Join Date: Dec 2009
Location: Chesterfield, UK
Sony CDP-CX355 mabuchi replacement & Digital out
I recently bought a Sony CDP-CX355, a 300 disk changer, on Ebay. It had been previously sold but had been damaged in transit by Parcelfarce and returned to the seller. After buying it for a good price, I set about fixing it. I checked the boards were intact and all connectors in place. Everything seemed to work, but no movement from the laser. On inspection, it had been badly bashed, with the optics wedged under the protective cover, and it's mounting bent out of shape. It's a bog standard KSS213B, so I bought a new one from a reputable UK based supplier. Unfortunately, after replacing the laser, it still wouldn't read a CD. I removed the mechanism and began checking the board.
To cut a long story short, it was clear from the voltmeter that one of the Mabuchi motors was not getting power. I unscrewed the single screw on the PCB, then de-soldered the four solder pads holding the PCB to the laser mechanism (as arrowed on the image 1). After taking the board off, one of the lugs had sheared from the motor controlling laser movement, so I set about replacing it. I had a donor laser, so I removed a motor and gently pried off the plastic gearing.(See image 2)
I did the same on the target mechanism, and swapped the gears. This was necessary as the gearing between the two mechanisms was not identical. On replacement, I set about re-soldering the PCB and testing the machine. "Bu**er!", said I, as the damn thing still didn't budge. After a moments thought, I asked myself whether the motors had to be inserted in a particular orientation. Checking the dead motor, it was found there was a red dot next to one of the tags (see image 3). I undid the work and checked, and sure enough, I'd got it wrong. I turned the motor through 180 degrees and re-soldered the tags as before. On rebuilding the mechanism, all worked as it should. I hope this tip will be useful to someone, because it was news to me!
The only other thing of note, was the construction of the PCB & laser. It reminded me of a boom box, where all the chips are attached to the mechanism, not unlike the excellent Shigaclone threads initiated by Peter Daniel. Sure enough, there is a direct digital out on the board (See image 4). I'm sure there must be many similar boards knocking around, but if anyone is interested, there appears to be the capability to add a valve or JFET buffer, or a direct connection to an external DAC, without using the built in optical output on the Sony. I'm a fan of the Lampizator, so I think I'll give his valve buffer circuit a spin.
Last edited by Beacon64; 10th August 2013 at 07:33 PM.