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Rice cooker tripping breaker when switched on - Sanyo ECJ-JG10W(JP)240V

enricosanchez

Apr 20, 2021
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Hey, my trusty rice cooker from Japan has started instantly tripping the breakers when plugged in.

I pulled it apart and found that by disconnecting the heating element (circled in pink in photo below) I can power it up without tripping the breakers.
kcbfJO7.jpg


Here's a photo of the board:
EdHiQJo.jpg


And a close up of some suspicious brown marking around some diodes:
vhy0nFv.jpg


Any suggestions on a next step to isolate / repair the problem?
 

73's de Edd

Aug 21, 2015
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Sir enricosanchez . . . . .

by disconnecting the heating element (circled in pink in photo below)

but . . .BUT . . .BUT ! . . . . . thet unit don'ts gots itselfs no heeting element-ses-es-es . . . per se. Its using an induction heating design principle.
It utilizes the two sets of brownish orange enameled magnet wire coil bundles that your PINK terminals insulated buss wires tie into.
Expected to be driven with a post- ultrasonic - - - - -sub- LF RF drive from a pair of power IGBJT's that are hidden and heatsinked
by the nearby finned alum heatsink.
Need to get to them to use a meter to see if one or both of them are having dead shorted out Collector - Emitter's.

I suspicion that the trio of 51K film resistors on photo 3 are used in conjunction with a high quality teflon cap as a snubber circuit
and just extended time of use and their heating has caused the adjunct board discoloration.
I suspicion all three to be in series, but meter out in ohms mode for a possibility of parallel connections.
( You must eat GOBS and GOBS of Chinee lice ! )

OHMIGAWD ! ! ! . . . . I just hit ZOOM (
Click on this image to show the full image ) and the pic then got SO O O O damn LARGE, that I then had to turn around and look behind myself to see the whole picture in its entirity. !

Strange that the hefty spiral element pig tail fuse in photo 2 is still intact.
We also need to see under photo 2's filter board . . . two black release tabs . . . as most of the brain components of the unit seem to be on that board beneath.

Fill us in . . . . .

73's de Edd . . . . .

upload_2021-4-19_21-54-32.png

 
Last edited:

enricosanchez

Apr 20, 2021
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Apr 20, 2021
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Expected to be driven with a post- ultrasonic - - - - -sub- LF RF drive from a pair of power IGBJT's that are hidden and heatsinked by the nearby finned alum heatsink.
Need to get to them to use a meter to see if one or both of them are having dead shorted out Collector - Emitter's.

Thanks for the thoroughly entertaining reply. The rice cooker was a present for my wife about 10 years back, it cooks the rice under pressure and does a fantastic job (when it works).

I pulled off the filter board and heatsink and checked for continuity on the IGBTs. The one on the left is showing 1V for the end pins and 0.5V for end to middle pins. The one on the right is showing 0.0V for all connections. Could this be the culprit?
SrKmzTO.jpg


EDIT: yes the trio of 51K film resistors are in series as shown below:
lWAlrUj.jpg
 
Last edited:

Harald Kapp

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Nov 17, 2011
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Hey, my trusty rice cooker from Japan has started instantly tripping the breakers when plugged in.
Does it trip the breaker or the RCD? Together with @73's de Edd I wonder that the internal fuse should be o.k. when the external breaker trips.
If the RCD trips, it is probably not a matter of overcurrent but a lack in insulation causing excess fault current.
 

enricosanchez

Apr 20, 2021
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Thanks for the reply Harald, yes the soldered on fuse on the filter board (marked F11) is intact. The three switches on the left (below pic) are tripping as soon as the power is turned on to the unit. I believe these are breakers. Note that the power doesn't trip if the element is disconnected from the board.
huhrtf8.jpg


Measuring the resistance of the heating coil gives about 0.54 ohms, which I believe is within the correct range.
 
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73's de Edd

Aug 21, 2015
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Sir enricosanchez . . . . .

Thanks for the thoroughly entertaining reply.
I thoroughly believe in FUN in mine . . . and others lives . . . . . don't you ?


The one on the left is showing 1V for the end pins and 0.5V for end to middle pins.

