Replacing the electronic components in the BeoGram 7000

The BeoGram 7000 and its 59xx siblings are from the early 1990s, and their electrolytic capacitors have reached the end of their life. Dried out capacitors lose capacitance and let ripple through, so I replace all of them, along with the rectifier diodes. Part numbers refer to the service manual.

The control board (PCB1, 8005143), built around the COP 9421 microcomputer, has two electrolytics, C2 (470 µF 16 V) and C28 (2.2 µF 50 V). I replace them with 470 µF 50 V and 2.2 µF 50 V, and I also replace both speed trimmers, R34 for 33 rpm and R32 for 45 rpm.

On the power supply (PCB2, 8005144, or 8005154 on US types), C3 is the 1000 µF 40 V reservoir capacitor between the bridge rectifier and the 7812 regulator. The original has four legs, three of them negative, so I fit a two legged replacement with a jumper under the PCB to keep the same connections. C4 (1 µF 50 V) after the regulator is replaced too, and if the fuse has blown (T500 mA, or T700 mA on US types) I replace it along with the 7812.

The four 1N4002 rectifier diodes, D1 to D4, are replaced with Vishay SB1H100 Schottky diodes to improve the motor's stability.

The 10 nF capacitor on the drive motor's own control board (10M2) is replaced as well. It sits under the motor, which comes out of its casing to reach it.

After the electronics, the turntable is adjusted and lubricated.