amr wrote:

I have a Beocenter 8000 with the same problem. Changed both resistors and a transistor that messured out of range. Now the CD spins up and keeps spining at a speed near light:), after 3-4seconds the lid opens. Before doing any "repairs" the cd did maybe move for 3/4 of a round. Anybody who have a clue?   

You probably shouldn't believe anything I say 😁, but I seem to remember that this happens when the focus offset adjustment is way off. DON'T touch the the other trimmer - laser current - though, if you know the CD has worked earlier with its current setting!

I suggest you replace capacitors BEFORE readjusting anything. An adjustment won't just go out by itself, it's far more likely to be one or more dried out capacitors. Could also be a cracked solder somewhere, especially in the voltage regulator areas.
Depending on the deck version capacitor kits are readily available for the servo board (or one can be put together).

Martin

I dont think it has do with the focus offset. Today I took a look at the Beocenter again and I messured the current to the cd motor. -7,4V, which means that the cd spins the wrong way?😕 Am I on to anything now?:)

Ok, in the beginning you see the circuit plan for the motor. It's a dc motor, usually it works with around 3-5V. If you measure negative voltages, then something is wrong... rotating in the wrong direction.

This BC8000 board shown above is almost identical to the CD6500/7000 controller board.

Let's check some things first: The circuit plan is wrong, TR6125 is a BC328-25, not a BC338.

Replace first: 

TR6124=BC338-25

TR6125=BC328-25

R3212 + R3213 = 10 Ohm

C2138, C2140 = 220uF 16V

C2103=33 or better 47uF 16V, axial, MUST be blue PHILIPS or blue BC, other caps will cause problems!

C2104, C2107 = 47uF or better 100uF 16V

Replace ALL electrolyt caps, replace the bipolar C2159 1,5uF cap by a Wima MKS-2. This cap can fail and has already failed several times! 

Remove the motor plug and measure: R3212: +9.5V, R3213: -9.5V

Pin 7 of the IC6103=NJM4560 must be the same voltage measurement like the output pin for the motor. Check it.

Pin 8 of the chip= +9.5V, pin 4 = -9.5V. If one of these powersupply voltages is missing, a savety resister is burnt (R3210 + R3211 =  1 Ohm)

The signal MCES means MotorControlEnableSignal... simple Motor_On. It is a pulse wide modulated signal (140us, 5-50% varation). Check it. checked with a dc multimeter (this is just wrong, but try it...), it must be active around 2.5V

But.... i'm pretty sure, that the focus DOES NOT WORK, probably another resistor or chip is burnt. Check IC6104=L272. Pin 16=-9.5V, Pin 2=+9.5V

Ground is chassis frame.

Thank you for your help, I will get to work

:)