Beogram 4002 (5503): Exchanging all Electrolytic Capacitors

After completing most mechanical adjustments it was time to restore the electronics of the Beogram 4002 (5503) that I am currently restoring. It is always a good idea to replace all electrolytic capacitors since their electrolytes often leak out or simply dry out. I use only 105C grade Japanese replacement capacitors to maximize the longevity of my restorations. In particular Tantalum based electrolytic need to go since they can die a fiery death if they short circuit due to electrolyte loss, which can leave black craters on the circuitboard. And that would be very un-Beolovely! So here we go:

My favorite part is always replacing the big old reservoir and motor coupling and phase capacitors. Here is an impression of the solder terminal side of the original setup.

The two capacitors on the right are the motor caps and the two bigger ones on the left are the reservoir capacitance of the 4002 power supply.

This shows the back side towards the AC motor:

Modern capacitors are smaller and this allows to clean up this set-up by using a custom designed 3D printed capacitor adapter that neatly holds the new capacitors:

This assembly is available to other enthusiasts. Just send me an email if you are interested.

Here is an impression after installing it:

and from the back:

The adapter fits snugly under the original holding strap, which holds the assembly firmly in place. And note the dedicated grooves that hold the wires orderly in place! Very Beolovely!!

On to the exchange of all capacitors on the main board. This shows the original set-up. The orange cans are often cracked or leaky. The small orange dots are the Tantalum capacitors:

There are also two Tantalum caps on the solder side of this board:

This shows the board after replacing all the caps:

and on the solder side:

There are a couple of electrolytic caps on the secondary boards of the 4002 (5503) such as this cap on the sensor board:

Of course it also had to go:

there is one more on the output board that is located under the keypad. I will get to that one once I exchange the RPM indicator light bulbs with custom designed SMD LED boards. For that I will have to pop out the RPM indicator panel, which in turn will give me access to the bolt that holds the keypad down. Stay tuned!