Battery Cameron Sino for Marshall Mid Major II/III wireless headphones model VDL603040 (replacement, SB8531)

Replacement battery by Cameron Sino designed for Marshall Mid Major II and Mid Major III wireless on-ear headphones. This internal rechargeable cell restores the original device's playback time and enables continued use of Bluetooth functions after the original battery has degraded. The battery is intended for repair and refurbishment of the specified Marshall headphone models and matches the physical size and connector placement required for in-device replacement.

Advantages

The battery provides a direct replacement option that preserves the headphones' original form factor and fit. It restores operating time without requiring external charging accessories and is manufactured to meet typical safety and performance expectations for small lithium polymer cells used in audio headsets. Using a compatible replacement cell can extend the service life of the Marshall Mid Major II and Mid Major III headphones and avoids the need to replace the entire headset.

Suitable for

• Repair or refurbishment of Marshall Mid Major II on-ear headphones
• Repair or refurbishment of Marshall Mid Major III on-ear headphones
• Replacing a worn or degraded internal rechargeable battery to restore playback time
• Use by technicians and experienced DIY users comfortable with disassembling headphones

Key specifications

• Cell type: lithium polymer rechargeable cell
• Nominal form factor: pouch cell sized to fit the Mid Major II/III battery compartment
• Connector: small internal headset battery connector compatible with the original cable arrangement
• Intended use: internal power source for wireless on-ear headphones

How to use

Install the replacement battery by opening the headphone earcup that houses the original cell, disconnecting the original battery connector, and connecting the new cell in the same orientation. Ensure the replacement cell is seated and secured in the compartment so it does not interfere with moving parts or wiring. After reassembly, fully charge the battery before normal use and verify Bluetooth pairing and audio playback. Follow safe handling procedures to avoid puncturing or shorting the cell during installation.

Usage recommendations

Only attempt replacement if you have appropriate tools and experience with small electronics; consider professional repair services if unsure. Use recommended charging accessories and avoid exposing the battery to high heat, moisture, or mechanical stress. Dispose of the removed battery in accordance with local electronic waste regulations.