Bose QuietComfort 35 PARTIAL Teardown

Geschrieben von: Junrei
Veröffentlicht: 02/11/18
  • Kommentare: 42

Bose QuietComfort 35 PARTIAL Teardown

Veröffentlicht: 02/11/18

Teardown

Einleitung

Difficulty: Medium

Partial teardown of Bose QuietComfort 35 wireless noise cancelling headphones.

Exposes all circuit boards and battery.

Does not disassemble head band, reveal access to speakers/drivers, or disassemble buttons.

  1. U6fLj3BLEQfrHNRA

    • Today my Bose headphones drained its battery about halfway in only about 1 hour. It used to last well over 15 hours. It was a sign that the battery was on its way out.

    • Officially, it costs $259 + $100 shipping to have Bose replace the battery. These headphones cost $300. Ridiculous. I couldn't find any batteries for this online and customer support said the battery is not user-replaceable.

    • This guide shows disassembly down to the battery.

    • Tools required: Thin bladed phillips screwdriver, plastic or wood spudger when handling battery, small flat blade screw driver. Micro-screwdrivers will work fine.

    • Beware of ESD (static electricity). When you open electronics not all parts will be protected from ESD. This can kill some/all of your device. Do not work on/over/near rugs and fuzzy things. Do not wear fuzzy clothes. Discharge yourself to a large metal object before working. Recommended: grounding mat and wrist strap. Can also work naked.

    • ESD: You can even work naked or almost naked to reduce risk of clothing ESD. I'm not kidding. Obviously do not remove clothing in public...

    not kidding about the naked part: https://forums.tomshardware.com/threads/...

    I first learned of this from the megatokyo web comic :D

    Junrei -

    ESD probably killed the microphone board of my headphones. So hence the warning.

    Junrei -

  2. 22BYBDDul4ZhSBMX
    22BYBDDul4ZhSBMX
    rKa3wHhqd3tBBpVe
    1usPmKJNHKQllUYJ

    • Lets start with the right side.

    • Dip your finger behind the foam muff and pull up to unsnap it.

    • Pull the foam cover off of the headphone to reveal screws and a compartment.

    right side: that’s where the power/bluetooth switch is

    Mischl -

    Yes thats right. Also it says R on the inside of the headphone. You can see it here.

    Junrei -

  3. 2lxTZsqjLEVB4iwB
    2lxTZsqjLEVB4iwB
    QBPJD1MwCEjblEWh
    aYBitfofxnGFoSW4

    • There are 3 screws holding the outer metal cover on.

    • This reveals the circuit board. Be careful not to lose the rubber around the mic.

    • Make sure you don't lose the power switch.

    • Ribbon cable safety: Don't shear side to side. Don't twist. If disconnecting disconnect it using a pry tool at the connector, never by pulling up on the cable!

    • THIS IS OPTIONAL. Only do this if you need to: If removing the ribbon cable, once this cable is disconnected you can gently pull up on it (not bending too sharply!) to detach the adhesive from the speaker chamber

    • 3rd picture shows prying upwards on the edge of the ribbon connector. It has some glue that must be pushed aside. It is weak so you can probably just pry up on the ribbon connector.

    Removing ribbon cable for exploration purposes caused me trouble down the road. I had not firmly reseated it when putting back together so the buttons and lights were dead. And now the buttons feel like they are only working intermittantly? Not sure if its my Mac preventing the buttons from working actually. Perhaps the glue securing the connector was there to prevent it coming loose (which might have happened at this point).

    Junrei -

    How big screwdriver?

    Nicolai Eliesen -

    I need to replace the speaker for Bose 35 as right side one is not having any sound. How to remove ribbon and cap above speaker safely.

    Raja -

  4. ZH1qsvrpWpUyVZ4C
    ZH1qsvrpWpUyVZ4C
    EgQFbVrUb1kOdNME

    • To remove the circuit boards you can remove the 4 short screws as shown.

    • For the top board you can pry around the edges (use plastic or wood tool). Note that there is a connector on the back that connects to a board inside the compartment on the other side.

    • The bottom board I recall was just loose. Beware of ruining the other ribbon connector (yellow) attached to it.

