Sony CDP-C500M

The CDP-C500M was a compact five-disc CD player (CD Changer) manufactured by the Sony Corporation in Japan. It is one in a series of similar players consisting of CDP-C400, and CDP-C401, which were U.S. models without the RM-D505 remote control facility. The CDP-C500 and C400 had variable headphone output ranging from 0 mW to 10 mW with 32 Ω impedance. These devices fall into the category of Compact Disc (CD) digital audio systems and have 780 nm wavelength semiconductor lasers producing 44.6 µW output 200 mm from the lens. These compact units measure 430 mm × 110 mm × 385 mm, with mass 4.9 kg. More information can be found in the user manual.


5 DISC CD Player

At one time in the 80s and 90s, CD changers were very popular, but with the advent of MP3 technology, they lost their lead in the consumer market. However, they are still desirable to many audiophiles who still prefer to listen to their CDs. This CD changer has dual digital-to-analogue converters and a four times oversampling digital filter that produces a rather decent sound. It has channel separation greater than 95 dB (at 1 kHz) and frequency response of 2 Hz to 20 kHz, which is excellent for that time.

This CD player has the µPC75208 (IC401) microcontroller with 4 MHz crystal that manages all the housekeeping functions. For the digital-to-analogue conversion, they are using CXD1161P (IC304), whilst the CXD2550P (IC303) carries out digital filtering. Interestingly, for the line output and headphone amplifier function they are using the M5204P (IC501). This IC provides two solutions because pin 2 and pin 19 provide line outputs that connect directly to their sockets, whilst pins 20 and 1 drive the stereo headphones.


The idea of spinning a disc to read data from it sounds quite low-tech these days, and these technologies can manifest many problems due to the vast number of electromechanical parts that the reading process relies upon. Whilst the CD might have a long useful life of over a hundred years, most people have learned that lasers and motors have a very short useful life in comparison, and these are often the first to fail on an old CD player.

The CDP-C500M and similar models in the series have one common problem, which is when the drawer will not open, and the CDs will not play. In the following pages of this multi-page article, I show how to troubleshoot and fix such a problem.


CD changers have started gaining in popularity in the recent years because after a short honeymoon period with MP3s many people are moving back to their CDs. However buying a used CD changer can be risky as it may be a worn out machine. Often sellers mention that the lights come ON however they do not have a CD to test it with and therefore cannot say whether it is working or faulty. A CD player that requires a new motor or laser can be very costly in terms of time and replacement parts and therefore it is not worth any more than ten pounds these days. However, a unit in good working order can fetch a tidy sum when selling and could command over seventy pounds depending upon the model and condition.

This Article Continues...

Sony CDP-C500M
CDP-C500M inside View
CDP-C500M Electronic Engineering
CDP-C500M Emergency Drawer Open
CDP-C500M Drawer Won’t Open Troubleshooting and Repair
CDP-C500M Chucking Arm Height Adjustment