Using an adapter with a higher power rating can damage the disc player or cause it to malfunction. Discmen are usually designed to accept a specific voltage and current input, and exceeding these values can cause damage to the internal components.
For example, if a discman is rated to operate at 5V and 1A, using an adapter that outputs 9V and 2A can cause overheating, damage to the discman's circuitry, or even lead to a fire or explosion in extreme cases.
Therefore, it is important to use an AC/DC adapter with a voltage and current rating that is compatible with the discman. If the original adapter is not available, you should refer to the discman's user manual or consult with the manufacturer to determine the correct power requirements before selecting a replacement adapter.