What is this board inside my all in one computer for?

[Lis_182_evo]

Hi! I found a board in my all-in-one computer that receives power, and that's it. The board is not connected to any other components. What could this be and what role does it serve?

[Lis_182_evo]

Photo

[pcprogrammer]

How and where was it mounted in your all in one computer.

It looks like there is some LED on the bottom of the board and it might transmit some data via that?

[Lis_182_evo]

The board is inside the all-in-one

[pcprogrammer]

It is a mystery.

You might want to change the title of the thread to get more response to it.

Something like "What is this board inside my all in one computer for?" makes more sense.

[Psi]

Very odd, my only thought, other than something dodgy, was some sort of electronic asset tag.

So they can be tracked for inventory and information like S/N can be extracted without the PC needing power.

It looks to have a IR Tx and Rx led.

[pcprogrammer]

Yeah maybe, but the mounting does not show if it is possible to probe it from the outside and with the lid open, like on the photo, the possible IR transceiver is not visible.

[Whales]

Quite a mystery.

I also thought an asset tag, but then why the 360R resistor in a really big package over a milled slot?  And it's being watched by a LED-phototransistor thing (TCRT1000) from the other side of the board?  Huh?

I assume the 8-pin SOIC is a microcontroller.  It would be nice to see the part number (tip: clear sticky tape on top sometimes helps, as does using a torch at a very shallow angle to the surface).

Lis_182 please open the grey box with one hole and tell us what's inside it.  Assuming you don't mind damaging this thing.

[Chalcogenide]

TRCT1000 is a reflective optical sensor, and the other components seem like a buzzer, a dual color(?) LED, an MCU and a buzzer. I don't see any RF stuff, honestly. Is the battery empty?

[Whales]

I'd agree on the bi-colour LED, but not 100% on the buzzer.  It could be a gas sensor?  But I guess those tend to have more than 2 terminals.

Is it just me, or does one of the traces from the battery go to a missing resistor?  I wonder if there is another trace from the battery connector or if the whole thing has never done anything   Someone installed these in computers as a troll.

[pcprogrammer]

More close up pictures of the board would help.

Also a shot of the computer with the board removed, and indeed the lid removed of the box next to where the mystery board is placed can be of help.

[Lis_182_evo]

TRCT1000 is a reflective optical sensor, and the other components seem like a buzzer, a dual color(?) LED, an MCU and a buzzer. I don't see any RF stuff, honestly. Is the battery empty?

Yes, the power element is charged. The LED is two-colored: red and green. For example: When I connect the power, the LED first lights up red (once), then green, and then it turns off. A couple of times, when I repeat the operation (disconnecting and reconnecting the power), it lit up: Once red, 2-3 times green, or red-green-red-green-red-green.

[pcprogrammer]

Someone installed these in computers as a troll.

Bit of an expensive prank, if done in a large batch of these computers.

@Lis_182_evo, what is the make and model of this all in one computer?

[Lis_182_evo]

Quite a mystery.

I also thought an asset tag, but then why the 360R resistor in a really big package over a milled slot?  And it's being watched by a LED-phototransistor thing (TCRT1000) from the other side of the board?  Huh?

I assume the 8-pin SOIC is a microcontroller.  It would be nice to see the part number (tip: clear sticky tape on top sometimes helps, as does using a torch at a very shallow angle to the surface).

Lis_182 please open the grey box with one hole and tell us what's inside it.  Assuming you don't mind damaging this thing.

Yes, by the way, there is an inscription on the controller: atmelu t1ny 2222mue

[pcprogrammer]

I also thought an asset tag, but then why the 360R resistor in a really big package over a milled slot?  And it's being watched by a LED-phototransistor thing (TCRT1000) from the other side of the board?  Huh?

One of the holes of the TCRT1000 is blocked by this big resistor. Very odd indeed.

[pcprogrammer]

Yes, by the way, there is an inscription on the controller: atmelu t1ny 2222mue

That is an ATtiny 22 AVR based MCU. https://www.mcselec.com/atmelpdf/attiny22.pdf

[coppercone2]

 do you notice anything about the computer when its removed?

does it emit RF energy? Perhaps probe it with a shorted oscilloscope probe to see if you can catch a chirp or something

[Lis_182_evo]

do you notice anything about the computer when its removed?

does it emit RF energy? Perhaps probe it with a shorted oscilloscope probe to see if you can catch a chirp or something

It works as expected, because this board is not connected to other components in the PC.

I've disassembled many all-in-ones and laptops. This is the first time I've seen something like this.

[coppercone2]

Could it be a sensor to detect access for a warentee?

I think it would be prudent to figure out how to bypass such a sensor

[Psi]

I wonder if it's just optically counting something.
Like insert/removal of something, or syncing to day/night cycles to count number of days in service after removal from shipping box.

Could be very crudely trying to detect high levels of some types of radiation by means of two optical sensors one with a higher density object blocking it (that resistor) for signal comparison.   Maybe for warranty reasons to confirm laptop never went through those really high energy x-ray systems that sterilize mail and some facilities. 

What is the metal square thing that it's next to?

[SeanB]

Definitely a warranty tag, likely used during the warranty period to hold information, as it has a serial EEPROM attached, so you use an IR communicator to recover things like serial number, as built info, Windows key and other system serial numbers. Makes it easier during any warranty work to simply scan this off, and poopulate the repair order form, and then compare to the as built to see if there are any "unauthorised" upgrades, or if they need to replace any parts, or for reinstall with a new blank drive.

[MathWizard]

Isn't it a little battery, wrapped up in black plastic/rubber, and the chips would be a charging circuit ??

[coppercone2]

its pretty close to that speaker

[pcprogrammer]

Isn't it a little battery, wrapped up in black plastic/rubber, and the chips would be a charging circuit ??

Yes, the round thing is a battery, but the circuit has been identified as a MCU with an IR transceiver, so I doubt it being a charging circuit for that battery. There are no other connections to this small board.

its pretty close to that speaker

Yes and what is it that you are trying to say with that?

That it picks up the changing magnetic field of the speaker and charges the battery with that?

Even if the big black part is a coil, there is no additional circuitry to make it a safe charger.

[u666sa]

This appears to be one of the stolen ICL SafeRAY's Si105.Mi's. https://wiki.dno-it.ru/2023/04/26/sbornaya-informacziya-monoblok-icl-saferay-si105-mi/
No, this is not an asset tag, it's something else. But since it is stolen equipment....