No heating in Avon Induction Cooker VQ16 solved!
This induction cooker was brought to me by my friend with the complaint that it was getting on, but did not heat. I opened the cover, did a thorough cleaning. This is a simple task. Remove the screws from bottom, remove the mains cord from its sockets, remove the coil, disconnect the sensor and disconnect it from main board, disconnect the fan and front control panel, and unscrew the main board from the bottom cover.
First thing in Induction Cookers is to look for black, large sized box fixed capacitors located at the output where the coil is connected, as these are found to be common failures. I removed these two capacitors for checking. See what a 0.3uF/400V capacitor was reading, first on Blue ESR meter and then on Capacitor Meter:
The other one, 5 mfd/400V though reading ok, had the bottom slightly bulged. This is an indication that it might fail any time. So, replaced these two and and checked the IGBT for any shorts, which might not be there, as the fuse was in tact and the unit was getting on. Reconnected the panel, coil, mains cord, fan etc. And switched it on, placed a stainless steel round vessel with water on it and touched the function button. No heat, though the fan was running.
So, I knew that there were more failures on the board. So, switched it off, dismantled everything once again, and removed the board for thorough investigation. I noticed that there were many rusted components on the board; a few IN4148 diodes, S8050/8550 transistors, 78L05 regulator which looks like a transistor etc. While removing, the legs broke as it had reached that condition:
After replacing these and doing a thorough dry solder patch up, and checking important spots where high watt resistors are used, I assembled the unit again and switched it on by placing a vessel like before. It started working, and slowly heating up. But all of a sudden, I heard a loud noise and spark from underneath and the unit became dead! Smoke and burning smell came out!
So, I switched it off and dismantled the unit once again.Noticed that the fuse was in tact (!!!), but IGBT was short, PWM IC Viper12A had cracked, a 10 Ohm 1W resistor was charred. As is common in Induction Cooker Main Boards, some values of components have gone high or low and this needs more thorough probing. So, I removed one leg of all the resistors and diodes on the board.
Checked and found the value of a few resistors had gone high. Then replaced all the electrolytic capacitors and suspected fixed capacitors as well. Checked the diodes and transistors and found these were ok. Looked for any track cuts and checked thin tracks using ESR Meter, as suggested by Jestine Yong in his article on more use of ESR Meter (This meter was bought from him). Found everything ok. Replaced burnt out components like IGBT, PWM IC, and defective resistors and fixed capacitors etc. Following are the components totally replaced in this ‘failure-monger’ Induction Cooker:
Cleaned the board thoroughly using Denatured Laboratory Spirit. Disconnected the jumper that goes to IGBT and connected only the control board and fan and switched it on. It worked fine. So, soldered the jumper, and assembled the unit back again. Switched it on! I heated two vessels of water on it and it worked very well:
Before concluding, let me share this for the sake of novices on Induction Cooker (Perhaps Jestine Yong can come out with a book on servicing Induction Cooker and Microwave Ovens) that Induction Cooker works on two or three types of Voltages. Primary B+ voltage is derived directly from the 230V AC rectified by high Amp rectifier modules and smoothed by the high voltage fixed capacitors. For the PWM controller, series of high watt resistors are connected from AC line and rectified by diodes and smoothed by a suitable electrolytic capacitor, to reach the required DC level for its function. When it starts working, it is induced to the primary of a small SMPS transformer, from the secondary of which power supply to the micro controller and control panel etc. are given. On switch on, switching of the IGBT is achieved to produce high frequency electromagnetic field around the coil, which is transferred to the vessel and sets up a circulating electric current, that heats up the vessel.
The main difference between microwave oven and induction cooker is that the oven heats the contents whereas the IC heats the vessel. That is why in microwave ovens, only suitable plastic containers are to be used. For more details, please visit this site: http://theinductionsite.com/how-induction-works.php. There are replacement boards available for induction cookers and I am giving below the snaps of these along with a spare coil I have, for your information. I tried this on the IC under repair and it was working fine. When any board is so stubborn and cannot be repaired, the ideal way is to replace the board with these.Unfortunately, only press to on switch type control boards are available and not touch type.
