CD-Player - Ralph Toman
Contents
1. 1 10 Test CD ont 2 3 1 11 Square wave signal on measuring junction Focus Offset 1 12 Pushbutton for the Service Mode u anan ennen en ennnen ennen vennen 1 14 Status 08 15 2005 Ill www ralph toman de Repair CD Player List of abbreviations EC emme E rn emo OOO om Status 08 15 2005 IV www ralph toman de Repair CD Player List of appendices Laser Ge Fs Loos EEE AE eR ee en nee ee tee eee re A 1 ACYCSSEGS ccccececcccececcccececccecacececaceaceceneacaceceaueueceacaueaeacaneauetaneaueteceaueeceaneceanenss A 2 Status 08 15 2005 V www ralph toman de Repair CD Player 1 1 1 2 1 2 1 1 2 2 Description Introduction Repairing CD players is hardly worth nowadays as labor in craft is quite expensive and you can get a new player at a very low price One example A CD player approx 5 years old doesn t play the CDs any more The costs estimate amounts to approx 30 Euro The repair costs however can increase up to 100 Euro In this case would say repair isn t worthwhile since you can buy a new player for about 49 Euro as a special offer These players do even play Mp3 files and DVDs Furthermore a new player is covered by guarantee This instruction shall help to repair CD players which are not worth to be repaired through specialist shops Copyright Exclusion of Damages Liability Copyright All texts and graphics of this document are protected by copyright if not i2. Player Eject the CD and switch off the CD player Press the small key button 1 on the main printed circuit board and keep it pressed Switch off the CD player Using the buttons Forward Reward and Play you can start the focusing process without an inserted CD and you can move the laser unit back and forth completely Eject CD and switch off CD player In this way you can easily approach the lens The following figure shows the small key button 1 Fig 1 9 Pushbutton for the Service Mode Finally a short comment for adjusting the potentiometers As man hours in production are very expensive Philips decided to go a different way A CD player was produced Then it was aligned optimally The potentiometers positions adjustments were photographed for the alignment regulations This made is easy to set the potentiometers on every new CD player do not know if the players were tested afterwards lf 5 of 100 CD players were sent back because they didn t function due to a wrong alignment this was okay for the company These players were scrapped the customer got a new player An alignment would have been too expensive If this is still practiced nowadays do not know Anyone who knows something about it can send me an e mail if he she likes ralph toman t online de Status 08 15 2005 IT www ralph toman de Repair CD Player 1 5 4 Mechanical alignment In the previous sections we assumed that the mechanics wasn t misadjusted
3. Table of contents Part 1 Description CD Player Appendices Repair instructions for most CD players English Author Ralph Toman Internet http www ralph toman de e mail ralph toman t online de www ralph toman de Repair CD Player 1 1 1 2 1 2 1 1 2 2 1 3 1 4 1 5 1 5 1 1 5 2 1 5 3 1 5 4 Table of Content De DUO Nea Ernest 1 1 INLOGUCHON Eee 1 1 Copyright Exclusion of Damages Liability Rennen 1 1 GONE aeerereceeererrsererterre rr terete err etrr reer sere err rer trerere reer rr rrr ere errr 1 1 EXCIUSION Of Damages ETAO sesszsesseasaueseusseqsssuansesssuancuspeeausuentessaess 1 1 S alely INSHUCHONS prendre erde 1 2 Rules for working with electrostatic sensitive components or MOGUC Scat ao os tae eae ee 1 2 Repar INSIMUCUON sunshine 1 3 Gleaning thellensa s seisiseiseniana 1 5 INGFEASING Inelaser Cun oTi aan a 1 7 Alignment of the CD player u 222u02222seenenneennnnnenennnnnennennenne nennen 1 10 MECHAAICAL AIGAMENE rnrnDe 1 15 Status 08 15 2005 Il www ralph toman de Repair CD Player List of illustrations Fig Fig Fig Fig Fig Fig Fig Fig Fig 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 CGOVEE OR ASF PICKUP nn 1 5 FEU SN EL EEEN 1 6 Measuring junctions on a Technics CD player nnen 1 7 Osellogram o AE EFM esise 1 8 Pick Up with potentiometer in a Pioneer CD player ennen 1 9 Printed circuit board of a Technics CD player un annnn eneen
4. and a mechanically perfect CD was inserted into the Disc tray Another reason for the CD player not functioning properly is an unbalanced CD or a slightly misadjusted mechanics Unfortunately the mechanical alignment cannot be described generally for all CD players Anyone who wants to perform a mechanical alignment must order the service manual for his her CD player However not every service manual describes a mechanical alignment It might be better to contact the manufacturer to get information if there is a description available at all It is worth asking since the prices for a service manual can amount to 30 Euro See the appendix for addresses of companies that offer schematic diagram lf an unbalanced CD has been inserted it must be replaced by a perfect one If you use an oscilloscope to look at the HF you will see the amplitude pumping voltage height This pumping must be reduced to a minimum In order to function perfectly the mechanics has to be greased The laser is moved over the whole area via two rods that are mounted sideways it The laser is powered by spindle that is driven by a motor Those rods and the spindle are greased If the is not enough grease or it resinified new grease has to be used for re greasing A good brand for greasing is Ballistol Simply use an ear swab for putting some grease on the rods and make sure the motor moves the laser from one side to the other and this way spreads the grease consistently T
