Capacitors

Electrolytic capacitors lose their properties with the hours of operation, but also with the simple course of time. When I restore a chess computer that is more than 20 years old, I usually check them all. Because they often have to be unsoldered, and since they are not expensive components, in some cases I replace them all. It is by no means essential: only on a few occasions have I found bad capacitors in a chess computer. Something quite different happens in circuits with harsher conditions (TV, switching power supplies, etc.).

This is the list of aluminium capacitors in the SciSys Mark V:

• Cmem = 10uF/16V

• C3 = 1uF/50V

• C5 = 2200uF/16V

• C5b = 1000uF/16V

• C6 = 470uF/10V

• C7 = 4,7uF/25V

• C8 = 47uF/25V

• C9 = 4,7uF/25V

• C10 = 470uF/25V

• C11 = 4,7uF/50V

• C13 = 1uF/50V

Since nowadays electrolytic capacitors are smaller (at equal capacitance and voltage), you can replace C5 with 3300uF/16V and not install C5b, as both are connected in parallel. Also, it seems that this was the original idea, as there is only room for one on the component side.