The Workbench

Re: Periodic faulty CD on Beosound 3000....

kumse — Wed, 23 Feb 2011 18:25:27 GMT

Well

I have done some control measurements. Controlling the supply voltages for the circuits on the CD Pro2 board. They seems okay.

I returned to the issue, that the spindle motor did not rotate, even that it got the service command "TM 63", if i rotate the cd with the fingers, im able to hear some acoustic noise.
I can se a wierd triangular waveform at the terminals of the spindle motor:

Notice the frequency, ~176khz, wich is noted as the upper frequency limit of the TDA7073 driver. Maybee something is oscillating?

I cant see this waveform at the input of the driverstage!

Checking the other output from the driver stage (wich drives the focus) seems to work. It tries to focus, and the laser moves nicely back and forth

I have also investigated the communication from the main µProcessor board to the cd mechanism. But it seems okay in both directions.

It could be nice with some input guys!

Thanks in advance

//Thomas

Re: Periodic faulty CD on Beosound 3000....

kumse — Tue, 22 Feb 2011 18:27:19 GMT

Hello guys

After further investigation, im a bit confused. I can not find the resistor to measure the laser current 80R3121.

I have tried to operate the unit in service mode. When i try to play cd, it plays nice with sound for some time and give me "Error 37" : The manual says "Selection error" with no further explanation. Sometimes it also gives me "Error 3" : Radial error.

The wierd thing is though, that when i try to force it to spin the turntable motor, it says turntable motor "on", but it does not spin.
When i try to move the laser to the outermost position, it does not.

Hopes someone have some experience on this

Regards

Periodic faulty CD on Beosound 3000....

kumse — Mon, 21 Feb 2011 15:21:28 GMT

Hello out there

My lovely beosound 3000 have started doing trouble...

When i try to load a cd, the clamp goes down, and opens a few seconds after. The cd does not spin. Sometimes it turns ~1mm.

Sometimes it suddenly reads the cd, and plays... it can play for like half an hour, but then suddenly stop...

I have just buyed the service manual.

http://dl.dropbox.com/u/2862390/Beosound%203000%20service%20manual.pdf

My plan is to check the laser current by measuring the voltage on 80R3121 according to page 62.

Afterwards turn it into service mode and check for errors.

Right now, im a bit confused, wether its the spindle motor, or a focus error.

I have tried with success to change the laser on a beosound overture, but the cd mechanism was the older cd pro, wich only deny to spin up if it failed to focus. But my beosound 3000 just opens the clamp ?

Thanks in advance!