5. clean then Another problem can occur The disk drive doesn t rotate at all In such a case the motor can be faulty actually this is seldom the case or the focusing doesn t function any more The latter can easily be checked Hold a CD quite near the lens and check if the lens moves up and down lf this is the case the CD player tries to find the optimum focusing i e focusing functions correctly Mostly the following 3 reasons are responsible for the main defects a Laser lens is dirty a Laser is not strong enough a The device needs to be readjusted lf you have checked or cleared these 3 error sources and the CD player still doesn t function certainly the laser must be replaced This however isn t worth if the player cost about 100 Euro In the following will explain step by step how you can try to get the CD player started and work properly Status 08 15 2005 1 3 www ralph toman de Repair CD Player Basically If you change the position of the potentiometers mark the original position before also like to turn the potentiometers but if e g turn more than 1 potentiometer often forget the original position of each of them one potentiometer adjusted incorrectly can disable the entire CD player You need the following material Cotton buds ear swabs Isopropyl alcohol screwdriver for recessed head screws Small screwdriver for slotted screws DO O0 U DO One 2 channel oscilloscope for the alignme
6. efore performing the tasks To do so touch grounded metallic objects Use grounded measuring devices only e The components must remain in their packaging until they are actually needed e Once it has been disassembled a defective module must be placed in its original packaging e The converter must be switched off before modules are assembled or disassembled e Neither test voltage nor signals must be applied to the modules until the device has been switched on 1 5 Repair instruction You ve loaded a CD into your CD player but the player doesn t play it What can you do Those of you owning a 2 channel oscilloscope or those who can borrow one can try to get the CD player started quite easily But even without an oscilloscope you can take remedial action e g if you follow the chapters 1 5 1 and 1 5 2 mentioned below The following should be said to alcohol isopropyl alcohol can be bought at the chemist s where it is very cheap Ethyl alcohol would be an alternative it is comparable but much more expensive Ethyl alcohol is drinkable isopropyl alcohol is not A certain substance makes it undrinkable It s the same with methylated spirit For our purposes the cheap alcohol will do Isopropyl alcohol will leave a white thin coating on the surface of the lens after it is evaporated This is the substance mentioned above However it is no problem you can simply use the dry end of a cotton bud to wipe it off The lens will be
7. er has already reached its limit stop then this is quite suspect Even if the CD player is functioning now you can assume that it won t last long A potentiometer at its limit stop is never good If this procedure Status 08 15 2005 1 9 www ralph toman de Repair CD Player 1 5 3 hasn t helped to get the CD player working an alignment is necessary see the following chapter Alignment of the CD player Principally there are two different types of CD players The older versions have got potentiometers on their printed circuit board The following figure shows the printed circuit board of a Technics CD player You can clearly see the yellow potentiometers 1 2 and 3 which are used for the alignment On newer CD players the alignment is done automatically So if your CD player is a modern one you cannot in fact do much assume that you have got a device with all the following potentiometers Status 08 15 2005 1 10 www ralph toman de Repair CD Player Tracking Gain Tracking Offset Tracking Balance isn t always available FG Focus Gain PDB Best eye in Technics devices TG TO TB 0D O UO U DOD Furthermore we need a test CD and a black gum tape approx 0 9 mm broad and impervious to light This must be adhered to the bright side of the CD NOTE The tape must not pass through the middle of the CD Otherwise the CD might not be recognized the information is in the inner edge of the CD TOC trac
8. he ICs until you ll see the signal The characteristic is that the beams are bundled in the middle What you cannot see in the figure is that a lot of sinusoids are lying on top of each other Here they are displayed only blurred Fig 1 4 Oscillogram of HF EFM NOTE The HF signal is mostly positioned where the main printed circuit board is connected to the laser via the flat cable NOTE Unfortunately the laser life is reduced by increasing the laser current However this is mostly the last option Status 08 15 2005 1 8 www ralph toman de Repair CD Player As soon as you have found the signal increase the laser current The appropriate potentiometer 1 is positioned either directly on the laser or on the flat cable connecting the laser unit with the big printed circuit board The following figure shows the potentiometer clearly 1 2 ri k TaN a d ed le De un Va mn L eef Wok N Fig 1 5 Pick Up with potentiometer in a Pioneer CD player After you have found the potentiometer turn it very carefully and simultaneously observe the HF signal ATTENTION lf you turn up the potentiometer too quickly the laser might get too much current and the laser diode will break Therefore turn it only slightly observing the oscillogram Potentiometers are often sealed with lacquer Turning the potentiometer can cause an uncontrolled jerk The amplitude must increase In most cases this is sufficient If the potentiomet
