Brett Miler wrote:

I understand at one time you couldn't take apart a TV set because
supposedly it held a charge and could kill you. It may be true, or
not, I don't know.

Now I have a microwave that went FUBAR. First the LCD didn't work
correctly. You couldn't read anything. Then it would start and stop
for no reason. Finally, the thing blew out "electrical fire" inside
the microwave. Now it will no longer heat food.

So, since it is bad, I wanted to let my kids disassemble it for
education purposes. Do I need to wait for the unit to discharge
before allowing them to mess with it? It has be unplugged for around
2 weeks.

It's probably safe by now, but don't take chances. There's a large high
voltage capacitor, approximately 2" x 3" x 1", that can retain a few
thousand volts indefinitely if its bleeder resistor fails, and bleeder
resistors do fail. It must be discharged by unplugging the AC cord and
then shorting the capacitor's 2 terminals together with a
plastic-handled screwdriver (merely wrapping a metal screwdriver handle
with electrical tape is NOT adequate). But this may not be possible
because of the physical placement of the terminals, in which case each
terminal should be individually shorted to the oven's chassis. Do this
by wrapping some bare wire around a screwdriver shaft and connecting
the other end of the wire securely to bare metal inside the chassis
(you may have to loosen a nut or bolt to insert the wire under it and
then tighten for a good connection). Then and only then touch the
screwdriver's metal tip to each capacitor terminal.

If the high voltage capacitor isn't discharged, it can be a much worse
hazard than a picture tube, despite the much lower voltage, because at
least the picture tube won't put out a lethal level of current, as a
microwave oven capacitor can.

There is no radiation from the magnatron tube when the power is turned
off.

Do NOT let your children play with the large transformer, which puts
out 1,000 volts when plugged into 120VAC. So after discharging the
oven's high voltage capacitor, clip all the transformer's wires flush
so it can't be used. Some ovens may instead have a high-frequency
power supply with a much smaller transformer on a circuit board. I
suggest removing that as well and destroying it.

The magnatron tube has a pair of large ring magnets that most people
want. They're epoxied to the metal body, but at least one magnet may
have cracked by now.