    • For the top board there is a speaker wire (yellow) going behind it that will keep this from being removed. It is thin so it could be broken easily.

  5. JXZqStfrXktM1HIA

    • FYI, headband connection can be disconnected by simply prying between the phone body and the band.

  6. yYqhHyuROVgkAt3c

    • On the other side, there is a compartment with a cover glued to it. The glue isn't terribly strong. You can stick a thin screwdriver in the notch shown to split it open.

    • Once opened the glue will not reseal properly most likely.

    • Inside is a circuit board and another mic, and the cable to the other side.

    • I did have some trouble opening this as I tried to push it open from the other side using the hole on the other side for the headband.

    What's that white part…I accidentally push it and it's bent down a little bit…is it gonna be a problem?…please help me

    Buvisuru Bandara -

  7. cyioIFULd4dX3nWC
    cyioIFULd4dX3nWC
    SsqBbfbLCNQsFHKL

    • Moving onto the left side, remove the cover and the foam pieces.

    • This side has only 2 screws holding the front cover on.

    • Here is the circuit for the left side.

  8. tAfVvEoi1pGfL5Ri

    • Flip it over

    • Here I stuck a screwdriver in the notch on the compartment cover. You have to use quite a bit of force to push the screwdriver in there.

    • Better to use a micro-screwdriver for this instead of what I did. It would probably slip in there easier.

    • Extreme caution should be taken during this step. Try not to suddenly push a metal screwdriver in there because the battery is right behind it. You don't want to puncture the battery.

  9. MpOTpwbtwVnaJnAP
    MpOTpwbtwVnaJnAP
    36SBfsEcHOobF4OG

    • The battery is revealed!

    • Use a WOODEN or PLASTIC tool to pry the battery free of its adhesive. It is not held in strongly. If you use METAL you may puncture the outer foil and compromise the battery.

  10. nLEdyP4lqwyAcFHc
    nLEdyP4lqwyAcFHc
    vKaN1FbPSQjbjWyh
    TNuALaylS2YfiWMQ

    • On the other side the battery is soldered to the board.

    • It is marked with T (temperature), B-, and B+.

    • The battery is a Synergy AHB110520CPS. An online search revealed nothing. I wonder if this is a proprietary battery only sold to Bose, or its just already obsolete (1.5 yrs old).

    • The battery specs are 495mAh 3.7V, 4.2V max (I think).

    • It is an Advanced Hybrid Battery, which is a very compact battery technology made by Synergy Taiwan.

    • Replace with a battery of similar specifications, and try to find one with similar internal resistance. I am not sure how to measure that for this battery but you may look it up online.

    Can you tell physical dimensions of the battery?

    Pasi Tolvanen -

    +1 on that :)

    Alex -

    You state that the battery is 1.5 yrs old. When I had a problem with my 2.5 year old QC35 headphones, I took them into the Bose store, described the issue, and the manager said, ‘That shouldn’t have happened’, and swapped my cans for a new set. Very simple and no cost to me. Not sure where the earlier-mentioned repair price of $259 + $100 would come into this. My experience was only of good customer service.

    davidswanson -

    That is what it shows on the website. I guess when you go to a store and have that in face interaction, they are a lot nicer.

    Rowdy Bedsaul -

  11. AXDaIGydGHj5QWYJ

    • Reassembly is the reverse of the disassembly

    • To reattach the foam muffs press the border into the frame of the headphone plastic using your fingernail (thumbnail preferably). It will snap in at various places.

Tinte & Feder

Junrei

Mitglied seit: 02/11/18

468 Reputation

30 Kommentare

A little help here. Will any old battery work regardless of its resistance? Resistance and voltage determines current. As long as the voltage is right I figure it doesn’t matter what the charging Amperes of the battery is. Is this correct or incorrect?

Junrei -

What is battery dimensions? Thank you.

Aca Miln -

I don’t have it with me right now but I think its 1.75” x 0.4” x 0.3” (inches). I couldn’t actually find a battery of the same shape anyways. I am going to try this battery: https://www.ebay.com/itm/3-7V-500-mAh-Po... and hope that it fits somehow.

