It blows the fuse each time open the door if this em-Z2100GS

You would better served replacing unit. Throwing parts at it is an unnecessary step.

Some newer microwaves do not have one, unplug oven, remove top, "several screws" on the lower right you will see a circuit board, if you see a silver rectagular capacitor discharge across the 2 points with a screwdriver to remove any additional voltage, near by there should be a fuse clipped in, pop it out and replace with same current rating and assemble before testing because the voltage is lethal and will kill.

Replacement of the lamp should be carried out by a qualified appliance repair service.

YOUR SAFETY IS PARAMOUNT!

Attempt this only if you are competent.

But here is a basic method if you are mechanically minded and have electrical safety knowledge.

The lamp is sat in a housing and its position is adjacent to the vent holes that it shines through.
If you feel confident, disconnect it from the mains power, remove anything in the cavity.
Remove the microwave cover. Purchasing a new replacement lamp will be useful as it will give you an idea of what it looks like. Locate the dead lamp remove the lamp and fit the new one. Replace the covers. Plug it back in and try the lamp by opening the door.
Hope this helps.

you really don't pre-heat a microwave. set it for the time you want to cook and it reaches the temperature for cooking almost instantly

It is most likely that the Magentron has given up in the unit. The cost to repair the unit will exceed the value or cost of a replacement unit.

maybe your magnetro is leaky

A microwave can be dead for many reasons.

It may be the fuse, which is usually located on the floor of the oven behind the control panel or between the door switches.

If the fuse is good, it may be an open thermostat or thermal cutout (TCO) / thermal fuse on or near the magnetron or on top of the cavity / body of the oven.

If it goes dead for a while during or after cooking then comes back on, the magnetron is probably overheating and causing the magnetron thermostat to open.

Then when it cools, it closes the circuit and allows power through again.

When checking thermostats, if it has a hood fan thermostat, that should read open, as opposed to the others, which should read closed.

If it went dead almost immediately after pressing the Start pad, that's usually a shorted high-voltage capacitor.

If it went dead a few seconds after pressing the Start pad, that's usually a failing high-voltage transformer.

If it goes dead or blows the breaker (or GFI) when you plug it in or open or close the door, then there's a problem with a door switch or door switch mount.

If it's intermittent or random, it may be a bad connection, usually on the control board or a loose fuse holder, or even an intermittent fuse.

You should do a continuity test on the fuse while it's in the holder (with the microwave unplugged, of course) then turn the fuse by hand or take it out and put it back in, then test it again.

If you remove the fuse, then press the meter leads against the ends, it can allow internal contact to be made and make a bad fuse appear to be good.

If you or someone you know decide to look into it, we have critical safety information and disassembly information at our site, and our link is at our listing here on FixYa.

For more help from Emerson visit here or get help using your appliance at 1-800-898-9020. Get help locating a servicer or parts at 1-800-695-0098.

Many Emerson microwave manuals are available for free download here.

We're happy to help you and we'd appreciate your thoughtful rating of our answer.

Could be the Magnatron, Diode, HV Cap or Transfomer, some also have a high voltage fuse that blow. Unless you really are confident playing with Very High Voltages, and have a meter capable of 5000v, I dont recommend you repair yourself as a microwave will happily electrocute you. Also if the discharge resistor has burnt out on the cap (assuming it was fitted on your model) the capacitor can store enough power to kill you even when the unit is unplugged so you must discharge the cap before playing with anything else to be safe.

First you check the fuse at the out put of highvoltage of the transformer. If the fuse is ok, replace the magnetron.

unscrew the unit replace fuse near the transformer. this fuse is for heating....