My unit sounds like popping corn when I turn it on...there were a couple of puffs of steam out from under it at first...there is also a film of some kind of oil product on the bricks around the heater...looks like it is probably coming from under it but not sure.....needless to say, until I find out what is causing the unit to make that sound, it will remain off....anyone know what the problem is?

SOURCE: Delonghi "The Incredible Heat Machine"

blows the house fuse after being on a few minutes

SOURCE: MAYTAG MMV4205BAS Running but not heating

If the food in the cooking compartment is not heating at all, then you may have one of several components related to microwave energy generation that have failed or became disconnected internally.
Magnetron Tube, HV Capacitor, Filament Transformer or any number of sensors that disable power to the system. The control board could also cause the system to noty function correctly.. You wanted general inputs.. there ya go.. LOL
Not sure I told you anything you didn't already know but you should ask the tech what he did after he gets it going...
Regards,
Rick

SOURCE: TV made popping sound and then shut off

You need to look in your owners manual for the telephone number and order a new bulb. It should cost about $200, but they will ship it overnight and minimize your downtime.

I've replaced 2 in my WD-52525 in the last 3 years, the first one went like yours did, very suddenly, with an audible POP!! The second one was preceded by an orange warning light, which the book says is a warning that the bulb has about 20 hours left on it.

To replace the bulb, UNPLUG THE TV, remove the left speaker screen, with a philips screw driver unscrew the bulb, pull it out by the handle, then replace it with the same type, in reverse order. This is a very easy replacement that does NOT need to be done by a service technician to complete.

SOURCE: clicking/popping noise from rear a/c-heater unit

It's the temp blend door actuator.

SOURCE: oven comes on and than you hear a puff /pop sound

The problem is usually the igniter not reaching the correct amp draw .When the igniter does not reach the correct amp draw it may allow the gas valve to partially open or not open at all. The igniters are inexpensive and easy to replace. This video will walk you thru the correct procedure for testing an oven igniter. It may be a different model but the testing will be the same.You can also enter your model # for diagrams and illustrations of your specific model. Not all models are available. All parts come with installation instructions.