Need help to identify failed component in rice cooker

[Per von Zweigbergk]

My rice cooker just failed.

It's given me many years of service, but now a component seems to have
suffered some kind of mechanical faliure. It's a rather standard model
with the typical Warm/Cook modes. The model, specifically is a Tanin
TR-2002A. (You won't find anything Googling for it, except maybe, in a
few days this Usenet post. ) Relevant data: AC 220 V, ~ 50 Hz 620 W.

The component was connected in series with one of the AC power inputs,
and measuring over the poles gives me 0 Ohm of resistance.

Could somebody please help me to identify the type of this component? I
suspect it may be a thermal fuse, but I'm not at all sure about the
values required. Then again, it might be something completely
different, and I'm not really sure about it.

A close-up image of the component can be found at
http://www.pvz.pp.se/stuff/riskokarkomponent.jpg (59.2 kB). The actual
size of the component is approximately 15 millimeters from end to end.

 

[Meat Plow]

My rice cooker just failed.

It's given me many years of service, but now a component seems to have
suffered some kind of mechanical faliure. It's a rather standard model
with the typical Warm/Cook modes. The model, specifically is a Tanin
TR-2002A. (You won't find anything Googling for it, except maybe, in a
few days this Usenet post. ) Relevant data: AC 220 V, ~ 50 Hz 620 W.

The component was connected in series with one of the AC power inputs,
and measuring over the poles gives me 0 Ohm of resistance.

Could somebody please help me to identify the type of this component? I
suspect it may be a thermal fuse, but I'm not at all sure about the
values required. Then again, it might be something completely
different, and I'm not really sure about it.

A close-up image of the component can be found at
http://www.pvz.pp.se/stuff/riskokarkomponent.jpg (59.2 kB). The actual
size of the component is approximately 15 millimeters from end to end.

Looks like it could be a fusible link.

 

[John Hudak]

My rice cooker just failed.

It's given me many years of service, but now a component seems to have
suffered some kind of mechanical faliure. It's a rather standard model
with the typical Warm/Cook modes. The model, specifically is a Tanin
TR-2002A. (You won't find anything Googling for it, except maybe, in a
few days this Usenet post. ) Relevant data: AC 220 V, ~ 50 Hz 620 W.

The component was connected in series with one of the AC power inputs,
and measuring over the poles gives me 0 Ohm of resistance.

Could somebody please help me to identify the type of this component? I
suspect it may be a thermal fuse, but I'm not at all sure about the
values required. Then again, it might be something completely different,
and I'm not really sure about it.

A close-up image of the component can be found at
http://www.pvz.pp.se/stuff/riskokarkomponent.jpg (59.2 kB). The actual
size of the component is approximately 15 millimeters from end to end.

This looks like it is a crimp connection from the heating element to the
screw terminals of the 120/220 VAC input. Failures of this type are
common in resistive heating elements. The high current that passes
through the point of failure causes local heating (due to bends, local
impurities,etc.) which eventually, over many uses, causes a break.

Repairs for this are almost non-existent. Depending on what the other
side of the connections looks like (e.g. the rest of the heating
element) you may be able to use a crimp-style ring tongue terminal and
crimp it onto the end of the existing heating element. This assumes
there is enough room to move the element so that the ring terminal can
attach to the mounting screw. I've seen hardware stores that carry ring
tongue terminals that can accommodate #6 AWG. Note: if your heating
element is a rod with a thick coating on it, and the coating is flaking
off, the element is bad and beyond repair. Also, if you try to bend the
rod to make it attach to the screw connection, you will most likely
cause cracks in the coating, and the element will be useless.

The short story is that you probably should start looking for another
cooker. I doubt that you will find any direct replacement for the
element, which is what really should be done. Good luck
J

 

[Michael Black]

The component was connected in series with one of the AC power inputs,
and measuring over the poles gives me 0 Ohm of resistance.

You need to get the terminology right.

"0 ohms" is a short. SOmething in that location with two terminals and
shorted is unlikely to affect operation. If it's really zero ohms, then
it will pass the current and everything will be fine.

