Mark-sf
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Are you certain it was R201 3.3K ohms that was burned? I ask because that is a series input resister to the power amp IC and i can’t see it getting the current to “blow” it. If that is the resister, could it have been cracked instead? As to the noise can you describe its character. Can you check if you are getting a DC voltage on the output with the speakers disconnected?
Those were power darlington transistors. You can use BDX33A and BDX34A to replace them.
I would check the 12v supply. You may have bad caps at C3 or C4. Make sure you have a clean 12v at the solenoid. TR6 regulates the voltage to 5v for the motor so it would not cause this issue. There may be 120Hz noise on the 12v line.
Based upon Beolover’s sample, that separation was caused by force. Note that there is thin film residue to the old bond indicating that a shear force will likely be more successful than heat softening. This would call for a non-marring mallet with the platter supported thru the center hole. You could also try a .1mm stainless steel spudger to work around the edge to break the bond.
I would not try as the two pieces are bonded. Applying heat to relax the bond would damage the ribs.
Christian, I’m afraid the 8002 had a different bearing yet again as it was a different drive system.
I believe the confusion is due to the 4002 having two different bearings. The earlier 5503 types had the platter from the 4000 which had a ball and thrust pad. Yours is the later one which had a lighter but larger black subplatter and only used a centered point. In any case, there does not appear to be anything missing.
Are you sure about the models you are comparing? The CX100 is a passive speaker and the 4000 is active.
I would check the 7V power supply section around TR19 and C10. If the fuse that was bad was T1A for the 5v supply there may be and issue with IC4 circuit or its zener.
I don’t know what you mean by “servo noise”. If you mean 120hz buzz then it’s likely a power supply cap problem. As for the 45 sod are you seeing a variable freq on pin 1?
If you have access to an oscilloscope you should find a 500Hz sine wave on P1 of the motor connector when the speed is set to 33. It’s possible that the motor control chip has been damaged. Check the schematic available at https://beomanuals.com/manuals/Beogram/Beogram%202402/Beogram_2402-Schematics.pdf. While its a different model it uses the same motor control circuit.
Your problem is not likely an electronic one but a mechanical one. There is a muting switch under the tonearm that is activated by the arm movement. It likelly needs its contacts cleaned. The service manaul is at https://beomanuals.com/manuals/Beocenter/Beocenter%207700/Beocenter_7700-Service_Manual.pdf. The part is 1567 in the parts list but the diagram marks it as 1557. You open it by removing screws in the rear and it hinges from the front.
I would not hold my breath given that B&O is out of the turntable business. You might try contacting Rudy over at https://beolover.blogspot.com/2015/01/beogram-40024004-apple-remote-controls.html and see if you can convince him to come up with an 800x version. I have the one for my 4004.
Your BeoSound stage manages remote commands only via BT, HDMI or Ethernet and your 8002 needs a wired datalink signal coming from a Master system. From my knowledge your BeoSound does not have a source Master system interface nor do those ML and MCL components. The Master system is what decodes the output of your Beoremote One IR commands into the datalink control signals the 8002 receives via its DIN connector.
The other issue you have is that you need to get the DL signal into a Master system component which do not pass through your phono preamp as they have their own DIN signal pins.
Excellent work. Having done something similar for the Beogram 4002/4 series and GRado Signature carts(which I sold many in the 80’s), I fully appreciate the time and effort. I am confused by your statement that the cartridge is sealed in the shell as from your pictures you have omitted the cartridge body and its 4 pins that plug into the arm and are only displaying the SP stylus shell. In my case I re-wired the tonearm and built a special socket receptor for the pins. I don’t see any cartridge pins in your pics, hence the question.
In the bottom cover there are two holes that adjust the set down point for 7” and 12” records. It is easiest to place it on a stand or supports so that you can watch the arm without having to constantly flip it. If your bottom does not have the holes then you will need to remove the 4 corner screws and remove it first. These eccentrics should be marked and are in the from of the cam gear.
That model has many electrolytic caps that by now have started to fail. That is usually the cause of it spinning backwards. You should start by replacing them in the power supply and motor/coil section. Once you’ve confirmed correct and stable voltages then you can see if there are other issues.
I would continue to check for the proper power supply voltages to the different modules. Even though all the fuses are fine, a unit this old can have failed or failing electrolytic capacitors. I believe the tuner section has at least one rail dedicated to it (12v) and you also will need +-33 to the chip power amps.
