More CD-Player issues

After the amplifier is working it is time to check the CD-Player. Unfortunately it was not all the time working. Sometimes the CD was spinning faster and faster, the controller was unable to read the TOC returned an error.

It was working better when the Decoder Panel was in a vertical position. So I thought it might be a loose contact. I checked all the solder terminals and refreshed some. In addition I checked the cables if there is any loose contact but they are working fine.

First I checked if there is a signal according to the service manual for the two TDAs which there is no signal on the output pin 22. The DEEMPH signal is fine and I assumed there might be something wrong with the mute circuit or the OpAmps. To ignore the circuit I removed a bridge right after Pin22 of the TDA 6304. Afterwards the troubles began – nothing was working anymore – the CD Player always returns an error.

In the next step I followed the service manual measuring the functions of the Decoder Panel. Until the measurement of the DADE signal everything was fine and within the specs. In the meantime it got worse – the CD head is moving uncontrolled up and down..

I checked all the voltages of the IC on the Decode Panel again and tried to replace the SAA70x0 ICs step by step since I have almost all of them on stock (except SAA7000). Also without success.

Now I am running out of ideas. Since all voltages are fine I might try to replace the Decoder Panel and/or the C.D.M.2 with one of the other machines at least to be able to check where the issue is located.

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