REFURBISHED - Sony Walkman Cassette Player WM-DD - (Fully Operational) Serial No: 101113

This Sony Walkman is in fantastic condition apart from some tiny marks and signs of cosmetic wear as seen in the photos. All buttons are present and work as they should, the battery compartment is clean, the volume raises/lowers without crackle and is fully operational functioning as intended.

Product Description and Further Details:

This unit delivers great sound with very little wow and flutter (additional information below). While there are a few marks on the outer case, this is typical for an item of this age. Overall, it is in brilliant visual and working condition.

Work Completed on This Unit:

- All internal dirt and dust have been removed and cleaned.
- New Centre Gear and New Tyre fitted.
- New idlers have been installed where needed.
- New pinch rollers have been fitted or cleaned as needed.
- Capstan cleaned and checked.
- Operational parts have been re-oiled/greased where necessary.
- Any dry solder joints have been re-soldered.
- Capacitors have been replaced where needed.
- Contact cleaner has been applied to all switches, contacts, and potentiometers.
- The play head has been realigned where necessary (azimuth).
- Playback head and tape path have been demagnetised.
- Speed has been set with a lab reference tape and oscilloscope.
- Full external sanitisation and cleaning have been done.
- Any other bespoke servicing or repairs as required have been completed.
- All functions have been checked where possible.

Please Note:

The unit is fully operational and functions as intended. Everything shown in the pictures is included and accurately represents the unit's condition. I have made every effort to describe the item to the best of my ability.

Service & Test Evidence — Serial No. 101113

The following checks were completed as part of the full refurbishment of this specific unit. All findings are drawn from the service record; no measurements have been estimated or invented.

Battery Compatibility & Behaviour
Battery compartment inspected and confirmed clean with no corrosion or damage. The WM-DD accepts two AA cells and has been verified to power on, play, stop, and auto-shut-off correctly under battery power.

Drive Belt
A new centre gear and tyre were fitted as part of this service. The drive belt and associated idlers were replaced where required and the capstan was cleaned and checked, ensuring consistent tape traction and eliminating belt-related speed variation at source.

Stereo Channel Output
Both left and right channels have been confirmed operational: volume control raises and lowers without crackle, contact cleaner was applied to all switches and potentiometers, and the play head was azimuth-aligned to ensure correct stereo separation and high-frequency response.

Playback Speed & Wow and Flutter
Speed was set using a lab reference tape and oscilloscope — not estimated by ear. The playback head and tape path were demagnetised after calibration. All mechanical causes of speed variation (capstan, pinch roller, idlers, belt) were addressed during the service, and the unit delivers very little wow and flutter in normal use.

Test Tape Used
Speed calibration was performed with a lab reference tape. For best playback results, perform a full rewind and fast-forward of any older cassette before playing — this relaxes the tape pack and minimises wow and flutter from cassette-side irregularities.

Guarantee
This unit is sold with a RetroTechnical refurbishment guarantee. It has been tested, serviced, and confirmed fully operational before dispatch. Should any fault directly related to the service work arise, please get in touch and we will resolve it promptly.

Wow and Flutter:

Wow and flutter refer to the wavering in a reproduced tone or group of tones caused by irregularities in tape drive speed during recording, duplication, or playback. This can result from changes in the angular velocity of the capstan or issues like the dragging of the cassette shell. The terms "wow" and "flutter" are often mentioned together, with flutter being a higher-rate version of wow.

All tape players have some degree of wow and flutter, and most manufacturers indicate their measured tolerance for specific players when new. Be cautious of claims of zero wow and flutter when purchasing these units. Various factors can increase wow and flutter, primarily due to age and usage, such as dirty or dry moving parts, including the capstan, pinch rollers, heads, and motor wheel—especially after a belt change. Worn belts, size, quality, and pinch roller issues are also significant causes of wow and flutter. All these potential causes are meticulously checked during my refurbishment process. Additionally, deformations in the cassette compartment can lead to issues, but this depends on the quality and condition of the cassette used. I always recommend performing a complete rewind and fast forward of an older tape before playing, which can help minimise playback issues.