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Discussion Starter #1
Hi guys!

I have purchased a 2005 Induction/Gas cooktop from a friend. According to her, the fan and induction hobs were not working, only the gas. There were no manuals available so I went ahead and opened the unit. I discovered that the copper on the motherboard right at the power supply and cooling fan was melted. I went ahead and installed a thermal fuse and bridged the damage.

I also discovered that the marking on the back plate showed 220~240V, 50HZ, 0.5W-4.6kW. The cooling fan sticker showed 240V 60HZ 20W isol. We have 120/240V 60HZ supply. The unit has 1 black, 1 red and 1 green wire (ground).

Any ideas on how this might be wired?

Noel
 

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Wire it for 240 volt. Red and black hot and green ground. I would test it before I installed it. Being it has a 60Hz fan motor, someone must have replaced the original.
 

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The melted PCB trace is unlikely to be the real problem, just a symptom of the real problem: a short in some semiconductor device. Most likely an IGBT, MOSFET, or diode has failed. Powering it up again without identifying the real problem may cause more damage. But once you have fixed it, 60Hz power should be fine. It converts the incoming AC power to DC first anyway.
 

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Discussion Starter #4
While I was cleaning the burnt residue on the PCB I discovered that the black wire was labeled L (I assume Live), and the red wire labeled N (I'm assuming neutral). I read somewhere that this was the color coding for european wiring before 2006. I am assuming then that wiring both red and black as hot would not be the right option. If so, I have to purchase a step-up transformer to make this work.

I also discovered that the power relay (1 of 2) for the induction coils was somewhat burnt out (char marks inside the housing). I will test if the part is still OK as well as the semiconductors this weekend to see if there is a problem there as well. I'm thinking now that there might be an overvoltage issue due to improper wiring in the past, or maybe the constant switching from low to high power which eventually caused overheating and short (but its an induction cooktop, which should be normal use). I'm not an expert so I could be wrong on all counts. Thanks for the feedback guys - I definitely would want to solve this and get the cooktop wired!
 

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It sounds likely that the switching device (IGBT or MOSFET) failed, possibly as a result of the resonant capacitor failing first. This causes a direct short across the incoming line, through a bunch of other components. There may be quite a few damaged parts. You're right on the wiring; 240V between black and red. You don't need a step up transformer.
 
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