The battery in My Sony DSC-P1 digicam is some years old now, but still
serving me well. Its NP-FS11 Lithium-ion battery has specs: Max V =
4.2 V; Nominal = 3.6 V; Capacity 4.1 Wh. Its charger has suddenly
expired, so I'm seeking advice on either getting to its innards and
fixing it, or safely using my home-brew DC power supply while I shop
around for a replacement charger. I'm a bit unsure of lithium-ion
requirements and tolerances, and as these batteries are pricey I don't
want to risk damaging it.

The charger is a model AC-LS1A and has specs:
AC IN: ~ 240 V, 50 Hz, 11W
DC OUT: 4.2 V, 1.5 A

Mains AC is reaching the charger OK, but at the output plug there is
no voltage, and DC resistance is off the 20M scale of my DMM, so
presumably open. The output cable is integral, cannot easily test for
continuity, but it *looks* OK.

1. What is best approach to get into the case? Hacksaw? Or any secret
spots to drill which might reveal screws?
2. Any 'obvious' causes?
3. Could I safely connect to a 4.1 V DC source from my bench power
supply? At what optimum current?

Any/all advice would be much appreciated please.

--
Terry Pinnell
Hobbyist, West Sussex, UK