Ramtons inductor cooker model RM381 came in dead, now repaired.

 I received the above inductor cooker in my shop for repair, dead on arrival.

I opened It and did some scanning on the power board, coil, and display circuit and all looked in good shape.

Since the unit was dead I began by checking the state of the main fuse and found it open, whenever you find the main fuse open expect a heavy short ahead.

So, don’t be in a hurry to replace the fuse unless you want to keep the fuse manufacturing company in business.

I continued troubleshooting looking for a shorted component since only a shorted component can cause the fuse to open. Main suspects being diodes, transistors and ics.

Components on this supply are few and therefore testing from the bottom side of the pcb noted a beep on transistor which was attached to heavy metal heatsink.

Cross-section view of the same

I removed the heatsink to access the transistor and noted it was H20PR5, an IGBT, tested dead short both in and out of the circuit.

Unfortunately, I could not get this component in our local market, i ordered it online from AliExpress, which took 8 days to ship to Kenya.

I finally received the part this morning and after replacing, the machine came up smiling.

 

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Thank you guys

 See you in the next class