Now that you have given me a viewing, that left item is actually being a Full Wave Bridge rectifier block, its being used for converting AC to DC voltage .

The one on the left is showing 1V for the end pins and 0.5V for end to middle pins.
That seems O.K.

The one on the right is showing 0.0V for all connections.

Looks like your unit is only using one POWER IGBT transistor

Come in with a soldering iron with its tip oriented such that you do no harm to the two large BROWN capacitors in the proximity.
You can see that the E . . .emitter and C . . . collector show, their having good solder drop surround / imbeddings.
Not so . .for the gate . . . so use a rosin flux droplet and add solder to the far sides G . . . gate lead at the PCB., so as to make it as large as a B-B shot and add solder to the bottom E . . emitter lead to also enlarge its solder mass.
Now if youwill then individually heat up the Gate and Emitter BB's the conjunct enhanced heat flow into a lead should let you then slip in and use a mini flat blade screwdriver and rotate to lever each of the E and G leads up and totally out of the PCB. That leaves only the Collector in circuit.

Now you can do this further testing . . . .

But, instead of using a diode test mode with your metering, go to its ohms mode and place your meter leads tips together to see how that is being displayed on your meters readout.
Then do a meter test probing between all of the 3 terminal possibilities of the transistor and then Test, the same way again, with the probes polarities reversed.
If you are getting readings of that same "shorted" or a very low ohms reading . . . .der IGBT . .bin KAPUT !
If so, we need all of its part numbering on its opposite side.
Also, we need the part numbering on the suspected driver IC at the 5 o' clock position of the central round ferrite toroid.
If I . . . .ZOOM . . . . your last picture and then look behind me, I can see that it is sandwiched between ZD1 and R20.

While still in OHMS mode, test the ohmmic value being read on the TH2 just above that same ferrite toroid.

THAAAAAAAAASSSSIT . . . . . . . fer now

AN INCURRED ADDENDA . . . .

You say . . . . .
Measuring the resistance of the heating coil *** gives about 0.54 ohms, which I believe is within the correct range.
*** That is being a set of inductive coils that induce VERY strong, ULTRA RAPIDLY changing magnetic fields into the cooking pot propers metallic structure and their resultant molecular friction is creating the units HEAT .

73's de Edd . . . . .

I just did a whole week's worth of cardio after my jumping around and violent arm thrashing upon walking into a spider web.
tenor.gif


.
 
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enricosanchez

Apr 20, 2021
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Thanks so much for the clear reply, I need to cook dinner (not rice) So I'll need to wait till tomorrow to pop the POWER IGBT transistor off and test further. Will reply then
 

enricosanchez

Apr 20, 2021
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Sir enricosanchez . . . . .
lever each of the E and G leads up and totally out of the PCB. That leaves only the Collector in circuit.

Now you can do this further testing . . . .

But, instead of using a diode test mode with your metering, go to its ohms mode and place your meter leads tips together to see how that is being displayed on your meters readout.
Then do a meter test probing between all of the 3 terminal possibilities of the transistor and then Test, the same way again, with the probes polarities reversed.
If you are getting readings of that same "shorted" or a very low ohms reading . . . .der IGBT . .bin KAPUT !
If so, we need all of its part numbering on its opposite side.
Also, we need the part numbering on the suspected driver IC at the 5 o' clock position of the central round ferrite toroid.
If I . . . .ZOOM . . . . your last picture and then look behind me, I can see that it is sandwiched between ZD1 and R20.

While still in OHMS mode, test the ohmmic value being read on the TH2 just above that same ferrite toroid.
.

Ok I lifted the E & G leads up and tested in ohms mode:

METER + TO METER - = 0.13 to 0.20

-E --> +C = 0.25
-E --> +G = 2.85
-C --> +G = 2.90
+E --> -C = 0.15
+E --> -G = 2.85
+C --> -G = 2.85

TH2 = 16.65 KΩ

Below is one of my oversized photos of the part number in question, looks like TOSHIBA 014KC TAB316ASG https://www.yoycart.com/Product/576317287199/
STT69tW.jpg
 
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