9. his might happen by putting a 80 min CD into the player Status 08 15 2005 1 15 www ralph toman de Repair CD Player Laser Classes Depending on the potential endangerment through the accessible radiation laser units are divided into classes 1 2 3A 3B and 4 1 1M 2 2M 3R 3B and 4 Class 1 Class laser products produce no accessible laser emissions For example a CD player or DVD player recorder contains an internal laser to read or write data but does not actually emit any laser light Products of this type are Class laser systems Class lasers products present no hazard at all unless they are disassembled to gain access to the internal components Class 2 Class Il laser products can emit up to 1 milliwatt 1 1000th watt of accessible laser emissions Low powered laser pointers data and telecommunications gear and some scientific systems use lasers of this output classification Class Il laser products are not capable of causing permanent eye injuries but can still be quite hazardous due to glare and temporary flash blindness Class 3A Class Illa laser products can emit up to 5 milliwatts 5 1000th watt of accessible laser emissions The most common laser pointers and all inexpensive laser display systems fall into this output classification Class Illa lasers pose an eye hazard with prolonged exposure and should not be directed towards the eyes or face and should never directed into or out of a moving
10. k The following figure shows a test CD Fig 1 7 Test CD After the CD has been prepared as described before insert it into the CD player The potentiometer positions adjustments are marked What s www ralph toman de Repair CD Player important now is if the CD player can read the CD at least If no reading is possible this alignment cannot take place The entire laser could be defective In order to check this get all potentiometers into center position Then take the CD from the drawer and check with the naked eye if a red beam can be seen in the laser The laser beam is a dark red point and you should see it on the surface of the lens if you look onto the lens slanting your head CAUTION Do not look directly or for a prolonged time into the laser beam just glance at it The laser is very weak but can however cause health damages See also laser classes in the appendix Now connect channel A of the oscilloscope to HF and channel B to the measuring point Focus Offset If you do not find this point look for it until you see an oscillogram showing small square pulses the square pulses are the black stripes on the CD The following figure shows the oscillogram Fig 1 8 Square wave signal on measuring junction Focus Offset Next the Focus Gain will be set If you turn up the appropriate potentiometer you can hear how the lens grinds on the CD Turn the potentiometer back until grinding noise stops If you
11. ndicated differently It is also not allowed to print extracts of the text If you want to publish this instruction on your website please send an email to ralph toman t online de will then decide whether this instruction may be published on the respective site Exclusion of Damages Liability In no event shall be liable for any damage whatsoever including but not limited to damages for personal injury arising out of the application of this instruction Protection measures are strictly to be observed High voltages exist in CD players and if you come into contact with them it could be life threatening During repair activities safety regulations have to be observed in order to avoid damage caused by short circuit electric shock or fire The author does not assume the liability for consequential damages to persons and or any kind of equipment or the accuracy and completeness of the data Status 08 15 2005 AA www ralph toman de 1 3 1 4 Repair CD Player Safety instructions Meaning of warnings and notifications in this operating manual CAUTION ATTENTION NOTE Disregard can lead to seriously injuring the operator and to equipment damage Disregard can lead to malfunctions and damaging the equipment Important additional information Rules for working with electrostatic sensitive components or modules A Alas ATTENTION All electronic modules are equipped with highly integrated chips or compone
12. nt The following error symptoms can occur a The CD player doesn t recognize the loaded CD a The CD player recognizes the CD but doesn t play it a The CD player doesn t play all songs a The CD jumps while it is played Status 08 15 2005 4 www ralph toman de Repair CD Player 1 5 1 Cleaning the lens First of all you have to remove the cover of the casing to clean the laser lens You might have to remove the hplastic part above the laser to reveal the lens This part is mostly fixed with plastic catches and may be connected with a spring The following figure shows a Pioneer CD player The plastic part 1 has to be removed using the two plastic catches 2 Take a small screwdriver and push the catches to the left At the same time slightly lift the plastic part 1 Fig 1 1 Cover of laser pickup Status 08 15 2005 1 5 www ralph toman de Repair CD Player After the cover has been removed you can see the laser unit with the lens 1 see figure 1 2 You can also see a part of the flat cable and the longitudinal guide of the laser On the left and on the right side a rod 2 is situated Two rings made of plastic 3 surround each rod 2 The following figure shows this very clearly A good lubrication ensures a smooth guiding See also chapter 1 5 4 Mechanical alignment Fig 1 2 Pick up laser Now the lens is uncovered Use a cotton bud and pure alcohol or methylated spirit to clean the laser Please do n
