Electrohome ECP Series

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The below image shows the older style focusing board, and the problematic focus resistor that was underrated on the earlier ECP sets. This resistor would overheat and drift in value, causing the focus to drift and eventually drift out of range completely. The picture below shows the original focus resistor. Later models used a larger flat or round resistor that cured the overheating problems. The below image also shows an optional 10 Meg ohm resistor in series with the original 45 Meg Ohm resistor to accommodate the newer version 07MS tubes that needed a slightly different focus voltage to operate correctly. The main focus resistor is a 45 Meg Ohm resistor. These are hard to find, and I always use three 15 Meg ohm resistors, 2 watt flameproof ones soldered together in series to replace this older resistor. Once the resistor is replaced, the repair is good for the life of the set.

Note that the top board of this two board bias/focusing board has a long connector with purple wires going to it. Make sure if you take this connector off that you insert it correctly. Installing it with one pin off will cause all sorts of havoc within the set.

The last point of note on this focusing board is the focus connectors that go to each CRT. These leads have about 5000 volts on them. The black G2 lead coming to the focus board has about 12,000 volts on it, and goes to a separate pin on this focusing board. Use caution when working in this area with the power on!