Question CPU/Mobo Using Windows Tablet without battery and screen, like SBC or CPU... Help

Skyh3ck

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Hello I had this Unbranded UB15MS10 Windows tablet for long time, purchased from one member here., it worked for few months and later screen broke.

The good thing is only the screen is gone, but when i connect the Tablet with HDMI monitor or TV, it is working fine.

Now i want to use this tablet or its motherboard just like SBC or standalone CPU. Specification of the tablet is as follows

https://www.bestbuy.com/site/unbranded-10-1-tablet-32gb-gray/9496117.p?skuId=9496117&intl=nosplash
Intel Atom Z 3000 category processor, 2 GB RAM, 32 Storage, Wifi and Bluetooth, 1 Micro HDMI, 1 Micro USB to charge and connect device

It has everything inbuilt to run as a low end or media center or experiement pc..

now, my problem is that i can not use the Charger and usb OTG at the same time, so if i want to use it as a cpu, it should get power from somwehre else other than micro usb.
i am thinking to remove the battery and make something that can power the device from battery connnector on motherboard and use the micro usb to connect usb hub.

here is the pic of motherboard. the battery has 3 cable, Red, Black and White. and the battery states it has 3.7 volt charge, i have never done this before just wanted to know guidance and help here. it s DIY project to make a useful pc out of broken tablet.

please check the images, if my problem is solved, then i will get a box prepared for this.

  1. can i just cut open any micro usb cable and connect the cable on the battery connector on motherboard, do i need kind of cirtuit or battery regulator in between
  2. is there any way i can expand the current single micro usb to few more by addition or soldering any more card or expansion
please suggest



 

Eximo

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I would not be surprised if a 5V input would be perfectly acceptable, would be odd to have a regulated power system that didn't accept a fairly wide range of inputs, probably up to 6 or 9v. Not sure what the white wire does in this case, could be a safety sensor. I would get a multimeter and see if it is grounded or something. Maybe a logic analyzer to see if it is pulsing a signal.

Probably test points somewhere on the board that do act as direct inputs for power as well. Might be possible to locate them if the silk screen is descriptive enough.

Worst case it pops, but not like you couldn't buy another really cheap tablet or NUC to do this with.

Still have my Lenovo IdeaStick, basically the same specs you listed, and it is just an oversized thumb drive with a teeny fan and WiFi.
 
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Skyh3ck

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Thanks..

The problem is that now devices had a single usb port either charge or use otg..

Both charge and org does not work at same time..


So I want to remove the battery completely and send power from those connectors and keep the usb free for org..
 

Eximo

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Powered USB hub would probably take care of this as well. But again, I think you could provide power in place of the battery without too much trouble. Just depends on how sophisticated it is. Might see 5V as an overvolt condition and refuse to start, that could very well be what that white wire is. A large value resistor is often connected to battery cells so that the voltage can be read with a very minor current flow. So possibly getting a 3.7 volt output into there would trick it.

That would be something to check with a multimeter with the battery attached.
 

Skyh3ck

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I think all battery have in built circuit..

Can I remove that circuit and connect + and - there.. will that circuit adjust the voltage
 

Eximo

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I think all battery have in built circuit..

Can I remove that circuit and connect + and - there.. will that circuit adjust the voltage
Batteries have a built in monitoring circuit that communicates with the system to control the charging. They do not carry the voltage converter, that is in the laptop.

Yes, I think that a direct 5V input has a good chance of working. I can't guarantee it, but most voltage regulators have a wider operation range than gets used.
 

Eximo

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Typically you don't repurpose standard connectors with an expected voltage with anything else, so my guess would no. No one would make a variable supply with USB outputs, that is just asking for trouble.

Buck converters are to take a high voltage down to a low voltage. Boost would be the opposite. Seems like they are suggesting it is a buck/boost converter though. 15W output. However, if your plan is to output something like 3.7 volts, probably not ideal, you should just go back to a battery at that point, and charge the battery with a lithium charger directly connected.

Personally I would still just try 5V and see what happens.
 

Skyh3ck

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Typically you don't repurpose standard connectors with an expected voltage with anything else, so my guess would no. No one would make a variable supply with USB outputs, that is just asking for trouble.

Buck converters are to take a high voltage down to a low voltage. Boost would be the opposite. Seems like they are suggesting it is a buck/boost converter though. 15W output. However, if your plan is to output something like 3.7 volts, probably not ideal, you should just go back to a battery at that point, and charge the battery with a lithium charger directly connected.

