Induction Cooker Repair
This Induction Cooker was brought to me with the complaint that it is intermittent, and some of the control switches do not function. After opening and doing a thorough cleaning of inside, PCB and other parts, I removed the main board for visual inspection and troubleshooting.
I noticed that the solder side of the PCB was covered by varnish and I could make out a lot of dry solders.
I also removed the 0.27 mfd Cap connected across the coil. See what I found:
Here is the picture of the other side, which is after removing the large high voltage capacitors for check up:
I removed and checked the other high voltage capacitors on the board and could not find anything wrong with it and these were reading perfectly well. ESR was also ok.
So, started the process of cleaning the solder side of the PCB to remove the varnish to retouch the dry solder points. After several attempts of applying Thinner and rubbing with Metal Brush, and scraping with a knife in certain places, I could succeed in exposing the solder joints. Retouched all the points with fresh solder. Checked the ESR of electrolytic capacitors on the board (about 6 of them values of which were 100/25, 4.7/450, 4.7/63 etc.) and found them to be either at the brim or exceeding. So, replaced all the 6 electrolytic capacitors.
Checked the switches on the control board and found these were showing resistance, when pressed, indicating improper contacts. So replaced all the 6 defective press-to-on button switches. Since the buttons were slightly longer than the one on the board, I nipped the extra length with a tile cutter tool. Here are the pictures of the tool and the defective switches and the control panel board after replacement (before nipping the extra length).
After completing the work, put the PCB and other parts back into the cabinet:
Connected the control board, and kept the top of the Induction Cooker without screwing. Tested it keeping a vessel with water and switched it on. It worked very well and all the switches were also functioning properly.
Fixed the back screws and did polishing and cleaning of the surface and made it look like a new one. Another job completed satisfactorily.
This article was prepared for you by Parasuraman Subramanian from India. He is 66 years old and has more than 30 years’ experience in handling antiques equipment Valve Radio, Amps, Reel Tape Recorders and currently studying latest techs classes conduct by Kerala State Electronics Technicians’ Association. He was a BBA graduate, retired as MD of a USA company.
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You may check on his previous repair article related to Induction Cooker below:
and also his previous latest repair article: