CD player with Philips stuff. Power up problem.

[Agent327]

Hello all..

I am trying to fix a Consonance Opera Reference CD-2.2 cd player with a power up problem.

Symptoms after power up are:
- Sledge motor keeps on running towards outer diameter of disk, away from the position switch.
- Sometimes, if I try many times it keeps on running towards inner diameter of disk.
- Sometimes it closes the cd tray.
- It makes no difference if CD tray is in or out, CD or no CD.
- It makes no difference if I detach the data cable from the microcontroller. I see with the scope communication on the data lines.
- Display says: No disk.

5V and 9V to the servo board are ok.
CD mechanism is Philips VAM1202/12
Logic board made by Hegel, with SAA7327 servo processor, TDA7073A drivers and TDA1300 amplifiers.

What shall I do ?

Any ideas would be much apreciated.

[Mooly]

Extremely difficult without circuit. Is it your own -- symptoms like this can be typical of spillage that isn't always obvious. You need to identify and measure all supplies -- not easy-- look up the data sheets for all the IC's and use that to help identify. If the front display makes sense that's a good sign. Any safety resistors in any rails gone high. What type of PSU is it ? SMPSU or linear ?
The fact the sled runs the wrong way at power up points perhaps to a supply problem somewhere. You need a circuit to check ALL the inputs to the various system control IC's.
Sounds a bit chewy

[Agent327]

Hi Mooly,

Thanks for your advice.
I was hoping someone would yell: Replace the VAM. Guaranteed succes!

This is my first time on a CD player.
It belongs to a friend of mine. He has had problems before with this player and service took a very looooooong time.
What do you mean by spillage? Let out blue smoke?
I have the datasheets and will draw a schematic soon. A lot of passive components and tracks swapping from one side of the pcb to the other. I will probe some more on various chips. Power supplies are linear and look ok on the scope.

I will chew on it and let you know.

[Mooly]

Hi,
I asked if it was your own because I have seen countless "faults" ( on TV VCR etc ) caused by liquid damage. Coffee, Pepsi, cat wee seen it all, and weird faults are often down to things like this. Or has it been dropped ? -- cracked print etc. The really strange thing is even very experienced techs don't always spot things like this, it can be very subtle and hard to see. Less likely is a cap " modern solid type electroylitcs" if it has any can leak a corrosive electroylite causing a green verdigris on print and legs. Look for any change in colour around bright component legs, spilage tends to remove the shine.
The start up routine should be fairly simple, the system control IC will look to see if the various inputs from things like the drawer switch and sled end stop switch are correct. If they are not, the appropriate motors should be powered in the correct direction to bring things to the normal position. As this is doing weird things it suggests something much more fundamental that is wrong.
Good luck with it

[Agent327]

Hi Mooly,

Oh yes cat wee. Cats are evil, they tear speaker drivers too.
I prefer dogs although being mono they sound more real than the stereo. ? !

This player is very well kept, no visible damage and no contamination of any kind.
This weekend I have time.

Thanks for your input.