B&O Beosystem 2500 (type 2606): CD not recognized

On my workbench is a B&O Beosystem. The symptoms are: CD is not recognised, CD won’t start spinning.
In most cases these machines have worn belts for the glass doors, CD cover and tape deck. Most also have doors that need adjustments. This one was no exception, but I discovered that the CD was also not working. Let’s see what is going on:

To understand where to look for the defect, we need to know the steps it is going through upon initialisation. The steps are for most CD players the same, except for the start of the spindle motor that turns the CD. In some cases the motor is started in the early phase, but mostly when a cd is “seen” by the laser. That is: laser light is reflected onto the CD and picked up by the laser pickup sensors.

The steps are as follows:

  • When CD tray/door is closed
  • Move Laser to starting position*
  • Turn on laser light
  • Start focussing sequence (Depending on system, repeat this several times, sometimes move the laser tracking position.
  • When CD is detected, start spindle motor.
  • Look for lead in track and read TOC (Table of Contents)

*) Linear tracking and radial tracking servos move the laser to the start position when this process is started. That is not the case when motor/gear tracking systems are used. With that system the laser is mostly moved to the beginning of the CD upon power on, upon CD tray close/open and upon stop command.

Focus sequence not working

With the knowledge of these startup steps I started to test the system with and without a CD in the player. The spindle motor was not started and the CD was not recognised.
Without a CD in the player, I could see whether the laser tries to find a CD and tries to focus on it. That wasn’t happening at all, also the laser was not moved to the center of the CD. So that makes sense that the CD is not detected. I know that this Philips based system uses no feedback on laser light “on”, so it would try to focus anyway regardless of whether the laser is on or not.

After I mechanically loosened the CD cover, I could safely try to confirm that the laser in deed was working. Gently because I didn’t want to damage my eyes. I had a quick look at the laser from a distance and from an angle while keeping the laser in the shadow of my hand. A little faint red dot was enough for me to see and know that the laser was fine.


I started to see whether there is any voltage on the tracking and focus servo, there was nothing on there.
Next I checked the schematics to see how the tracking and focus servo are driven:

Focus and Tracking servo schematics

There is one half of a dual opamp used for driving the focus servo, the other half for the radial tracking servo. I first checked the positive and negative power lines, both were not present. In the schematics the negative power line is pictured on the focus servo opamp, the positive is on the tracking opamp. Both power lines have 1 Ohm safety resistors. Those were both defective. That was not directly visible on the resistors as shown in this picture:

As a precaution I removed and replaced four of those resistors. Then it showed that at least one had been a bit to warm.

New resistors installed

And the CD is working again!

To see whether the laser current is still within specifications, I looked up the procedure in the service manual. The voltage should be measured over R16, which is a SMD type resistor.

The voltage was perfectly within specs, so no need for adjustment.

31 comments on “B&O Beosystem 2500 (type 2606): CD not recognized

  1. Hi Mark, thanks for your support to all. It helped me a lot with understanding the technique of the cd mechanisms.
    Currently I am servicing a Beocenter 2500 (cassette, cs load and doors are working now). Unfortunately I do not get the cd to work properly. Before I took all apart, it did work. However, all it does now is spinning the cd very fast and the laser head is moving to the most outside position and stays there. Until I do unplug the mains or push the “load” key.

    Any idea where to look or what causes this behavior?

    • Hi Bart,

      Thank you for your reaction!
      For your Beocenter trouble shooting can differ a lot because there are different kind of cd mechanisms out there. The one I was referring to, is a CDM4 transport (with a swingarm, the laser moves radially across the cd).
      There are also linear tracking CDMs, most likely a special kind of CDM12.
      With the first cd transport the assembly is controlled by the PCB behind the right sliding glass door. With the CDM12, it’s all controlled by the PCB behind the CDM mechanism.
      I am able to fault find much more easily with the CDM4 transport than with the more complex CDM12. I also had bad luck with “new” replacement CDM12 transports. most of those had a replacement laser, but with probably used spindle and tracking motors.

      The symptoms you describe are most likely due to a tracking/focus issue. The transport does detect the CD (can also be done by a separate system), but can’t locate the lead-in/TOC tracks.
      With the CDM4 transport I would start looking for bad capacitors on the CD PCB, also bad solderjoints and defect resistors.
      First of all start with checking the steps I described in the startup sequence of cd players in general.

