I'm having problems with a Toshiba Satellite A305-S. The AC converter that is 19v/3.95A doesn't even bring the charging light on. I have tried a Toshiba 19v/3.42A converter. It brings on the charging light, momentarily tries to bring the hard drive on and runs the fan. The monitor stays black the whole time.

Is it possible that this second converter doesn't have enough juice to bring the monitor on?

I'm trying to decide whether to buy a replacement converter and battery for this computer or that's a waste of money.

I've checked the hard drive by pulling it and attaching it with a USB device to another computer. The hard drive seems fine.

the use of a digital multimeter would help in determining if the charger is putting out enough power ,a laptop doesn't need a battery to run if plugged into a power adapter ,so try removing the battery and just power up from the adapter .most good repair shops would have one and could check it for you
whats a multimeter(http://en.wikipedia.org/wiki/Multimeter)

It seemed likely that both the battery and ac converter need replacing- $170 if using Toshiba original equipment. The machine may have additional problems such as power jack, motherboard, or monitor cable. The less expensive alternative was to pull the hard drive, memory, and dvd burner and put them into an older Toshiba. Thank you for your suggestions.