Name that component: Magnetic hall lid sensor on Travelmate Spin B3 TMB311R-31

BrokenMagneticSensor

I have a Travelmate Spin B3 TMB311R-31 with a broken lid sensor and am trying to find a replacement part.

The laptop is out of warranty, so I'm out of luck with Acer. I can fix it myself if I could just get a replacement part, but I don't know what this sensor is.

The only markings on it are "TH" and "0b". I'm not sure if that's a zero or O, and I think that's a lower-case b and not a 6.

It's a 1.5mm x 1.5mm XDFN 6-pin package.

I've searched digikey, mouser, octopart, and google but I can't find it.

There's some pictures of the sensor here. It's right between the power plug and HDMI on the bottom of the board:

https://imgur.com/a/8JtOhT3

Sharanji

@BrokenMagneticSensor

Is it the Hall Acceleration Sensor board? Can you please post an image of the full board?

JackE

Only one Hall sensor listed for screen position orientation sensing, not closed lid sensing. Mounted on a board part no. 55.VMXN8.002. Called the Tablet Hall Acceleration sensor Board or Tablet Hall Orientation Board (probably THOb).

If a closed lid Hall sensor, then I suggest that you actually send the image of the discrete part to mouser or digikey customer or technical service to see if any one can identifiy the Hall sensor chip

billsey

Yes, likely much easier to just get the board using the part number as referenced above.

BrokenMagneticSensor

Yes, this is a component on the motherboard that detects the lid open/close state. It has nothing to do with the orientation sensor in the screen assembly.

I have searched everywhere on Google and the typical component vendors including Mouser and Digikey without success so far. I have put in sales inquires but have not yet heard back.

Next I will contact some of the listed Acer service centers in my area and see if I can buy the part off of one of them. I am sure someone has a BOM/component list for repairs.

BrokenMagneticSensor

Ha I go to this link:  https://community.acer.com/en/kb/articles/585-out-of-warranty-support-options

The "Acer Repair" link that goes to customercare.acer.com doesn't work because that website doesn't exist.

Nice.

JackE

Hold on. This same board and part no. may also be used as orientation sensor in other models that can also be used tablet mode. So it's not just for lid sensing. If you're trying to get to an ACER service center in your region, click this link. Choose your country or region. Click support link at top of country page. Follow screens to contact a service center nearest to you.

billsey

I see what component you mean, and boy is it a small one. Are you sure that's a hall sensor? I don't have access to schematics but I would have expected something to do with either the power input or less likely the HDMI output...

BrokenMagneticSensor

JackE said:

This same board and part no. may also be used as orientation sensor in other models that can also be used tablet mode.

That's a good idea but I've not found anything else using it, yet. The Travelmate B3 (Both Flip and non-flip) were made in 2020-present. The previous Travelmate model uses a different sensor. Unfortunately I don't have access to another other recent Acer laptops, BOMs, or schematics.

I got a reply from Digikey saying they had no idea what the part was, so no help there. Still waiting on Mouser.

BrokenMagneticSensor

billsey said:

I see what component you mean, and boy is it a small one. Are you sure that's a hall sensor? I don't have access to schematics but I would have expected something to do with either the power input or less likely the HDMI output...

They may have put it between the HDMI and power jack on purpose for magnetic shielding.

This ebay auction has pictures of the motherboard for the Travelmate B3.  https://www.ebay.com/itm/304227621493

You can see it on the second picture, lower right corner, between the ports. The magnet in the screen assembly lines up perfectly.

And yes, that's the component. I waved a magnet over it and it triggered. The problem with my sensor is that it goes latch-closed but never latch-open until power is removed.

JackE

OK. If you're referring to this chip, then yes it doesn't seem to be on a separate tablet hall orientation board, But it may indeed by the same hall chip on the mainboard. This would likely be identified on a full mainboard schematic which are usually available from 3rd party sources like this link for about $20usd. These schematics are usually not available from Acer that anyone on these forums has access to.

However, if it was mine, the issue is more of an annoyance than a serious disabling problem. Accordingly, for me, It would not be worth the risk of doing more serious collateral damage by trying  to replace what appears to be a very small surface mount.