If you actually mean "there's no ohms across it" then you really mean
it has near infinite resistance, ie an open circuit. If that's the
case, it's no wonder the rest of the thing doesn't work, it can't get
power since this open device is preventing any power to get to the
rest of the device.

On the other hand, even if it is open, chances are good it's not a
particularly special device, though it is there to protect the rest
of the circuit, either a fuse or something to limit current when things
get turned on initially. It won't work without something there, but
what it does is preventative.

If it really is open circuit, then you have to consider that it may
not be the fault, but a symptom. If it's opened up, it might just
have "worn out" but it may have "blown" because something else in
the unit is bad, causing this component to go with it. Until
you determine whether there is something else at fault, replacing
this component may merely mean it "blows" again.

On the other hand, it may be that simple, replacing it does fix
the problem.

Michael

 

[Per von Zweigbergk]

This looks like it is a crimp connection from the heating element to
the screw terminals of the 120/220 VAC input. Failures of this type
are common in resistive heating elements. The high current that passes
through the point of failure causes local heating (due to bends, local
impurities,etc.) which eventually, over many uses, causes a break.

Nope. That's not it.

There's a wire from the terminals of the 220 VAC input, going to a
screw terminal, passing through this component, and then going into the
rest of the appliance via a wire from another screw terminal. The
connection to the heating element is intact, however, the actual
component in the picture seems to be broken.

 

[Per von Zweigbergk]

You need to get the terminology right.

"0 ohms" is a short. SOmething in that location with two terminals and
shorted is unlikely to affect operation. If it's really zero ohms, then
it will pass the current and everything will be fine.

Yup. The component presents 0 ohms, a short, whatever. It'd pass
current if the ring terminal were still intact. However, the actual
component is physically damaged, which is why I want to replace it.

I probably could make the cooker functional (though probably not very
safe) by shorting over where that component used to be with moderately
thick wire. I haven't tried this yet though, and I don't want to try it
before I've identified the failed component.

 

[Per von Zweigbergk]

Looks like it could be a fusible link.

In that case, what would "170" mean? 6A probably means the component is
rated to pass 6 amps of current.

 

[James Beck]

In that case, what would "170" mean? 6A probably means the component is
rated to pass 6 amps of current.

It looks like a current or thermal fuse.
Could the 170 mean it opens at 170C ?
It is very common for appliances with heating elements in them to have a
thermal link/fuse.

Jim

 

[Meat Plow]

In that case, what would "170" mean? 6A probably means the component is
rated to pass 6 amps of current.

Temperature that it fails at in centigrade? That's a wild guess which is
all I have

 

[Per von Zweigbergk]

My rice cooker just failed.

It's given me many years of service, but now a component seems to have
suffered some kind of mechanical faliure. It's a rather standard model
with the typical Warm/Cook modes. The model, specifically is a Tanin
TR-2002A. (You won't find anything Googling for it, except maybe, in a
few days this Usenet post. ) Relevant data: AC 220 V, ~ 50 Hz 620 W.

The component was connected in series with one of the AC power inputs,
and measuring over the poles gives me 0 Ohm of resistance.

Could somebody please help me to identify the type of this component? I
suspect it may be a thermal fuse, but I'm not at all sure about the
values required. Then again, it might be something completely
different, and I'm not really sure about it.

A close-up image of the component can be found at
http://www.pvz.pp.se/stuff/riskokarkomponent.jpg (59.2 kB). The actual
size of the component is approximately 15 millimeters from end to end.

I thought it might be additionally helpful to take a picture of the
innards of the rice cooker, to illustrate where in the circuit the
mystery component was located.

It can be found at http://www.pvz.pp.se/stuff/ricecooker-innards.jpg

 

[msg]

Per von Zweigbergk wrote:


To me it looks like a terminal lug from the end of a thermal fuse
or thermostat.

I thought it might be additionally helpful to take a picture of the
innards of the rice cooker, to illustrate where in the circuit the
mystery component was located.

