How to get the shit working

Previous repairman for some unknown reason came to the conclusion that it's all in the transistors. Absurdly expensive ones, by the way. Replaced them before me, but, thank God, "burned-out wrong" ones were not thrown away - they came in handy later when I, not having a scheme and not having the desire to reverse engineer all this schizoid (e.g., generator unit, which includes a bunch of processors and ROMs, connected to the block "control", where only a few buttons, bulbs and a variable resistor, with nothing else, as a full RS232 interface!) nonsense, began to repair the gourmet shit with tries, and mostly errors method.

Generally, while I was looking for the fault, the "glamorous" transistors successfully burned out.

By the way, it was a faulty diode, charging the floating power driver of one of the FETs, and the connected in series with it resistor died too.
Well, you know the bourgeois parts - unlike the anti-democratic Soviet ones, their fault is difficult to determine by appearance, so had to torment (the infamous burzhuiny refused to provide the scheme) until found...

Diode (at the photo - bottom right, near to the mentioned resistor) likely died as a result of overheating - it was too close to the 4-kilowatt transformer. Later, the possibility of any overheating has been eliminated - I added lots of holes and a powerful fan.

In general, incompetent bourgeois scheme had a lot of crap - for example, after the rectifier bridge two capacitors as much as 330 uF were placed! Well, the professionals understand what it means to 4-kilowatt device when the main grid is 50 Hertz. Those kind Germans even installed a special fan to blow to the poor capacitors...

Of course, I added some capacity - well, I had a 600 uF capacitor - not enough, of course (Should be about 4,000 uF, but 1200 was quite sufficient.), but it worked - the capacitors as by wave of the magic wand became cold.

The additional capacitor is glued into the corner between the bottom and the aluminum cube.

Poor linear voltage regulators 15 and (especially) 5 volts also have escalated to a bad temperature - scheme is stuffed with unnecessary and expensive ROMs and processors, but the Germans have stinted on winged metal for the radiator, although abundance did not regret it on the shild - another stupid thing to do, ferromagnetics are cheaper, and shield the electromagnetic fields (which are there in abundance - the same 4 kilowatt transformer is a good source of such interference) much better.

it was

so it became

Had to find some aluminum piece of metal and made a normal radiator. Can't remember offhand, but I think I also replaced the 15 volt regulator to 18 volt one - the higher the voltage on the gates, the lower the resistance of the transistors.

In general, the German garbage was modeled as a hit - we all know how dangerous it is to reduce the opening voltage on the gates, and all FET drivers even have a special protection against it - UVLO, which, incidentally, was constantly worked in this garbage, however, owing to two main reasons, first among which is insufficient output voltage of the transformer, feeding the signal circuit, and the second is absolutely pathetic capacitance after the rectifier the secondary voltage had to increase it 4 times to avoid drawdowns voltage of 15 volts. It refers to the capacitor, which is seen to the right of the radiator.

This, incidentally, was the reason that all this garbage moldings refused to work immediately after the purchase - we're not a Germany, and the voltage is not necessarily exactly 220V (and they seem to be counting on the 240 and 60 Hertz) volts. Strictly speaking, after the discovery of this mistake I would have this transformer to replace with a some with output voltage of 18-20 volts, but there was not anything suitable at hand, and actually the stabilizer was already purchased.

I also suggest this transformer replacement.

However, completion of the electrical part is over.

For normal cooling a lot of holes were made

The screen also had a lot of punch.

Had installed an additional powerful fan that blows air into the case.

And that's how I hooked it.
Standard holes in the case (yoy see them under the copper fittings of the radiator) had to stifle - they interfere with the proper airflow direction. It is not so noticeable in this photo because I stuck them with a transparent film.

Now, about the mechanics.

Well, those who studied in the normal Soviet school, remember the essence of the transformer, including those, having no magnetic core.

The old Germans also remembered the design of the transformer and in the good old days did everything carefully, with observance of the ordinary laws of school physics.

Well, you can NOT load the transformer to short-circuit!!!

Yes, the design of the holder of the crucible of metal. Framework type. Metal conducts electric current. What now? Short circuit?

So in order to break this parasitic closed loop circuit, which forms a frame, usually at least one gap must be provided, and the normal old good Germans knew it well enough.

That's how they did

"New Germans" too, probably, initially wanted to establish at least one loop break.

but a mixture of stupidity and self-righteousness didn't allow them to do.
Obviously were going to, but then changed their mind - why to do good and correct, when is possible to do wrong. Oh, those new Germans...

Okay, we fix this.

For reliable rupture of the circuit puts a PTFE or PET where possible.

Moreover, the desire to install in the wrong place pontovityh overlay with laser milling (well, who needs this is not a cheap operation?) logo this disgraceful "company" was created one circuit, which in some way managed to escape by breaking out of this new short-circuit by installation of PTFE gaskets under the screws and between the rod and guide.

In the end, it looks like this.

But okay, what about work contour? Don't forget, it runs about 500 amps - very robust design current. You generally represent, what is 500 amps?
Well, it is about 20 times higher current than the current of the electric - so there's all that copper, fat, and in addition, water-cooled.

Have you ever had to deal with the fact that the car does not start only for the simple reason that not enough for good contact on battery terminals? Don't forget, there's only 200 amps, but it is 2.5 times less than what it should be in this loop.

Now let's look that up for us burzhuiny at the request of workers.

Actual size of this "contact" - a couple square millimeters, enough it for 500 amps, what do you think?

Therefore, taking and mending. Flux, solder, torch. A soldering iron will not help, copper is too thermally conductive material.

Here, it is now.

Assembly, check.

Well, it can if it wants!

Some urgent work has not been done...

The fact that crucible is made from a porcelain, much harder than copper, which the coil is made from .
Moreover, it has a very rough surface, and if we allow him to rub the coil, sooner or later it will protocil a hole in it. Here we must not forget that the copper tube, which a coil is made from, is filled with a water under pressure.

Thus, after the crucible will protocil a hole in the coil, the whole scheme will be immediately flooded with water and then will burn out.

The old good Germans knew it, and specifically called for the pin, which uniquely captures the crucible relative to the coil and does not allow to it even to touch (well, and so less heat loss during melting) the coil.

"New Germans" "don't know" this - they have the crucible it's always about coils, and one coil pretty much rubs it.
Therefore, burnout of the scheme over time.
But I had not solved this a problem - it required a lot of efforts, and I was in a bad mood - I got only 5000 RR ($ 160 at that time) for the real recovery of this junk device.

By the way, after the rework this garbage stove for about 8 years now works without problems, although a couple of years ago had to repair the lid lock - also unnecessarily complicated and unreliable part.