Please use mobile earphone as headset A then test B.
*If the headset B still doesn't work, please change SD-SPK for the headset B.
*If the sound is normal, the problem might be the MIC on headset A.
Please change SD-MIC for the headset A.
Video: https://www.youtube.com/watch?v=hepW9oSO660

*You also could clean the pin by METAL POLISH.
1. Dip some cream with a tissue.
2. Wipe the pin by circle until there is no dirt on it.
3. Use another tissue to clean it again.

Take care tips:

*After each use, take off the sponge and rinse your BbTalkin headset thoroughly with
fresh, clean water. (especially microphone and speaker)
*Dry naturally in a clean, dry, cool area.
*And away from any heat source, prolonged direct sunlight.
If you already changed SD-SPK / SD-MIC (or already test by mobile earphone),
and the headset still have noise. It might be ADV units’ issue.
Please ask the customer send back the unit and you need to check inside.
If it isn’t water damage, you could give the new unit as warranty.

ADV unit

1. When you open the case, you will see the battery first, please take it out.
2. Then you can see the first side of PCB.

3. Unscrew it again, then you can check another side.
(This one is OK, no water damage)

If want to speak individually by ADV

Advance units work like a chain,
1st device CH2 connect to 2nd device CH1, 2nd device CH2 connect
to 3rd device CH1.
(Please look the photo below)
If you would like to have individual channel for each students,
you'll need 5 devices for yourself and 1 for each students, total 10 devices.
For long range communication, we don’t suggest more than 3 way talk

Advance pairing like a chain 1—2—3—4
If 2 is gone, only 3 and 4 can talk.

If they get out of order, like 4—2—3—1
or if 1 is in the middle and surrounded by 2,3,4
it's still can work.

*As our support team experience,
the connection of land to water have least problem. It's the best situation to use the device.

Boat to water, we only try it on wakeboard, it's also not much of a problem.

Water to water, it's the worst connection for devices. Maybe will get disconnect.

Therefore, keep the unit same and instructor teaching on the land is the best option.
(We had black units and this is the old one)

Reason influence communication:

1. The air environment nearby may has 2.4Ghz frequency such as cell phone wifi,
Bluetooth, Wifi Router, Cordless Phone, RC toy etc. will reduce RF energy.
2. The physical environment:
Obstacle like Walls, Trees, Waves, houses etc. will reduce RF(radio frequency)
3. If both people are in the water, the distance will be shorter.
4. Reconnect problem: within 300m can click button 1 to reconnect the units.

*Communication distance is much better if you mount the main device on your head.

The reasons that cause battery expand has:

1) AC adopter is over 5V.
2) It was out of power last time when you storage it.
Meantime, doesn’t use the unit for long time (few months).
The battery will keep discharge the power and influence the PCB working while
storage. So the battery will expand, and PCB may damage too.

When ADV can't turn on:

Please confirm its full charge first (RED is charging, BLUE is full charge).
Second, reset the unit (Press POWER and VOL+ for 3-5 secs)
Then try to turn on the power while plug in the charge cable.
If it can turn on the power, it may be battery loosen.
If not, it may be PCB problem.
(Please get the unit from the customer and check if it’s water damage)