This article was prepared for you by Parasuraman Subramanian from India. He is 65 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 and presently working as Consultant Manager, Purchase & IT, in Irinjalakuda Cooperative Hospital.
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You may check on his previous repair article below:
https://www.jestineyong.com/protect-mode-in-yamaha-c4-pre-amp-solved/
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Corriete
December 12, 2015 at 7:07 pm
great article. keep doing the good works saving from the dump.
Albert van Bemmelen
December 12, 2015 at 8:21 pm
Thank you very much Mr. Parasuraman. Very informative repair! Not something we read about easily either!
Robert Calk
December 12, 2015 at 8:27 pm
Good job, Parasuraman. And thanks for the link.
Yogesh Panchal
December 12, 2015 at 9:38 pm
Good job! Sir.
Henrique J. G. Ulbrich
December 12, 2015 at 10:51 pm
Very good, Mr. Subramanian. i checked the link you've suggested about induction cookers and enjoyed it a lot. Very didactic. Thank you.
Hicham
December 13, 2015 at 7:58 pm
Very good, Mr. Subramanian, thanks for the link.
Paris Azis
December 14, 2015 at 5:43 am
Hello Parasuraman
I really liked this one very much. This was my turn to learn from you, as I have never been involved in such a repair. I know the principals of induction heating, I also confess that I recently freaked myself out viewing a large number of relevant videos in “you tube” and I intend to experiment with this electromagnetic effect. As a topic it is really amazing…Thanks for the link as well.
I have also some questions or even reservations about using this method for cooking. This has mainly to do with possible side effects against personal health using this (or similar) method…For example low frequency electromagnetic radiation it is already well known that causes cancer after long term exposition to it. Do you know what the frequency range in which they operate is?
I have seen an inductive cooking machine once before and I strongly remember that I could hear a humming 50Hz noise coming out of it “loud and clear”…
Thank you in advance
Parasuraman S
December 14, 2015 at 5:58 pm
Many thanks! In the same web link, please browse, you will come to Pros and Cons of IC. I am providing the link here http://theinductionsite.com/proandcon.php, in that under Radiation Hazaards, they say 'Radiation Hazards?
Owing to the length of quoted material involved in our discussion, we have put this topic on a page of its own; but the real scientific literature seems to show rather clearly that there are simply no radiation-associated hazards, even for those with imbedded cardiac devices. The fields are very localized, and in any event the cooking vessel absorbs virtually all of the field energy (and if there is no cooking vessel on an element, it won't turn on). You should certainly read about it for yourself, but claims of hazard seem quite groundless. The frequency is between 20-100Khz, if I can go by this link: https://www.google.co.in/search?q=what+is+the+frequency+of+induction+cooker&ie=utf-8&oe=utf-8&gws_rd=cr&ei=I5JuVuCMC4GluQTcmYaYBQ
Paris Azis
December 15, 2015 at 6:32 pm
Hi Parasuraman
Thank you for the explanation. I will visit this site for further info.
All the best!
Albert van Bemmelen
December 15, 2015 at 4:13 am
Hi Paris. You tell me something I didn't knew about low frequency electromagnetic radiation. At least the fact that it is proven. But I have read or heard on tv that Television Repair engineers often got Blood Cancer (Leukemia) from their work. And Mobile (Smart)Phone repair men assumably got ear cancer. Maybe we all should start with making electromagnetic sealed homes, because Wifi and other EM sources have very much increased in the recent years. When someone would introduce Aluminium Wallpaper on the Market that would protect from outside RF and/or EM radiation, maybe it even would help to sleep better at night?
