery pack might be at fault and sure enough it appears to be. There are 3 nimh AAA cells (600mah?) shrink wrapped up to form a 3.6v pack with black and red wires leading to soldered joints on the circuit board. There's some leakage apparent so one or other of the cells has failed. Not being too hot with a soldering iron I thought I might just cut the wires near the defective battery pack and then join a new battery pack to the existing wires. I've seen battery packs like these on Ebay for a few quid but is there anything I need to know when choosing the replacement or will any similar looking 3 AAA cell/3.6v pack do the job?
Oh, and is there an easy way to see whether the item is still otherwise OK before I go about ordering another battery pack? I have some 3.6v li-ion rechargeable AA batteries so could I test the unit very briefly using one of these and just clamping the red/black wires on the relevant terminals? No point wasting time/money if the product is broken now.
Cheers all.