BrokenMagneticSensor

New info.

I was skeptical but checked anyway. The in-screen board (Acer Part # 55.VMXN8.002) does have the same sensor on it. This board only exists in the Travelmate B3 Flip and it must be the switch to disable the touchpad and keyboard when the tablet is fully flipped into tablet mode. There is a small magnet in the plastic body bottom panel to trigger it. This magnet exists on the non-flip TMB311-31 models as well, even though there is no sensor for it.

I have a TMB311-31 in addition to my broken TMB311R-31, so I decided to look at it's sensor. In total, the three sensors are labeled "TH" and then "0b", "0x", and "0k." The 0 is probably for year 2020, and the lower letter is probably week or batch.

I suspect this is a TE Connectivity part, but it's not listed in their catalog. I'm going to email them and ask if they can ID it.

Worst case scenario is I guess I could scavenge a sensor off of a replacement 55.VMXN8.002 board, but that's the dumb and expensive way to do it.

JackE

Good luck with whatever you decide to do or not do.

BrokenMagneticSensor

I still can't figure out who makes this chip. I have searched and searched and searched. Both Digikey and Mouser said they had no idea.

I pulled out my multimeter today and set up the motherboard so I could test logic levels while triggering the sensor.

Pinout, top-view

    6 5 4

     T H

     0 b

    1 2 3

I don't see anything happening on pins 1, 3, or 5. Probably not-connected.

Pin 2 is ground.

Pin 4 is power-in 3.3v.

Pin 6 is output. Normally 3.3v when open and drops to 0.9V on magnetic trigger. It never comes back up when the magnetic field is removed, like it should.

I found some similar sensors that might work as a drop-in replacement. However, these are only pin-compatible. I'm not sure about their field sensitivity or other factors that might cause compatibility problems.

Magntek MT8691DT-1616

Murata Crocus CT100LW-ID6-M and CT100LW-HD6-M

Anpec Elec APX9136QFI-TRG

Orient-Chip OCH178VAD

Octopart and Findchips didn't know about most of these. I only found them through some hard-core googling. It doesn't help that different manufactures measure them at 1.5mm or 1.6mm and each seems to have their own declaration for the name of the package.

Digikey and Newark has the Murata Crocus chips for about $5 each.

JackE

>>>Worst case scenario is I guess I could scavenge a sensor off of a replacement 55.VMXN8.002 board, but that's the dumb and expensive way to do it.>>>

>>>I found some similar sensors that might work as a drop-in replacement. However, these are only pin-compatible. I'm not sure about their field sensitivity or other factors that might cause compatibility problems.>>>Magntek MT8691DT-1616. Murata Crocus CT100LW-ID6-M and CT100LW-HD6-M Anpec Elec APX9136QFI-TRG Orient-Chip OCH178VAD>>>

Well, let's see. The worst case costs about $35. So as long as you don't spend over that amount trying these other switches, I guess it'd be OK. However, the fun and learning experience you'd get by trying them all out might be worth more than doing it the dumb way. Don't you think? 

billsey

Well, actually worst case is a bricked laptop that requires a new MB to resurrect... Luckily if you are careful that's not a high probability.

StevenGen

BrokenMagneticSensor said:

I have a Travelmate Spin B3 TMB311R-31 with a broken lid sensor and am trying to find a replacement part.

The laptop is out of warranty, so I'm out of luck with Acer. I can fix it myself if I could just get a replacement part, but I don't know what this sensor is.

The only markings on it are "TH" and "0b". I'm not sure if that's a zero or O, and I think that's a lower-case b and not a 6.

It's a 1.5mm x 1.5mm XDFN 6-pin package.

I've searched digikey, mouser, octopart, and google but I can't find it.

There's some pictures of the sensor here. It's right between the power plug and HDMI on the bottom of the board:

https://imgur.com/a/8JtOhT3

What is the exact and full Spin model number that you have? It should be something like "TravelMate Spin B311R-31 — NX.VN0EK.001 or 002 or 007 or 00D". As for example and in the "TravelMate Spin B311R-31 — NX.VN0EK.002" model its got a  "HALL ACCELERATION SENSOR BOAR Acer PN:55.VMXN8.002 or ODM PN: HQ3160A E41000 which is a lid sensor and it looks like this as and also you can look up how these Hall Sensors work and pin point where this part fits into the laptop.

billsey

Steven, we pretty much have decided there are three sensors, the one you show is the one that measures if the opening has gone past 180°, the one in question checks to see if the lid has been opened at all, and the G-sensor checks for rotation.

