Sony Ericsson DISCHARGES when plugged in I have a Sony Ericsson Live With Walkman (WT19i). About a week ago my phone started discharging when plugged in for charging using either a Samsung wall charger or the USB port on my PC. It charged slowly but correctly when it was turned OFF, but dropped down to zero rapidly from 60% charged state when plugged in ON state.

I fail to understand the reason for this as the phone works correctly when not charging (battery appears to be intact and not leak charge on regular use).
Try using a Sony Ericsson wall charger. Because standard USB can't supply much power, manufacturers often use off-spec currents and/or voltages in their wall chargers in order to charge the device faster. Because they're breaking the standard by doing this, sometimes a wall-charger for one manufacturer's device can't supply enough current to a different manufacturer's device.

This isn't specific to Android devices, but any device that charges using USB. For example, many iPhone and iPad users have noticed that their Mac charges the device faster than a PC does, because the PC has a standard USB port, but the USB ports on recent Macs can recognise that they're connected to an iThing and supply extra voltage and current.

If you don't have a Sony Ericsson wall charger, follow Izzy's suggestion and make sure to keep the screen turned off when you want to charge.