Paris Azis
December 15, 2015 at 7:22 pm
Yes, Albert, this story about L.F radiation is known long ago. Especially as regards radiation from high a.c voltage distribution lines. A very impressive experience I had at about 20 years ago was the info I got from people working in power distribution substations, where huge transformers are used to step down the incoming high voltage before distributing in households etc, referring to the gigantism phenomenon of various plants including plain grass in the yard of them, caused by the EMI field! And that is the reason they have a lot of rabbits free there. They are needed there just to eat as much grass as possible keeping a natural balance!!
Furthermore the TV repairs’ case has mainly to do with the soldering procedure and especially with the fumes dispersed around the working environment. This refers directly to lead based solder and it needs as a countermeasure the use of a fume extractor in order to eliminate the hidden possibilities for these fumes to be developed in this sickness.
Lately I read about not only ear cancer but also brain cancer as well, hitting cell phone users that do not make use of a bluetuth device or those cable earphones provided with the cell phone, while “they talk too much”. And finally you are right about the “radiation garbage” you describe but should we live in EMI isolated Faraday shields? Not so easy question to be answered…
And as a good habit I always switch off my WiFi device at night. At lest this disease has to do with the magnitude of the resistance each individual presents in terms of health strength, and this is something, although it does not resolve the issue radically.
A secret in our life (I paid a lot to learn it!) is to always try to find and apply the happy medium per each case and avoid entering in a vice cycle instead…
Best Regards
Dr. Bist
December 14, 2015 at 3:45 pm
nice article
Goh K S
December 15, 2015 at 3:11 pm
Cost of induction cooker has dropped considerably overthe past two years, so much so that repair costs to the same extent as the one described may be more than getting a new induction cooker.
Furthermore, failure of the IGBT can be potentially dangerous for novices to handle.
Parasuraman S
December 15, 2015 at 11:26 pm
The cost of this service was just Rs.600 (About 9 US Dollars) and the new one might cost above Rs.2500 (About 39 US Dollars). So, for the customer, it was a bargain. Moreover, I always inform the customer about the estimate. Failure of IGBT is more or less similar to any component in high voltage power supplies, either primary or secondary. Yes, novices should be cautious, that is all. In an electronic servicing, there is always a risk factor, which is a part of the challenge. Anyhow thanks for your comments of concern.
indrajit
December 16, 2015 at 5:51 pm
Thanks for link
Bais bin Ahmad
December 20, 2015 at 10:21 pm
Repair induction cooker is very interesting. So far i have repaired more than 30 model of induction cookers made of china and european.
kaleem hashmi
July 20, 2017 at 12:59 am
pleas tell me where l can get books on induction cooker?
Parasuraman
July 29, 2017 at 6:59 pm
No idea. Pl check online.
Rohan
March 10, 2016 at 12:54 pm
Me too have same problem on Sanford induction cooker, which is give error massage is E1, Pl let me know how to fix this problem
Parasuraman S
March 13, 2016 at 11:31 pm
E1 error code differs from brand to brand. Generally it is due to malfunction of circuit, most probably on the power supply. Check ESRs of capacitor and check other active and passive components, preferably by removing them from the board. It is always a time consuming job.
Hilary
December 27, 2016 at 7:44 pm
I bought a 4 plate induction cooker from Guangzhou China but unfortunately it doesn't have a brand name. The plates started developing faults one after another although the fault seems to be the same on each coil circuit. The problem is that when it is switched on, it would work for a few minutes, then it would stop working though the panel will show that it is working. If you move the utensil to another plate, it will also work for a few minutes then stop working until after maybe 10 minutes. Am an electrician from Zambia though am not experienced in electronics, what could be the problem that has caused this failure?
Parasuraman
July 29, 2017 at 7:07 pm
There are two reasons mainly. 1) The temperature control sensor under the IGBT may be defective or IGBT itself. 2) The same type of sensor under the hot plate should also be replaced.
kaleem hashmi
July 20, 2017 at 1:04 am
very usefull information forr me and i want to become a member