BeoCenter 9000 CD Fault

Is your Bang and Olufsen BeoCenter 9000 refusing to play CDs? Does the door reopen after loading or take too long finding the tracks? If so there may be a simple way to fix it.

Christmas lunchtime and the trusty BeoCenter 9000’s CD refused to play Dianna Krall’s Christmas Songs so I’m in the doghouse again. The 9000’s CD player had been temperamental for a while and a simple Bluetooth interface had been an easier option but never sounded as good as the CD. The fault appeared intermittent with certain CDs just popping the lid open or taking ages to recognise the tracks. Cleaning the CD player’s lens with alcohol and a cotton bud did not improve the fault.

A quick Google search suggested an electrolytic capacitor the most likely culprit on the Beoworld forum – BeoCenter 9000 CD Problem.  “Replace the C2103 capacitor on the servo board” — an easy fix they say… Well yes and no, it took me a couple of hours but it was worth it in the end.

Warning: Unplug the power lead and don’t attempt to operate your BeoCenter with the top cover open!

The 9000 is a bit of a beast and needs a large area to service it. The secret to opening the BeoCenter is a Youtube video away, see – Bang & Olufsen Beocenter 9000 Repair. But take care! My BeoCenter’s glass panels had become loose and could come crashing out if you blindly follow the helpful video. I remembered my 9000’s lower glass panel arrived detached and had just rested in place ever since so I removed it and the edging before attempting to open the top. The higher panel was also loose and also lifted free. If your panels are still partly glued in place there are two screws underneath on the left had side that when removed allow the top and bottom panels to slide to the right and lift off to be on the safe side.

The B&O designers used the car bonnet approach for servicing repairs allowing the top to hinge up from the back using a metal stay to prop it open. You will need Torx or star screwdriver bits to remove the fixings and lift the top. Unfortunately the white plastic clip holding the stay to the top had become brittle and disintegrated so had to be replaced with a 3/16 P-clip. See photo showing the clip and stay which locks in place on the right had side of the base next to the transformer. It’s worth checking the stay is secure as the top is very heavy and could come crashing down just when you are about to remove the delicate CD transport!

Removing the CD transport to access the lower circuit board needs a steady hand and patience.  Need to undo the two lower screws on the right hand side of the CD (when looking from the back). Using a magnetic screwdriver tip helps avoid the fixings disappearing into the beast. The black plastic bracket retaining the CD mount can then be removed – take care not to loose the springs and small mounts that the transport sits in.

Once clear the CD transport can be lifted away from the base to access the two grey edge connectors. See photo. Use a small screwdriver to gently lever the centre clip that hold each connector in place. You don’t need to break any circuit board to do this. Best avoid pulling the grey wires again use a small screw driver to lever the connector free each end once the centre clip is free.

Locating the Capacitor

The blue  Mullard / Philips 33µF capacitor is located on the lower PCB which is attached with 4 screws, a black edge connector and a thin flexible PCB ribbon cable. The ribbon is held in place by a white clip that can be pulled up to unlock. I replaced the axial capacitor with a 30v radial type with two 90 degree bends so the leads do not pull apart from the capacitor body.

You may read posts that say to replace all the electrolytic capacitors and buy a whole kit of capacitors. I prefer to do minimal damage and suggest checking them first with an ohms test using a simple multimeter if you don’t have a capacitance meter. On the multimeter higher resistance setting, say 20kΩ (ohms) range, check the time it takes to change resistance then reverse the leads and compare the time the other way round. For example in circuit the 47µF caps took around 4 seconds to go from a few ohms to >20k either way round – the same as a new 47µF capacitor out of circuit so no need to waste time changing them. If it changed resistance in less than a second like the blue 33µF I’d be suspicious and change it.

Reassembly is quite simple just remember to insert the ribbon cable fully into the white connector and push the locking piece back down to hold it in place. Sitting the CD transport back into the 4 springs is a bit fiddly as it slides back down into position and locks in place using the black plastic bracket.

With the top back down you can plug in and with any luck the CD will be fixed. My BeoCenter had one more trick to play – I had by mistake plugged the left and right speaker DIN plugs into the 2nd channel output sockets. It’s easy to do if your BeoCenter is up against a wall the speaker plugs are hidden unlike the input sockets which are accessed from a flap above. So while the CD played the sound was quiet and distorted. I thought I’d damaged the connectors until I tried the radio and vinyl LP sources only to find these sounded awful as well. So I swapped over the speaker plugs and the volume and quality was restored! When I get time I’ll take it apart and clean the DIN sockets. The silver contacts go black with tarnish over time especially when not in use. Note to self — the circuit shows relay contacts are also used to disconnect the speakers when headphones are plugged in so these may well need cleaning as well. Good luck!

PS 8-Jan-2024

Updated links to Beoworld forum which had since been archived.

Several readers have found the fault may return after replacing C2103, the 33µF capacitor. So here are some additional things to check.

The BeoCenter 9000 uses a Philips CDM2 mechanism and the service manual is available from Elekro Tanya – PHILIPS CDM2 CD MECHANISM Service Manual download, schematics, eeprom …

Here’s an extract from page 19 showing the laser drive circuit with the suspect C2103 electrolytic capacitor.

Philips CDM2 Laser driver with C2103

The capacitor acts as a reservoir to provide enough voltage for BC338 to power the laser LED. Notice the two current limiting resistors  3104 (18Ω – brown grey black) and 3101 (12Ω – brown red black) have warning triangles. This may indicate they are rated to blow if there’s a laser fault short circuit. So check both values using a multimeter are within 5%. Change if out of spec or if there’s any brown discolouration to the banding.

The 1KΩ preset 3106 controls the laser output. Presets can age and become intermittent due to contact tarnishing. Looking back at the photos above, the preset is the square blue sided component adjacent to the capacitor. The circuit shows the wiper reduces the resistance so if it’s tarnished and high resistance the laser drive will be too low causing malfunction much like the faulty capacitor. Check the resistance between R3105 and ground – it should measure less than 1KΩ.

Use a fine pencil to mark the wiper’s position and apply a very small amount of switch cleaner. Using a hex tool rotate the preset back and forth very slightly to ensure the wiper contact is clean – take care to return it to the pencil mark starting position so you don’t change its factory setting.

Finally check the foil connections to the laser assembly and diode assembly are clean, not tarnished and fully engaged when you reassemble. Any increased contact resistance will likely cause the CD reading errors and mistracking.

BeoCenter 9000 power rails

CDM4 Power supply

Philips CDM4 power supplies

See Elekro Tanya for CDM4 full schematics PHILIPS CDM4 D-8870-8873-8874 STEREO RADIO-RECORDER TR … – Elektrotanya