How do you work a hornby-dublo ED3 junction signal upper quadrant?

Answer 1

There are 3 connections on side A, and 2 connections on side B. The center connection on side A is the common ground for all of them. Applying a voltage of about 12 to 14 volts (AC or DC) briefly on the end connectors of side A will operate one of the two semaphores, and applying such a voltage to the connectors on side B will operate the other, in each case to raise or lower the arm. It is important to note that applying a voltage to any connector for a length of time, more than a second or so, will cause damage to the solenoids that operate the mechanisms. These signals are designed to "kick" up or down with a momentary voltage only. Using an AC power supply may cause a buzz when applied, DC is usually quieter, but both will work. Maximum current can be high, so operating more than one of these at the same time might prove more than some power supplies can do. One at a time, almost any 12-14 volt supply will work. Let me repeat that continuous voltage will damage the solenoids and they are not repairable.