13. nts The engineering of these electronic components makes them extremely sensitive to over voltages and thus sensitive to static electricity discharges as well The acronym ESD or electrostatic sensitive device is used to describe such components Electrostatic sensitive modules are identified by this symbol Electronic components and modules must always be protected against electric charging and discharging For this reason the following measures must be observed for components or modules that are being tested or installed Electrostatic sensitive components or modules must not get in contact with materials which are chargeable including all standard types of plastic Any person not conductively linked to the ambient electrical potential can be electrostatic charged Rules for working with electrostatic sensitive components or modules e Ensure that persons the work area and packaging have proper grounding when working with electrostatic sensitive modules This avoids static charging e Avoid any contact with electrostatic sensitive modules unless it is inevitable e g for maintenance Handle the modules in such a manner that contact with either the component pins or strip Status 08 15 2005 1 2 www ralph toman de Repair CD Player conductors are avoided This will prevent discharge energy from reaching and damaging sensitive components If you must carry out measurements on a module ensure to discharge yourself b
14. ot use vodka or something similar as vodka contains additives the lens would be soiled Take the cotton bud and wipe the lens carefully The lens is supported by a spring If you press the lens too strongly it may not get back to its original position The laser would be faulty then Use the dry end of the cotton bud to complete the cleaning Afterwards you can try if the CD player functions If not continue with chapter 1 5 2 Status 08 15 2005 1 6 www ralph toman de Repair CD Player 1 5 2 Increasing the laser current The laser current has to be increased Depending on the type of the CD player the measuring points are on the big printed circuit board Sometimes the measuring points are pins In the case of the Sony CD player the measuring points are jumpers with a big splodge of solder in the middle Other CD players do not have something similar The measuring point HF or EFM must be looked for This is not easy in some cases because some devices do not have points at all The following figure shows a Technics CD player The measuring points are jumpers wire straps Jumper no 1 is the GND jumper no 2 has the signal EFM and jumper no 3 is the jumper where you can measure the signal Focus Offset Fig 1 3 Measuring junctions on a Technics CD player Status 08 15 2005 1 7 www ralph toman de Repair CD Player If you do not find a measuring point look at the oscillogram see the following figure and search on t
15. turn too much the CD player stops Perform the same procedure with potentiometer Status 08 15 2005 1 12 www ralph toman de Repair CD Player Tracking Gain and afterwards with potentiometer Focus Offset HF dropouts should now be visible There must not be any time shifting Perform this procedure with potentiometer Tracking Offset If your CD player has got the potentiometers PDB and E F Balance set them so that the HF looks as clear as possible i e shows as little film as possible If the CD player doesn t function yet repeat this alignment or reset one of the potentiometers You can assume that 80 of the CD players will function after the instructions mentioned above have been followed If your player is one of the remaining 20 it is uncertain if a new laser unit is worth to purchase In fact cannot claim that the player doesn t function only because of the faulty laser If the player is still faulty would suggest to take it to a specialist shop or to someone else who knows a lot about CD players A further test is described in paragraph 1 5 4 This paragraph deals with the mechanical alignment Just a comment to the electrical alignment The service manuals often describe how to activate the service mode Sometimes this mode is quite helpful you can check the laser without inserting a CD The service mode of a Pioneer CD player is activated as follows Status 08 15 2005 1 13 www ralph toman de Repair CD
16. vehicle Class 3B Class Illb laser products can emit up to 500 milliwatts Ye watt of accessible laser emissions Some scientific and medical systems and low powered laser display systems may be classified into this category Class Illb lasers are capable of causing a permanent eye injury with brief exposure Can Cause minor skin burns and can ignite many materials with sustained or focused exposure Class 4 Class IV laser products emit any amount of power greater than 500 milliwatts 1 2 watt Industrial laser systems research scientific and medical lasers and the largest laser display systems are Class IV laser products Class IV lasers can cause permanent eye injury before you can react can cause serious skin burns and can quickly ignite flammable materials at a considerable distance Status 08 15 2005 A 1 www ralph toman de Repair CD Player Addresses Schaltungsdienst Lange Zehrensdorfer Str 11 12277 Berlin Tel 030 723 81 3 Fax 030 723 81 500 http www schaltungsdienst de Schaltplandienst M nchen Inh Robert Martyson Greinerberg 10 81371 M nchen Tel 089 157 80 771 Fax 089 157 80 772 http www schaltplan dienst de Status 08 15 2005 A 2
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