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Beogram 4002: Restoration of DC Motor Video Published - Check It Out!

By popular request (really, I got quite a few emails about this!...;-), I finally completed my Beogram DC motor restoration video! It demon...

Friday, June 10, 2016

Beogram 4002 (5513): Replacing the Original Dual Main Capacitor

The current restoration of a Beogram 4002 (5513) provided me with an opportunity to further optimize my reservoir capacitor replacement part, which allows the installation of two new 105C grade Japanese capacitors in the space used for the original dual-capacitance can. Such dual capacitors do not seem to be made anymore, i.e. it is necessary to replace them with two individual capacitors. Last year I designed a 3D printed part that holds the two new capacitors, but provides a flange that allows the use of the original capacitor clamp to hold the assembly securely in place.
Here is a picture of the original capacitor. The two contacts on the front are the positive ends of the 4700u and 1000u capacitors integrated into the can:
The negative contact (for both of these capacitors) is on the back side of the can:
I redesigned my 3D part to be more sturdy, but also to be better 3D printable. My 3D design learning curve continues and I am getting much better at designing shapes that can be printed with reliable success. One thing that newcomers to the 3D printing field often fail to appreciate is gravitation, i.e. overhangs and similar structural elements are to be avoided if possible. In this case I designed the original part as two parts that one can press fit into each other, which allows to print the part in its 'natural' orientation with the capacitor cavities pointing upward. Anyway, we are getting off-topic. Here is an impression of the new part after I installed it:
The main capacitor now is held by an almost closed cylinder, which is much more sturdy than my original design. The blue 10k resistor between the hot end of the 1000u cap and ground is a bleeder resistor ensuring that the 1000u cap discharges in a reasonable amount of time when the deck is unplugged. Since the 1000u cap is normally not connected (it serves to supply the 4 Channel decoder/preamp if in stalled) it can hold a significant charge for extended periods of time. This can be dangerous when one works on the unit since there is ~30V on the cap, which can be destructive if accidental connections are made. 
This shows the assembly from the back how it fits into the original mounting clamp:
Pretty, isn't it?? This is Beolove!




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