Sony WM-B52 PCB

The Sony WM-B52 has a single sided printed circuit board (PCB) with conventional components. The circuit, based on the Sanyo LA4570, is very simple with minimal components. Since the electronics might receive exposure to water, this is probably the best way to design it.

LA4570 Audio Chip

This particular unit was under water for a few days, and hence the main chip had shorted out. These units are now becoming increasingly rare because of water damage.

LA4570 Pinout

This single chip package contains two preamplifiers for stereo magnetic heads, and two power amplifiers to drive a pair of stereo headphones with impedance between 16 Ω and 32 Ω. Although the electronic design of this circuit is basic, the sound quality is quite good. The LA4570 is a single chip stereo preamplifier and power amplifier made by Sanyo. The preamplifiers amplify the weak signals from the audio head, whilst the power amplifiers drive the headphones.

PCB Soldering

Here is the PCB section where the audio chip solders.

Audio Chip Replacement: Sony WM-B52 Repair

Chrome / Metal Selector Switch

This is the chrome / metal bias selector switch.

This Article Continues...