      Hope this helps you a bit in fault finding.

  2. Hi Mark
    thank you for your work

    I have a 30 years old BEOLAB 2500 and the CD player doesnt read the CDs anymore (actually it works sometimes but not often) – the CD keeps on going backwards very fast and dont stop – thanks for your help and support – Lionel

    • Hi Lionel,
      Too bad that your 2500’s cd player is not working anymore.
      Rotating backwards is a common symptom to many faults in a Philips based cd-player.
      Tracking and spindle motor control get lost and result in this behavior.
      It’s hard to tell what is causing it. Step by step trouble shooting is what I usually do, but that requires some experience.


  3. Hello,
    I have this Beosystem 2500. Here in my system every thing works perfect but when I play the CD there is a tik tik or continuous cracking sound coming out. Every other operation of the CD works perfectly fine (Lid opening closing, rotation of CD or change of track fwd or rev etc) Please help me how to resolve this.
    Many Thanks & Regards,

    • Hi Atif,
      Since the control of the player is working fine, but the output is somewhat distorted, the problem lies most likely in the circuit with the digital to audio converter and/or digital filter/oversampling. This is happening a lot with the CDM4/CDM9 circuits with the TDA1541 DAC and SAA7220 digital filter.
      First of all check if the voltages are correct of those circuits.
      When those are within margins, you will probably need an oscilloscope to track the digital signals and see if they are as they should be.

      Hope this helps you in any way.

  4. Hello Mark, have the same problem.
    So many thanks for putting this available.
    Could you advise on which resistors to order ?
    It seems to my non-expert eye that the ones you put it are not the same.
    But to be clear, I’m a novice on this.
    Kind regards

    • Hi Filip,
      Color and appearance can differ depending on the brand/model/year of production.
      In the schematics a triangle with an exclamation mark is indicating that there is something special with these resistors, usually that these should be so called fusible resistors.
      These kind of resistors will break the circuit when high current flows though them and reduce the change to catch on fire.
      In the service manual it only specifies the following: 1Ohm 10% 0.3W. The old resistor did get pretty hot, so that didn’t appear to be a fusible resistor.
      To be on the safe side, I would go with a .3 or .5W fusible resistor of 1 Ohm. For testing you can start by putting in a regular .25W 1 Ohm and monitor the resistors and replace them with fusible ones later on. If they start to smell, glow or burn, you would have to dig deeper what is causing that… 🙂
      Good luck!


  5. Hi,
    I have had our family 2500 in storage for many years. I do not have the remote or any cables accept a spare power lead. I have plugged in and there is a light, doors open and the load button works on cd. However, that is it there is just a red dot in the corner of the display. It’s like it is stuck in stand by mode? Can you assist at all? Thank you Terry

    • Hi Terry,
      I’ve seen such symptoms once on a beosystem/beocenter. Don’t know what type and/or revision it was (there could be several).
      With that one incident I wasn’t able to locate the cause of the “stuck in standby”, which is exactly how I have called it. In my case you could operate the devices for a while, get it in/out of standby with keys/hand gesture or remote. Only when the device is in standby for a few minutes, it locks up.

      In your case it could perhaps be something simple as a lock function. From what I remember is that some devices had some sort of lock (or hotel/motel) function.
      I’m not sure if yours has one too and if you need the remote for it (I would expect so).
      Hope this is something you can work with.

      Kind regards,

      • Thank you for your reply Mark.
        I don’t have a remote sadly. Real shame as my son would love to use it 🙂 very best, Terry

  6. Hi Mark and thanks for your help.

    My beosund overture CD has a strange behaviour, detect the CD, spindles Ok, but I only hear the music intermitently.
    I have cleaned the lens but nothing improved.
    Any ideas where to look for?
    Thanks so much

    • Hi Ignacio,
      These symptoms can have several root causes. The way I would start troubleshooting these kinds of errors is to hook the CD-player output to an oscilloscope and see how the distortion is displayed. I have seen defects in laser/pickup/calibration, defective DAC’s or oversampling chips, bad soldering, low or unstable voltage fromm the power supply, etc.


  7. Hi Mark,
    Thank you for sharing this info. I have the same problem, and I want to try to replicate your procedure.
    According to the manual, PCB 8 controls the CD servo. Should I access it from the back by removing the rear cover?
    Or is it easier if I remove the glass door and the front panel? It’s going to be my first attempt, so I would appreciate any advice you can give regarding the disassembly.

