Zojirushi Rice Cooker NP-HMH10 Internal Battery Replacement

Written By: Sirui Wu

Comments: 17

Zojirushi Rice Cooker NP-HMH10 Internal Battery Replacement

Difficulty

Difficult

Steps

Time Required

45 minutes

Introduction

This guide walks through the disassembling of a Zojirushi Rice Cooker NP-HMH10 and replacing the internal battery.

If the front panel screen of a Zojirushi Rice Cooker does not show information, most likely the internal battery of the rice cooker is dead (except damage caused by human factors).

In this guide, the soldering iron is necessary, and be sure you have a basic knowledge of soldering or use the tool under the supervision of a person who has experience.

For safety reasons, unplug the device before you begin.

Tools

Parts

CR2450

Step 1

Flip the device over and remove the four screws on the base using the Phillips #0 screwdriver.

I have the hex security screw. Where can I get that tool?

Michael Hoy -

My Zojirushi comes with the Hex security screw. Where can I get that tool?

Michael Hoy -

Hi, you can find these hex screwdrivers on any big online shopping website like amazon. Make sure you measure the screw size before your buying, the screw size may differ base on your product.

Sirui Wu -

Hi Michael, we don't sell individual Hex security screwdrivers but if you're interested in buying a toolkit, our Manta toolkit includes various Hex security bits and Hex security SAE bits. There is an assortment of 112 steel bits in total with 2 drivers included too. Thanks!

Sarah Westberg -

It might be relevant to mention that the battery has the solder tabs welded onto them, so you will need to have a new one with these pre-welded to keep things simple.

registration -

These instructions also work for the HB618, with a few slight modifications. I added comments where appropriate.

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Step 2

Be aware, one of the four screws is a security Torx screw.
Using a Torx T9 screwdriver remove one screw from the bottom of the rice cooker.

Step 3

Gently lift the base from the device.
Be aware, DO NOT damage the cables that connect the base part and device.

For the HBC18 you may want to disconnect the while clip connecting cables coming from the front, and going to the little board at the back. This allows complete removal of the bottom.

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Step 4

Remove the five screws connecting the heatsink to the device.

Step 5

Remove the screws that connect the thick black and orange cables to the heat sink.

The heatsink cables do not exist for the HBC18, but undo the copper wiring from a little black tab in between the white housing and the pot coils.

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Step 6

Gently unplug the white-head pins with red and white cables on the other side.

Pull up on the flat cable connectors on the upper circuit board and disconnect all connectors.

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Step 7

Now switch to the fan of the heatsink. Using a tweezer carefully lift the four clips around the fan.
Pull out the fan.

For HBC18 pul out fan and moe to the left of the machine hang it down the front (still attached to lower circuit board).

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Step 8

After removing the fan now you can take out the whole heatsink and access the below part.
Be careful about the cables that are still connected to the heatsink.

For HBC18 you want to disconnect all cables and untangle them first. Take a picture if you need to remember where everything goes. After that gently lift up the white plastic contraption that holds the upper circuit board etc. Rotate it out of the way.

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Step 9

Above the PCB (Printed Circuit Board) is an isolated-plate. Take it away and unscrew the PCB below it.
Now you can have the access to the battery.

HBC18 does not have the cover plate. Just unscrew the two screws lift up the PCB, disconnect remaining connecters so you can work on the PCB separately. This PCB is otherwise identical to what is described here, so no more HBC18 specific instructions.

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Step 10

Turn the PCB to the other side. Find the soldering point of the battery as in the picture.

Step 11

Desolder the two tabs then unplug the old battery.

Step 12

Take out the new battery. Install it onto the PCB and solder it.
When you install the battery, be sure to put the positive and negative tabs into the right hole.

Step 13

After soldering, you can check your result by making sure the front screen is displayed properly.

Step 14

To reassemble your device, follow these instructions in reverse order.
Set the device to the correct time and save the setting. If the time is displayed properly, then congrats, you have successfully completed the replacement of the rice cookers battery! Go to make a delicious rice bowl to reward yourself.

Conclusion

To reassemble your device, follow these instructions in reverse order.

Author

Sirui Wu

Member since: 09/01/21

277 Reputation

5 comments

Thank you! It’s a shame the machine was designed without easy servicing for the battery. Otherwise a great rice cooker!

Paul Sharpe -

do you fix rice cook

TIM IE -

Nice repair. Thanks for sharing.

It looks as if you could replace the battery without doing any soldering. Once you break the yellow plastic surrounding the battery, can't you simply slide the battery out of the metal holder and slide in a new one?

gordonhamachi -

That’s not a holder. It comes from Panasonic with the two leads welded on and the yellow wrap is just there to keep those welds from seeing mechanical stress during shipping of the device it’s soldered into. If you pry the battery out, it’ll just break those spot-welds and won’t hold a new battery. Bottom line: It’s not designed to be user serviceable. It’s a PCB-mounted, soldered-on battery type. Someone on youtube suggested replacing it with a coin cell holder for a different battery size, but to each their own. I’ll probably replace mine with a genuine part from Mouser or Digikey. It’d be nice to use the delay cooking function again without having to set the clock first each time. It definitely is annoying that they expect customers to go to a service center for this. We hardly even have any electronics component stores in the USA anymore.

Note- I have a different model and it has a different battery. Don’t assume these instructions will translate to a different model. But thank you is due to Sirui Wu for sharing these.

Ryan Lewis - 17/05/23

Good Morning, when you had the rice cooker apart did you happen to notice if there might be a 120v tap on the power supply? The rice cookers from japan are much less expensive but only come in 100v 50/60hz

Navy Retired -