BrokenMagneticSensor

I successfully transplanted the tablet-mode sensor from the display module to the motherboard over the weekend. I've lost tablet-mode functionality (automatic screen rotation and disabling of the touchpad and keyboard when the device is fully flipped), but at least the system doesn't die when I shut the lid to sleep anymore.

Getting the sensor off of the small display module was easy. Getting the old broken sensor off the motherboard was a huge pain. I'm just a hobbiest so I don't have a few of the tools I needed to do this right. My rework heat gun is one of those cheap $40 Chinese models and it's not the best, but also I don't have a hot plate. Getting the solder to flow when the board was sinking so much heat was difficult, and I didn't want to burn the nearby ports. Kapton tape and foil saved the ports and they look fine, but I had to hold that rework wand at max temp/flow, very close, for a long time. I was worried I would crack a joint or burn the board, but it looks fine and works great now.

Installing the transplant sensor onto the motherboard was also a pain. I had to do it twice because the first time only the center ground pad fused. Getting the three pads to ball while getting the center pad flat took some creative work. Good mask paste would have helped here but I didn't have the right stuff for this. Trying to flow solder in from the sides would have been easy but it just never worked.

Note the Crocus CT100LW-ID6-M and CT100LW-HD6-M sensors I mentioned above are actually linear sensors, not switches, so ignore everything I said about them.

I'll probably never figure out what that sensor is. Instead I'll have to bodge in some equivalent.

SOT553 and 563 packages have almost the exact same land grid dimensions as the 1.6mm x 1.6mm DFN6, and there's a number of manufacturers who make magnetic switches in that size, so I'm hoping maybe I can find one of those.

I will probably be a few weeks before I get back to this. I'm doing this purely for the "fun". Fixing this laptop was totally not worth my time.

JackE

>>>I'm doing this purely for the "fun". Fixing this laptop was totally not worth my time.>>>

Does this mean you've already spent more than $35 too?

BrokenMagneticSensor

I successfully replaced the magnetic switch sensor in my tablet-mode board. By "tablet-mode board" I mean the 55.VMXN8.002 part inside the screen assembly.

In the case of the lid switch sensor on the motherboard, it would be fairly easy to bodge in lots of different package sizes, including the very common SOT23 or maybe even a SIP. You just need to scratch the board leads to expose some copper and put in whatever you want. The problem is finding something with similar magnetic specifications. Like I said before, I scavenged the sensor in my tablet-mode board, but in hindsight I would have left it where it was.

In the case of the tablet-mode board, there's limited options to bodge in a part that isn't a DFN1616 chip because there isn't much space on the board to put anything else. Fortunately SOT553 and SOT563 packages fit nicely and there's a number of different sensors available in that package size.

The problem with replacements is that we don't know the specifications of the original, so I had to guess.

Ultimately I replaced my sensor with a Diodes AH1883-ZG-7. I was a little worried that the ground pad in the center of the board might intersect with the longer pads on the SOT553 but that wasn't a problem. You can always lacquer the pad too.

The only issue is that I've noticed that when the laptop's screen is at 180 degrees the switch tends to bounce on and off. A few degrees in either direction stops the bouncing but I don't know if this is normal or not since I never really tested it with the original sensor. Maybe a less sensitive sensor or one with different parameters wouldn't do that.

Ideally I would have gone with a Diodes AH1806-Z-7, AH1808-Z-7, or maybe AH1807-Z-7, but nobody had stock anywhere. Diodes AH1883-ZG-7 is what I went with as a first try and the older AH180N-ZG-7 would also work (might have even been better). Memsic MHA182AS-S and Rohm BU52021HFV-TR are other possible options that might work.

If I was to do it over again I might try a Memsic MHA182AS-S and then Diodes AH1806-Z-7.