Junrei -

Piece of cake! NOT! Thank you Junrei for your detailed breakdown of the QuiteComfort 35. Hopefully, by the time my lithuim battery wears out there will be a replacement battery, but I’m afraid I may not get it back together again successfully. Normally, if something no longer works I’ll dive in and see if I can fix it - nothing to lose. But, if - and when - a replacement battery is available the battery may cost too much to risk an unsuccessful reassembly.

Bulaien -

@bulaien I was more or less able to reassemble just fine. The glue on the battery compartment door is a little loose but it is mostly holding itself shut. With the ear muff over it I didn’t even notice anything the next day when I used it.

Junrei -

If anybody has success with finding a suitable battery replacement model please point to the battery model number.

It seems Bose does not want people to replace the battery and customers of Bose should just buy the newest Bose headphones. I don’t want to throw my headphone away, I just want a new battery….

No Name -

@No Name I did replace mine with this: https://www.ebay.com/itm/3-7V-500-mAh-Po... . I put mine behind the ear flap like so: https://imgur.com/m7fLX6F . The ear felt holds it in.

So far I do not know if it will charge, but it works. It did not overheat on the charger. Didn’t even get warm. Also my lights and volume/play controls/mic are not working. I did disconnect one of the ribbon connectors and maybe i messed up putting it back together. Otherwise it works fine.

Junrei -

Update: I have been using the replacement battery and charging it/discharging it just fine. It lasts a long time too. The reported battery level goes up and down just like the old one used to. Perfectly replaced.

Also I opened it up again and one of the ribbon cables I messed with was not really connected. I plugged it in and i got LIGHTS and volume controls (initially volume controls but its being flaky with me right now). Microphone still doesnt seem to work but it’s plugged in. I dunno why.

Junrei -

Hi Junrei, very good repair efforts and tips! I have a question. Does the replacement battery already has its own thermistor in the package or should it need to be placed near an existing thermistor where the old battery was once was? Thanks.

Ray

roju1645 -

re: battery resistance

True to some extend. There are several regions for battery charging:

preconditioning: the battery is too deeply discharged, it will be trickle charged at first

constant current: battery is charged with a constant current until fixed voltage is achieved (e.g. 4.2V) - here the battery resistance makes a big difference

constant voltage: battery is charged with constant voltage - this is slower and now has to make up for the lesser charge from previous process

trickle,maintain: maintenance

However, as you draw current from the battery (for the speakers), the voltage at the internal circuits will also drop due to I*R. Therefore, it looks as if the battery is much more discharged. In effect you cannot get below a certain internal voltage anymore. Due to the nonlinear nature of the Q/V curve, this can mean quite a lot of charge becomes inaccessible. Battery is effectively dead.

andregunther -

@andregunther i’m not sure what you mean. My original question was more or less “can i use any replacement battery regardless of internal resistance?” I didnt mean I was going to use an old battery.

Update: I have been using the replacement battery and charging it/discharging it just fine. It lasts a long time too. The reported battery level goes up and down just like the old one used to. Perfectly replaced.

Also I opened it up again and one of the ribbon cables I messed with was not really connected. I plugged it in and i got LIGHTS and volume controls (initially volume controls but its being flaky with me right now). Microphone still doesnt seem to work but it’s plugged in. I dunno why.

Junrei -

Hm, today the headphones suddenly powered down at 50% but I had been using it for like 2 days before that (16 hours).

Junrei -

Headphones still going strong, no problems.

I think I had killed the microphone board with ESD unfortunately. I was sitting on my fuzzy couch while doing the teardown. Some devices dont guarantee ESD protection once you open them. I knew better too…

Junrei -

Hello Junrei,

I was wondering if the battery https://www.ebay.com/itm/3-7V-500-mAh-Po... holds up to 20 hours, same as the Synergy AHB110520CPS original Bose Q35 battery? How is ANC operability affected by it?

I had the same issue with Synergy AHB110520CPS battery, and I went to a local computer and appliance shop if it could be fixed. An IT expert replaced the battery with some other type of battery (I do not even know the type of battery replaced), so here is the outcome: ANC is terrible, about 50% of the previous capacity, I can hear the noise around and the airplane the whine of the engine is no longer properly isolated. The battery draines in 4-5 hours approximately, the charging time is about 25-30 minutes.

