Repair Sony CFD 112 Stereo CD Player Radio Cassette
Date: July 2013
This stereo boombox from the 1990's functions normally in radio and cassette player mode, but it does not read any discs. Once I put a CD in, it will spin the CD briefly and come to a stop. It does not read the TOC (Table of Content) in the CD. It cannot play any tracks. Cleaning the laser lens did not solve the problem.
Unlike the Sharp QT-CD130 CD player that I repaired earlier, I know this one has not been plugged into the wrong voltage. A visual inspection of the main capacitor shows no problem. The previous owner also told me the technician some years ago found trouble with the laser unit and could not find a replacement part at the time.
There are few possibilities, it could be the electronics controlling the laser diode, the laser diode itself, or laser pickup unit. The motor is unlikely to be bad since it spins when a disc is inserted. The most common problem with a CD player of this age is the laser pick up unit, which includes the laser diode.
The laser pickup unit used in many Sony CD players of this era is KSS-210A or KSS-210B, and one thing to pay attention when you are replacing this is to know that it usually comes with a anti-static protection. The laser diode is very sensitive to static discharge and can be easily damaged, so you should take all precautions when handling it. Once you are ready to install the laser pick up unit, remove the solder blob that connects the two contacts for anti-static protection, if you don't remove this particular solder joint, it will not work.
After substituting the laser pick up unit, the CD player spins the disc for several seconds longer each time the disc is inserted, and it reads the TOC and plays with no problem.
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