    • Hi Phil Jeon,

      To access PCB 8, you will have to remove the glass panel and the glossy panel behind it. The glossy panel is held in place with clips, you can pry it loose with a spudger or other plastic tool that is wide and flat. I would not recommend using something small like a screwdriver.
      Also have a look at the service manual for this type. Make sure you have the correct one and the correct pages within the service manual, because there have been a lot of different types/versions around.

      Good luck!

      • Hi Mark,
        I got to the PCB 8 without too much difficulty, thanks to your advice. Problem is, it looks completely different from your picture.
        I have uploaded the pictures of my PCB 8 on my onedrive and here’s the link: https://1drv.ms/u/s!Agy3JOZICG-bkWGqdKB_3V-Oj7r6?e=sgbSXf
        I don’t see any resistors on my PCB and on the other side, a lot more of those tiny components with numbers on them. What are they?
        Even though your system is type 2606 and my system is type 2608, the service manual is for both the types. Could they have made that much change on PCB 8?
        Can you spot resistors 71, 72 and 112, 113?

      • Hi Phil,
        It seems like your system has a different CD-transport. The system that I was working on had a Philips CDM-4 (Swing arm, laser moves in an arc). I thing that your system has a Philips CDM-12.x transport (linear drive, laser moves in a straight line).
        Those systems have their controller board on the back of the CD transport. (These are shown as one piece, CD-transport + controller board) in the service manuals)

        I have been working on a few of those versions of these beocenters/beosystems. In a few cases I eventually gave up on those because a “new” (China?) laser did not solve the issue. Could be because the laser was incompatible or just a defect laser that was sold as “new”. The CDM-12 has several version (CDM-12.xx), not every version is interchangable. Also some are sold as CDM-12.1 but are really CDM-12.4, which are not 100% identical. It could work, but could very wel not work. The alignment of the pins on the laser sensor (in a circle or rectangular) is sometimes a sign that it’s a different version.

        I hope that your system has a solvable problem. First is to find the right service manuals that reflects the system you have.


      • Thank you for your prompt and detailed response. Very kind of you.
        I was about giving up on this, but I did google search for ‘beocenter 2300 PCB 8’ and found one on sale on ebay for 12 euro.
        The picture looks exactly the same as my PCB, and it says good working condition. Hopefully the unit had other problems, not CD. ^^
        It will take about 3 weeks to be shipped from Germany to S. Korea, but I will let you know if it’s a happy ending!!

  8. Hi.
    My B&O 2500 CD and cassette do not work.
    The CD doesn’t spin the same with the cassette. I did not use it for few years and it was stored in a wardrobe in my house. Please advise.

    • Hi Sam,
      Have you tried cleaning the cd’s laser lens with a cotton tip and a bit of alcohol? When storred for a long time dust is most cases the issue.
      For the cassette deck, it’s probably the rubber belts that are sticky or sometimes dried out. In most cases these rubber belts turn into a sticky gummy type of mess.
      After a lot of cleaning with alcohol and degreaser you need to install a new set of belts. A service manual would be handy to see where each belt should be installed.
      It’s a lot of work and the cassette unit needs to be dissassembled partly (after taken it out of the system).
      I would recommend to do that only if you have a lot of experience in these kind of repairs.

      I see many users who leave the cassette unit as is and only fix the cd.

  9. Hello.
    In my case the CD starts but after a few laps it simply stops, the CD turns for 3 or 4 times then it stops. If I press play it repeats the process and stops again. Can you help me please?

    • Hi Ivo,
      That could be a lot of things really. Check which of the sequential steps are executed. So laser travel to the inside of the CD, focus, tracking, etc.
      Have you cleaned the lens with a cotton tip and a bit of alcohol?

      Hope this gives some insights in what’s going on.

      Kind regards,

  10. Hi Mark
    I found your guide very useful to identify the problem of my Denon CD Player UCD-F88 (part of the UPA-F880 system) spindle motor that doesn’t start running.
    In the first place I tought it was an error from some sensor, since the player had a misaligned feed and frame, so the door won’t close correctly, and i had to disassemble and reassemble the unit. Then I had a problem with a sliding feed motor belt, that was been probably overheated and deformed by the motor’s spinning in it, since the feed slot was blocked.
    Now, my problem is that a service manual for this unit seems to be unavailable, and, despite of the really clear main board ID for every component, jumper and voltage, I can’t understand how to check the laser lead in return and motor input voltage (on its connector is 0)…
    Could you help in any way?

