If you turn it off switch the wall socket off, hit the power button a couple of times until it stops flashing the power button as though it is trying to power on. leave it plugged in for a day with the power turned off at the socket it should bleed the stored voltage out of *most* parts of the machine.

And as far as logic board circuitry goes, you shouldnt be overly concerned about the caps there as most of it is pretty low amperage anyway.... If you dont touch it whilst it's running (basically impossible... you shouldn't have a lot to worry about. It's the PSU and AV circuitry that is the most sketchy and still requires care as the amperage (which is the deadly part of electrical current) is a lot higher, and even with the bleed-down resistor functional, the CRT particularly can still sometimes store a residual charge for a while that might not be enough to kill you (though it can if it takes the right path or you have cardiac or certain neurological conditions), but will nonetheless knock you for six.

You have to be very clumsy to kill yourself with residual charge from a power supply circuit, but even I am very light footed around CRT circuitry, transformers and tubes. There is a method to disharging CRT's that is quite safe so long as you have the correct tool and adhere strictly  to the procedure and dont allow yourself or an uninsulated conducter you are holding become a short to ground. There is a fair bit of info on all this on the web if you feel like enhancing your skill set... if you arent comfortable still though, it may be best to avoid the area of high voltage, high current areas.