Beocenter 9500 CD doesn´t play a sound (only the CD). Tuner and cassette are ok

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69er Posted: Mon, Jul 26 2021 2:55 PM

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Higuys,

i have currently two Beocenter 9500 on the bench (one has an open thread already - see other posts).

Now my second one is working fine - tape, doors, cd (new caps). But, the CD plays, but there is no sound. All toher sources are ok.

Is it just a cable connector issue or some specific cap whic is responsible for te CD sound?

Best regards

69er  

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Spassmaker replied on Tue, Jul 27 2021 11:10 AM

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Hi69er

You say CD is playing, is the timeindicator running and the tracknumber blinking?

Did you recap the servoboard, if yes recheck the wire connection between Laser and Servoboard and have a close look for the flat wire conection, is it sticked in complete? is the plug locked?

After that you can check the connection from

Decoder board No.:31

P13 - 1 (AF right) to Tonecontrol/ Input board 53    P71 - 3

P13 - 3 (AF left) o Tonecontrol/ Input board 53       P70 - 7

On these Plugs you could hook in an AF generator to check if the AF line is working.

Could also be that the AF MUTE LINE is activaated in CD Mode of some course

On Tonecontrol / Input board No.;  53

P 71 - 7 should be - 10 Volt when not muted, +5 Volt when muted.

Signal comes from Amplifier bord No.: 60

P 84 - 6 via TR 21 activated by IC 2 (4094)

Good luck

Christian

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69er replied on Tue, Jul 27 2021 2:11 PM

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Hi Christian,

yes, the time indicator is running - i can also switch beween the tracks (tracknumber is blinking).

My first guess is really a connector issue, but i haven´t seen any disconnection so far.

If it is the mute thing (didin´t even know, that single sources could be muted) -  how can i change that?

Best regards

69er

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Spassmaker replied on Tue, Jul 27 2021 6:18 PM

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On Tonecontrol / Input board No.;  53

P 71 - 7 should be - 10 Volt when not muted, +5 Volt when muted.

Signal comes from Amplifier bord No.: 60

P 84 - 6 via TR 21 activated by IC 2 (4094)

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69er replied on Tue, Jul 27 2021 11:16 PM

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Hi Christian,

p71-7 has -10v

So no mute.

p84-6 has also 10v 

p84-5 has 5 (aux mute)

I checked all connectors, can’t find an issue.

now when listening, sometimes there’s a crack which I could hear. Just a small noise every 30-40 seconds

🧐

69er

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Spassmaker replied on Wed, Jul 28 2021 10:51 AM

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Hi

I don't really know if the AUX mute should be muted, try to activate AUX and measure P84 - 5 if it goes to -10 V.

Connect a source to AUX and check if this way works.

Regarding to the service manual it should be muted when switched to CD / TAPE / TUNER

On these two connections from Decoder BOard 31

P13 - 1 (AF right) to Tonecontrol/ Input board 53    P71 - 3

P13 - 3 (AF left) o Tonecontrol/ Input board 53       P70 - 7

you could measure the AF from the CD with a usual DMM on AC should be around 150 to 300mV maybe more depending on the music on the CD. Lot of bass is recommended. It's far the same if you measure your headphone jack on your mobile.

If you could measure the AF then we are a step forward, if not then you have to check your CD Boards again.

BTW it is very uncommon that only the CD does not work on both channels because all audio switches for the different signals are together in one IC.

Still good luck

Christian