Beocord 9000 – keypad not responding

[baek47]

I bought a Beocord 9000 and did various repair – but it is not responding at all activating buttons on the keypad panel.

I powers up and I and there is light in the dispay + cassette drawer.
All belts are changed and capstan is running.
All leafspring concats looks good.

I can meassure the -24, 24, 32, 13 volts on the board 6.
I can also meassure 6.2 and 5 volts on the board 1 – didnt check all testpoints here.

But looking at P21 wire 3 in the servicemanual it says 5.5 Vp and shows some kind of pulse or AC curve.
The P21 wire 3 only feed the IC1 (input/output expander) pin 38 texted 50/60hz.

Meassuring P21 wire 3 I have:
1,6v DC and 0,7v AC connected to the board 1
2,7 DC and 1,7v AC no load
My very bad usb oscilloscope shows nothing….

Could this be my problem?

Best regards baek47

[baek47]

I also recapped all brown/orange ROE capacitors.
I replace the 4.7v zener before the P21 wire 3.

[baek47]

I also recapped all brown/orange ROE capacitors.
I replaced the 4.7v zener before the P21 wire 3.

[baek47]

I tested the P21 wire 3 with an oscilloscope. There is 5.5 v ac according to the servicemanual. Good – but the problem is still there….

Changed some transistors…no change.
Checked thoroghly the keypad is working.
Changed more capacitors…no change.
Resoldered a number of multiplugs….no change.
Took the motor apart again….no change.
Tested thoroughly all contacts on motor….

The symptoms are:
When i connect to power, the capstan starts running…
I can not put it into StandBy…
Keypad not responding whatsoever…with or without cassette inserted…

And…….when connected to power the lamps “Fe”, “Metal” and “Rec open” are lit, the “Cr” and “No store” are not  – no matter whether a cassette is inserted or not..

Anybody have an idea where to look?

Br baek47

[Dillen]

Some versions have a fuse on the display board. Have you checked?

Martin

[baek47]

Hi Martin
Yes, it is good and the IC1-3 are getting 4,8 v.
I also checked that I have continuity on the display board when activating buttons on the keypad.

Since my my last post I changed all transistors (and caps) on the “display board 1” and the “digital/analog converter board 11” – no change except that the “rec.cal.” on the display board isnt lit anymore. And resoldered almost all joints as well….

By the way, my model is the first, below 2831001.

Next I will go through the Osc. board 13 and Rec/ampl. board 3….but advices are welcome

Regards Torben

[Author]

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