It can be found at http://www.pvz.pp.se/stuff/ricecooker-innards.jpg

What is the maximum rated temperature of the cooker? Knowing that, I
would install a cartridge-style thermal fuse or thermostat into that
ceramic block in series with the AC mains in the photograph with a
value about 20 degrees F higher than the max. rating of the cooker.
Inspect the method of thermal contact inside that block; it may be
useful to use refractory cement to make good contact between the
business end of that thermal block and the new thermal protection
device.

You could even salvage a thermostat from a drip-style coffee maker
which may be about the right temperature (these units are easily
found in the trash, rummage sales, etc. in the States).

Regards,

Michael

 

[Per von Zweigbergk]

What is the maximum rated temperature of the cooker? Knowing that, I
would install a cartridge-style thermal fuse or thermostat into that
ceramic block in series with the AC mains in the photograph with a
value about 20 degrees F higher than the max. rating of the cooker.
Inspect the method of thermal contact inside that block; it may be
useful to use refractory cement to make good contact between the
business end of that thermal block and the new thermal protection
device.

You could even salvage a thermostat from a drip-style coffee maker
which may be about the right temperature (these units are easily
found in the trash, rummage sales, etc. in the States).

Regards,

Michael

It's probably not the thermostat, since it had no direct contact with
the cooking area whatsoever, it was just suspended in the air between
those two terminals just right of the line input.

As i said, the component was really small, though the image makes it
look monstrous. Something like 2 centimeters from top to bottom (in the
image).

As for the thermostat, I think, though I'm not sure, that is the block
covered by the metal plate at the right of the image. It has two wires
going from it.

From what I've understood of the principle of operations of rice
cookers, they have two modes. Warm, and cook. Warm activates low power
heating, just enough to keep the rice at a comfortable serving
temperature. Cook sets the high power heater on. The thermostat trips
just above the boiling point of water. The theory being, that when the
water is all gone, the temperature will rise above boiling, and, so it's
time to turn off the cooker. (Rather genius in its simplicity.)

What I think might be happening, is that there is some kind of
electromagnet that keeps the cooker in cook mode as long as the
temperature is too low. When the temperatures reaches the cut-off-point,
I think current is cut off to the electromagnet, and the switch springs
back into the warm mode.

In light of the principle of operation I lined out, it makes no sense
for a thermostat, if that the mystery component was, to be in series
with the entire device. If that were the case, how would it ever enter
warm mode?

No, I must go with thermal fuse, if the component is thermal in nature
at all, which I simply don't know if it is right now.

 

[Per von Zweigbergk]

My rice cooker just failed.

It's given me many years of service, but now a component seems to have
suffered some kind of mechanical faliure. It's a rather standard model
with the typical Warm/Cook modes. The model, specifically is a Tanin
TR-2002A. (You won't find anything Googling for it, except maybe, in a
few days this Usenet post. ) Relevant data: AC 220 V, ~ 50 Hz 620 W.

The component was connected in series with one of the AC power inputs,
and measuring over the poles gives me 0 Ohm of resistance.

Could somebody please help me to identify the type of this component? I
suspect it may be a thermal fuse, but I'm not at all sure about the
values required. Then again, it might be something completely
different, and I'm not really sure about it.

A close-up image of the component can be found at
http://www.pvz.pp.se/stuff/riskokarkomponent.jpg (59.2 kB). The actual
size of the component is approximately 15 millimeters from end to end.

I was able to fix it. Working under the assumption that the failed
component was a thermal fuse, I figured there was no harm in shorting
together over the thermal fuse, except for a risk of overheating.

So, I shorted the fuse leads together, and the device appeared to
function normally, so I went out to Elfa and got myself a new thermal
fuse. Working from the assumption that "170" in fact was the maximum
temperature in Celcius, I replaced it with the closest value available,
184 degrees.

The rice cooker appears to be functional again. I even checked the
current draw, and it seems to be very close to spec.

They don't build these the way they used to any more. Definitely worth
the repair.

Thank you for your help.