Technics EAH-AZ40P-S Bluetooth Headphone Teardown

ID: 147458

Description: A look inside the Technics EAH-AZ40P-S...

Superior Call Quality with JustMyVoice™ using an Utterance Detection MEMS Microphone
Ambient Sound Mode
6mm Driver units with PEEK diaphragm
7.5 Hours Playback
Alexa Enabled
Cheaper Bluetooth Ear Phones then the Technics AZ60 but still has utterance detection support

The headphone touch sensor cap is glued onto the headphone. The only way in was to gently used a Xacto knife to break the glue seal
Once a the touch sensor cap gave a little, a Jimmy Tool was used to pry the cap from the headphone body
Since the headphone was easy to open, it may be possible to perform a battery change without damaging the headphone
Once the headphone was open, we get our first look at the inside of the headphone
Bluetooth Radio / MCU
Battery

Before removing the battery, it was unsoldered from the MCU PCB. This was safety measure, so the that the battery could not be accidentally shorted during the teardown. It is recommend to unsolder the battery in any teardown where it is soldered in and not easy to remove to reduce the change of problems
The battery was pried out using a small flathead screw driver
The battery is a Li-ion 3.7V / 0.2Wh or 3.7V / 54mAh
Was not able to the the vendor of the battery. If you happen to know the battery vendor. Please leave it in the comments

There is a a Phillips Head ##00 screw that holds the MCU board in place in the headphone
Removing the MCU screw allows the MCU to be pried out with a small flathead screw driver

With the MCU PCB removed, we can see the Touch Sensor and Bluetooth Antenna Interface Board
MCU PCB
Touch Sensor and Bluetooth Antenna
Battery
The MCU PCB Interfaces to the Touch Sensor and Bluetooth Antenna via pogo pins

The Touch Sensor and Bluetooth Antenna PCB was pried out with a flathead screw driver
The Touch Sensor and Bluetooth Antenna PCB is held in place with double sided foam tape

Pulling off the double sided foam tape, we can see the Touch Sensor and Bluetooth Antenna structure

To release the MCU PCB from the headphone, we can pop the retention clip interfacing the MCU to the headphone via the flex ribbon cable
Pulling the flex cable from the retention chip frees up the MCU board, but the MCU PCB is still attached to the speaker

Now, we pop of the other side of the flex cable from the retention chip, so that we can pry out the Power, USB, and Utterance Detection Microphone PCB
This PCB is also held in place with double side foam tape

Now we can remove the speaker from the headphone. The speaker is held in place with double side foam tape, so it best to use an Xacto knife to cut around the speaker. Then the speaker can be pried out with a small flathead screw driver

Now with the headphone dissembled, we can turn our attention to looking at the components that make up the headphone. We will start with the MCU PCB
AIROHA AB1565M - ARM Cortex M4/Bluetooth 5.2 Dual Mode with Active Noise Cancellation
MEMS Microphone. Not able to cross the part. The part has the following markings: 2C4 1X7. If you happen to know the part, please the part information in the comments
Crystal Oscillator
MEMS Microphone. Not able to cross the part. The part has the following markings: 6C2 1D7. If you happen to know the part, please leave the part information in the comments
Battery Management IC. Part Markings 651DE1M0 13Q0W52C
Could not cross the part. The part has the following markings: SV4CP 2H0. If you happen to know the part, please leave the part information in the comments

Close up view components on the Front Side of MCU PCB
MCU with Bluetooth
AIROHA AB1565M - ARM Cortex M4/Bluetooth 5.2 Dual Mode with Active Noise Cancellation
Close up of the MEMS Microphone
MEMS Microphone. Not able to cross the part. The part has the following markings: 2C4 1X7. If you happen to know the part, please the part information in the comments

Close up view of components on the Backside of MCU with Bluetooth
MEMS Microphone
Not able to cross the part. The part has the following markings: 6C2 1D7. If you happen to know the part, please leave the part information in the comments
Battery Management IC
Part Markings 651DE1M0 13Q0W52C
Could not cross the part. The part has the following markings: SV4CP 2H0. If you happen to know the part, please leave the part information in the comments

We can not turn our attention to the Power, USB, and Utterance Detection Microphone PCB
The part number on this component was not readable, but it location near the power interface may mean that it is either a Diode or PMOS FET
Vesper VA1200 - Analog Piezoelectric MEMS Voice Accelerometer. Bone Sensor - used for Utterance Detection
Light based Proximity Detector. Detects when the microphone is in the ear canal or in the charger

Close up view components on the Front Side of Power, USB, and Utterance Detector PCB
The part number on this component was not readable, but it location near the power interface may mean that it is either a Diode or PMOS FET
Vesper VA1200 - Analog Piezoelectric MEMS Voice Accelerometer. Bone Sensor - used for Utterance Detection

Close up view components on the Backside of the Power, USB, and Utterance Detector PCB
Light based Proximity Detector. Detects when the microphone is in the ear canal or in the charger
Light based Proximity Detector with cover removed. The Transmit and Receiver LEDs can be seen.

Close up view of the front and the side of 6mm Driver (speaker) with PEEK diaphragm
No part number found on component. If you happen to know the component please leave the component information in the comments.

Close up view the Microphone interfaces to the topside [Touch Sensor / Antenna Cap]
MEMS Microphone Interface
MEMS Microphone Interface

Teardown Exploded Top Side and Backside views of the Headphone
This teardown showed that with little effort the batteries in the headphone could be changed out.

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