Sony Walkman WM-4 Teardown
Background and Identification
The Walkman WM-4 is the fourth revision of Sony’s Walkman series of portable cassette players, first introduced with the TPS-L2. The Walkman WM-4 is the budget version of the preceding WM-1, which is actually the third Walkman, despite its name (don’t you just love confusing product names?). The WM-4 is about three-quarters of the size of the bulky WM-1. The internals of the device require four AA batteries for power, which gives the WM-4 a weight of 410 grams (0.9 lbs).
The cassette player has two 3.5 mm headphone jacks so two people can listen to the tape at the same time. The volume control wheel is located on the top of the device by the headphone jacks along with a switch that allows you to select what type of tape you are playing. The WM-4 supports playing normal tapes (type I), chrome tapes (type II), and metal tapes (type IV).
Sony sold the WM-4 with three different paint colors: red, blue, and silver. You can identify this cassette player by looking for the words “stereo Walkman” on the front and the model number “WM-4” on the side by the play/rewind/eject controls. The most common issue that occurs with cassette players is that the drive belts (little rubber bands that connect the motor to other components) wear out and stretch over time. You can buy replacements for the WM-4 online or get generic belts using the dimensions shown below in the specs section. Peter Vis also has images and great information about the belts in the WM-4 on his website.
- Two 3.5 mm headphone jacks
- Fast forward
- Volume wheel
- Tape type selector
- Four AA batteries
- 87.5 mm x 141.8 mm x 36 mm
- 410 grams (with batteries)
- Battery indicator light
- Plastic clip on back
- Main: 42.5 mm diameter, square, 1 mm thick
- Secondary: 30.5 mm diameter, 0.9 mm thick
Sony WM-4 on Peter Vis (click the links at the bottom for more useful pages of info)
Sony WM-4 service manual on HifiEngine (account required to download the manual)