E-Z Command
E-Z Command
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Ever wonder what is inside your Bachmann E-Z Command Control Center? Let's take a peek. And while we are at it, lets look at how Lenz managed to make this unit work along with a regular d.c. Controller. After undoing six screws, the back can be lifted off the case, revealing the bottom of the circuit board.  In additon to the labelled components, the bottom of the circuit board is littered with tiny surface mount resistors, capacitors and diodes. If you remove the screws holding the circuit board and unsolder the three wires from the speed control potentiometer, you can remove the circuit board from the top of the case. There is not much to see on the top of the circuit board, mostly LED's and membrane push button switches.  While inside the case, I traced enough of the power supply circuit to realise that a d.c. Controller connected to this circuit must supply a voltage and polarity proportional to speed and direction and in addition must supply power to operate the E-Z Command Control Center circuitry. This confirms information in the E-Z Command manual which shows a power transformer connected only to the d.c. Controller and none connected to the E-Z Command Control Center when the two are used together. It also shows why some d.c. controllers, like the Bachmann 44212, can be used with the E-Z Command Control Center while others cannot. At a future date I hope to show here just what it is that makes the 44212 different. A partial schematic of the E-Z Command Control Center circuit shows the relationship between the normal AC power inlet and the d.c. Controller connection.  What initially appears to be a full wave bridge rectifier turns out to be four half wave recifiers which allow both positive and negative supplies to be derived from either the AC power input or the tip connection of the dc Controller connection. In addition, there is an input from the ring connection of the dc Controller connection. I suspect the latter changes the voltage of both the positive and negative supplies during their non-rectified half cycles, based on the assumption that the track output of the dc controller is full wave rectified. I hope to further investigate this after obtaining a 44212 d.c. controller. Jim Banner 24 October 2005 |