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Manufacturer: Sony
Model: CDP-C301M
Product: 5-disc compact disc changer
Approximate era: 1990
Status: DOCUMENTED / PHYSICAL MEASUREMENTS COMPLETED / REPLACEMENT FIT TEST PENDING
The Sony CDP-C301M contains two belts:
The Sony part number identified for the toothed timing belt is:
Sony 4-930-528-01 — BELT (TIMING)
An original timing belt removed from a CDP-C301M was physically measured as approximately:
83 teeth × 2 mm pitch = 166 mm pitch length.
Several replacement belts for other Sony 5-disc changers appear in online searches and parts listings but should not automatically be assumed to fit the CDP-C301M.
In particular, the following Sony timing-belt part numbers were encountered during research:
These should NOT be substituted for the CDP-C301M belt solely on the basis of model-family compatibility listings.
Known replacement specifications for these belts did not agree with the 83-tooth original belt physically removed from the CDP-C301M examined for this entry.
When dealing with old Sony changers, verify the actual mechanism, part number, tooth count, and dimensions rather than assuming that similar-looking 5-disc changers use the same timing belt.
Sony’s CDP-C301M/CDP-C305M service documentation identifies the CDP-C500M as a model using a similar mechanism.
Sony CDP-C500M service documentation identifies:
4-930-528-01 — BELT (TIMING)
This part number was subsequently cross-referenced as the timing belt associated with the CDP-C301M.
An original CDP-C301M was opened and inspected.
Two separate belts were physically observed.
The upper carousel/table mechanism contains a conventional rubber drive belt connecting the drive motor to the carousel gearing.
The CD Drive Mechanism contains a narrow toothed timing belt running between two pulleys.
The original timing belt had become loose with age and the changer mechanism was operating inconsistently.
The original toothed belt was removed and manually measured.
| Specification | Measurement |
|---|---|
| Tooth count | 83 |
| Tooth pitch | Approximately 2 mm |
| Calculated pitch length | Approximately 166 mm |
| Belt width | Approximately 2 mm |
| Type | Toothed timing/synchronous belt |
The original belt remained intact but had become loose enough to affect reliable operation.
For diagnostic purposes, a conventional smooth rubber belt of suitable tension was temporarily installed around the two timing-belt pulleys in the CD Drive Mechanism.
The mechanism operated with the smooth belt installed.
This demonstrates that restoring drive tension can restore operation, but a smooth belt is NOT considered a recommended permanent replacement because it cannot positively engage the pulley teeth and may slip under load.
The proper toothed timing belt should be installed when available.
The identified Sony part number is:
4-930-528-01
The original Sony timing belt is difficult to locate.
A replacement sold under this part number was located through a vintage-audio parts supplier in Canada and ordered for physical testing.
Final dimensional and operational verification will be added to this entry after the replacement part is received and installed.
Based on measurements of the original belt, an industrial belt near the following specification may be dimensionally similar:
S2M-166 / 83 teeth / 2 mm pitch
However, commonly available industrial S2M-166 belts are often wider than the approximately 2 mm original Sony belt.
An industrial substitute should therefore NOT be considered verified until tooth profile, width, pulley engagement, clearance, and operation have been physically confirmed.
Sony part number: DOCUMENTED
Two-belt configuration: PHYSICALLY VERIFIED
Original timing-belt tooth count: PHYSICALLY VERIFIED
Original timing-belt dimensions: PHYSICALLY MEASURED
Replacement 4-930-528-01 installation: PENDING
This entry will be upgraded to VERIFIED after the replacement 4-930-528-01 belt is received, compared with the original belt, installed, and successfully tested.
Sony CDP-C301M belt
Sony CDP C301M timing belt
CDP-C301M carousel belt
CDP-C301M CD Drive Mechanism belt
CDP-C301M loading belt
Sony 4-930-528-01
Sony 493052801
4-930-528-01 timing belt
493052801 timing belt
CDP-C301M 83 tooth belt
Sony 83 tooth timing belt
S2M-166 Sony CD player
Sony 5 disc changer timing belt
Last updated: August 2026
This entry is part of the Obscure Product Knowledge Archive, a collection of firsthand repair results, tested fixes, parts information, compatibility findings, measurements, and hard-to-find technical information.