    • Hi Luigi,

      For what I can tell based on a Google search for that cd player, it’s pretty different in comparison with the B&O cd system.
      I think the Denon is built on a Sony assembly, don’t know what type it is exactly. KSS213 or KSS240, I would guess.
      When you move the laser assembly to the middel of the slide and then power up the player, does it then move towards the spindle motor?
      If that works, then you can be sure the tracking motor circuit is working.
      Next is to check the spindle motor, but with most Sony systems the spindle motor only starts after a cd is “seen” by the laser. So laser control, focus and laser pickup signals should work.

      Kind regards,

  11. My beosound 2500, while playing a CD there is a poping sound/ cracking sound. Plz help how to resolve it. Thanks

    • Hi Atif,
      It’s very difficult to pinpoint what is causing this sound from a distance. Does it happens all the time? Or only when the beosound is cold? What have you tried to resolve the issue? Does the CD turn freely when the CD door is closed? You can try if the problem gets worse or not when you lay down the beosound on its back or tilt it that way.

      Kind regards,

      • Hi Mark,
        Thanks for the reply.

        Does it happens all the time?

        Or only when the beosound is cold?
        NO… same response all the time.

        What have you tried to resolve the issue? Show it with one mechanic… but he is not a B&O expert… but he tried some flukes but nothing happend.

        Does the CD turn freely when the CD door is closed?
        Every thing works perfect except this cracking sound… Recognize CD, change tracks…. I mean every thing works fine but the POPING or CRACKING SOUND

        You can try if the problem gets worse or not when you lay down the beosound on its back or tilt it that way.
        I have tried but no change same problem…

        Plz help how to fix this… or is there any specific laser lens no. for this CD player? so we can change the lens or any thing else?

        Many Thanks & Regards,

      • Hi,

        Those B&O systems have different cd player systems installed over time. The older (better) ones were the CDM4 laser units (swing arm) with TDA1541A DAC board that is located on the right side of the system (behind the shiny black cover).
        That is the one that is shown here in the images. The other one is a CDM12 kind of laser unit with a control PCB at the back of the laser unit. These are not so great to repair.
        When you have the version with the CDM4, then it’s most likely never the laser unit. These are extremely reliable. The crackling/poping noise could be related to the DAC or Oversampling chip, or its power supply.
        Check the -15V and -5V signals to the TDA1541A. Are they stable and have little ripple on them?
        If you have an oscilloscope available, play a test CD with pure sine wave, 1kHz is commonly used. View this on the scope and look at the shape of the crackling/poping noise. That could point you to the cause of the problem.
        With the CDM12, you never know what is causing the issue. Sometimes you could replace the complete laser assembly with laser and motors, but it’s hard to get one that is actually new. I see lots of reused motors and “new” lasers fitted into them… 🙁

        Hope this helps you a bit.
        Kind regards,

  12. Hi Taraus25,

    Sorry for the delay in my reaction. Somehow I didn’t get a notification.
    In most cd-players the spindle motor wil only start if the laser light is reflected on the disc and detected by the pickup.
    I have never seen a damaged spindle motor before that is completely dead, so to me that’s highly unlikely. In cases where the spindle motor is defect is that it does not run fast enough or is unstable due to worn bearing.
    The following sequence of steps is the best way to troubleshoot:
    1. Check if laser tracking servo moves the laser to the center of the CD
    2. Check if laser is emitting
    3. Check if focus lens is moving
    4. Check the voltage from the spindle motor driver to the motor

    If step 4 fails, it might also be the laser current that needs adjustment (Only with CDM swingarms, not with CDM12 in later BeoSounds.)
    The service manual also states that the laser current needs adjustment after replacing the laser. Remember that for the best adjustments you need a reference disc that meets Red Book specifications.

    Kind regards, Mark

  13. My beosound 2500 after changing the laser still could not work. Understand the issue is not just the laser lens but the spindle motor could not spin the disc . Does this mean the spindle motor is damaged and need replacement ?

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