Personally I would still just try 5V and see what happens.
By try 5v you means .... Cut the usb cable and connect red and black cable directly to motherboard right?? But will it damage the motherboard...
 

Eximo

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Not sure how many different ways I can say the exact same thing.

We know the system charges through USB. USB is 5V. To charge a battery you have to have a little voltage over the voltage of the battery (voltage = pressure). They are taking 5V, probably down to 4.2 volts and using that to charge it. Generally, voltage regulators are designed to operate in a wide range so that the part is more appealing to various purposes. My guess would be the circuit taking the battery voltage and boosting it up to 5V (or more) is capable of taking 5V as an input with little problems.

Worst case it blows up, might have an over voltage circuit that thinks the battery is about to explode so won't turn on, or it will just work.

Or you can just hook the battery back up, get a lithium cell charging circuit (which are extremely, extremely common) and hook that to the battery directly. Battery will get charged and you would still have your USB port.

You had also asked about multiple USB ports, a powered USB hub would probably do the job.
 

Skyh3ck

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Or you can just hook the battery back up, get a lithium cell charging circuit (which are extremely, extremely common) and hook that to the battery directly. Battery will get charged and you would still have your USB port.

yes, that is what i was about to ask

without removing battery, i can just add TP4056 battery charger module

this one


so that i will always have a dedicated port to keep battery charge and make one microusb free,

now my concern is that the TP4056 is 1A max, can i connect 2A charger, will it harm the system
 

Skyh3ck

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So this is a big hurdle...

I want to keep the power connected to the motherboard just like any normal desktop computer...

Is there any way

1 ). I keep the battery connected and also connect to power.. so it dan charge and provide power at same time...

2) I remove the battery and and provide direct to motherboard.. from where battery was connected..

Any idea how can I achiev one of this
 

Skyh3ck

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Ok so I removed the battery and connected the LM2596 module buck converter to the motherboard..

I get 3.7v to the module and motherboard.. but tablet is not starting up.. the red LED is blinking in tab.. which means Tablet is indicating a low battery level...

Is there any way I can fool tablet to think battery is connected..
 

Eximo

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You could just connect the battery. It would take some measurement of the incoming signal from the battery to see if it is a simple analog indicator the battery is present, or a digital handshake.
 

Skyh3ck

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I want to use tablet without battery.. hence I connected 2596 buck converter module..


Cam capacitor or resistor play any role here
 

Eximo

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I understand, but to figure out what the battery does to the circuit that senses there is a battery, plug it back in. Take measurements.

I can't really speculate on what you might need. A low value resistor and and a relatively high capacity capacitor might make a decent 'battery' and trick the circuit. But only if it is a passive analog circuit. Doesn't sound like it is just a passive temperature sensor or anything like that.

If there is a digital circuit in the battery cell that was sending an all good back to the charging controller, then that is another matter entirely.
 

Skyh3ck

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I understand, but to figure out what the battery does to the circuit that senses there is a battery, plug it back in. Take measurements.

I can't really speculate on what you might need. A low value resistor and and a relatively high capacity capacitor might make a decent 'battery' and trick the circuit. But only if it is a passive analog circuit. Doesn't sound like it is just a passive temperature sensor or anything like that.

If there is a digital circuit in the battery cell that was sending an all good back to the charging controller, then that is another matter entirely.

Yes ... There is one circuit in the battery.. it's visible from the transparent cover...

What if I remove that and use it.. just the circuit and send power to that circuit...

But again... If it fails can I connect the circuit back again
 

Skyh3ck

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ok, so removed the circuit from the battery and it look like this one



i tried several other ways, like connecting the charger output directly to the motherboard, positive and negative, but no sucess

then i tried a 10k resistor and 10k thermistor and connected negative and white , ..

see

here i connected 10k resistor



i tried with 10k thermistor



then i connected the circuit back to its original connection but wihout the battery and sent power from charge to positive and negative on circuit



i tried the buck converter also,

but its maximum output i could increase to 4.3 volt only becuae it was connected to 5V charger



what else i can try

i think i will change the power cable

using a buck converter with 5V charger is limiting the output to 4.39V max

i am thinking to connect 5V directly from the charger with a new thick cable ?

any suggestion
 

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