"William Sommerwerck" wrote in message
...
Can you return the oven? You can use the argument
that it's not fit for its intended purpose. Which it isn't.

Nope, my inability to forecast the consequences is not
the fault of the seller.

If your description is correct, the oven is grossly misdesigned. You do
not
implement variable power by turning the magenetron on for 15 seconds, then
letting it sit for a minute! I've /never/ seen a microwave oven that works
that way. My home GE works fine, as do all those I've seen where I've
worked.


I always assumed variable power was simple duty-cycle variation --
pulse-width-modulation -- over a fraction of a second. That the "on"
time
would be fixed at 15 seconds (!!!), with the off time varied, is absurd.
It
would produce exactly the effect you see.

Yep, that's the way most of 'em work. The problem is the filament in
the magnetron. Much shorter and you don't get any power out cause
the filament ain't hot yet. With enough mass inside the oven, it
averages out pretty well. For a single frozen hamburger at 1100W, not
so much.

I've never heard of varying a magnetron's power by adjusting its filament
voltage! I've always ASS+U+MEd there was some way of turning the tube on
and
off by varying an electrode voltage. (Simply pulsing the anode voltage
would
produce variable output.)



All of the bog-standard microwave ovens that I've owned have worked exactly
like that - and it was fine when they were the 'standard' 600 or 650 watts
of a few years ago. However, now they are all 850 / 900 / 1000 watts, it's a
crap system of power control. The one I have at the moment, does exactly as
the poster's does when set to say 60% power. It's like 15 seconds on at full
chat, followed by 20 seconds at full off. 60% is what's needed for heating a
can of soup in a reasonable time to a reasonable temperature. And it's ok if
it's just a full liquid soup like say tomato. But as soon as you try to do
it with anything like perhaps vegetable, 15 seconds of microwaves at 850
watts, is enough to start exploding the peas or beans or barley grains, all
over the inside of the rotten thing. 600 watts didn't used to do this. If
you go to the next step down - ie 40% power - it takes forever to get the
bulk liquid of the soup up to an edible temperature.

Arfa