Nadrem -

Sounds like the wrong battery. Mine lasts a really long time. I haven’t measured but it seems to last 2-3 8hr work days with some use interruptions. The ANC works still but I haven’t noticed anything different about it tbh. My office isn’t terribly noisy to begin with (and the ANC is only good for background noises like clicks and fans and such, not voices).

It sounds like your battery is no good to begin with. That performance is terrible. Go for a 3.7V max 4.2V, and 500mAh or more (more mAh more capacity).

Maybe the voltage was wrong on the battery? I would expect things to not work well under-voltage. Usually they dont work at all. Maybe it was an old battery or lower capacity battery?

Junrei -

@Junrei I think a better option would be the 10440 li-ion battery. It’s about the same size as the original, usually about 300-400mah so not too big of a difference. I wouldn’t feel too safe with your battery placement right next to your ear. Lipo batteries pack a punch, and can do some real damage to you. The 10440 will fit into the original compartment (I think. Have yet to try.) and will be a little more shielded, should something go wrong.

Dirt Cobain -

Only problem is that there’s no temp sensor on those batteries. I thought those batteries only sizzle a little bit and leak fumes… but I see that they explode when overcharged … this isnt good.

Can anyone find a similar battery that will fit in the original compartment?

Junrei -

Risk is still lower because I’m not charging them when I’m wearing them. I would think damage causing an internal short would eventually cause overheating tho… and possibly the same result.

Junrei -

I just installed the 10440 batteries 5 minutes ago and it fit perfectly. You are correct, they don’t have a temperature sensor, I bought a pack of 10k thermistors and I just glued it to the side of the battery with thermal paste and heat shrink on top. You could also just put a 10k resistor from ground to temp, but you’d lose the temperature sensing.

Definitely look into the 10440’s if you are considering changing at a later time, they’re relatively cheap and are the same size as the original batteries. Thermistors and thermal paste is also dirt cheap. Only downside to the 10440s is that you need to solder the wires directly to the batteries and that requires a decent soldering iron.

Dirt Cobain -

Sounds good Dirt. I’d keep it in a metal pot or other fireproof location for a few days and monitor the temperature every so often when charging. I think without the thermsistor youre removing a safety protection mechanism. When overcharged these batteries explode.

Mine does not even get hot after any time charging so I feel I am safe. Also the battery percentage goes up and down (even to 100%) just like it’s supposed to.

Junrei -

The Partial Teardown instructions show taking both the right and left sides of the phones apart. However, since the battery is in the left side, it it really necessary to take the right side apart if all I need to do is replace the battery?

Barb Pryor -

You are correct. Only take apart the side that has the battery - the left. This guide was meant to be a teardown guide, not just battery.

Junrei -

Just checked the original battery and it seems to be just a 10440 battery with connectors at the top.

https://imgur.com/a/1vCNREx

Not sure if you got notifications for the reply I left on my previous comment, so I’ll just leave a comment here.

Also thanks for the guide. Saved me a lot of time searching for the battery compartment.

Dirt Cobain -

Great knowledge source here! Thanks Junrei, Dirt.

Battery replacement video available.

https://youtu.be/jB-6o_SN4ng

roju1645 -

Is there room to somehow add another battery on the right hand side and wire it in parallel with the left side battery to increase capacity? Having 800mah would be pretty cool. I think if mine ever craps out in me I'll look at mounting two batteries externally on the arms that lead up to the sliding part of the head band and then shrink wrapping them in place with black shrink wrap.

Jan Johnson -

Can I see a photo of the silicon chipset?

Charlie Thompson -

Has anyone tried this replacement battery from Ali?

It’s 14$ now+ shipment. So not cheap, but still better than a new pair..

https://a.aliexpress.com/_BPEKvi

Alexandru Grosu -

Wanted to know what DAC they used… Pretty disappointed no ICs are showcased, isn’t that the whole point of these teardowns?

weeowey weeowey -

What size screws (3 on right side, step 3) are used to secure the metal cover and boards?

Jeff -

#00 Phillips

Austin Smith -