Saving_the_Sony_CDP-101_CD_Player-service-manual维修手册

SONY4.02RESETLAPDIGITALSaving the SonyCDP-101 CD PlayerWith an Appendix Covering the CDP-200Copyright 2010-2014 by Stephen H.Lafferty.All rights reserved.Rev-3bIn early 1983,I was a design engineer at Wegener Communications,working on the design ofarevolutionary satellite communications system.For the first time(as far as we knew),this systemwould enable network providers to distribute extremely high-fidelity audio over the satelliteThis was called the Panda-II System,based on the development of an advanced and highly accu-rate compander,known as the Panda-II.Years before,we had developed a simpler compander,the Panda-I (at right),which became the satellite broadcasting standard inEurope.It was also quite widely used in the United States.But as we readied prototypes of the Panda-II,we had a problem:There was nosource content that we could get,which would demonstrate the awesome,90-dB dynamic rangeof the system.When Sony released the first CD player in the U.S.that year,the CDP-101,it wasa godsend.Wegener did everything it could to get one as soon as possible,as they were quiterare,at first.When at last our unit arrived,we were told that it was the first one in Georgia.It turned out to be everything we had hoped-for and more.Sony had done it right:5Hz to 20kHzfrequency response,flat to 0.5dB,90dB signal-to-noise ratio (SNR),0.004%harmonic distortionand no wow flutter.The only thing lacking was much in the way of CD's.The first albumcommercially released on CD was Billy Joel's,52nd Street,and another of his albums becameour standard test CD for the compander development.In fact,I remember that the song."Allentown"was the toughest one for the compander to handle,due to isolated high-frequencytransients.After considerable effort,Panda-II was able to handle any transient we could devise.Itwas patented and went into production,later beating a new digital system in customer listeningtests.The CDP-101 played a key role in those tests.In 1985,Panda-II brought CD-quality televi-sion audio from the Live Aid concert to the U.S.,thanks in part,to the pioneering Sony player.Hidden WeaknessLittle did we know,as we avidly used the CDP-101,that inside it had a hidden weakness,whichwas slowly degrading the player.It has since come to light that the modular servo amplifiers(STK6922)used in the unit are prone to failure.To make matters worse,those parts have becomehard to find.(More about that later.)Also,long before they fail,they may cause degraded opera-tion.This could account for a couple comments about bad sound which I have seen on the Web