Kaiser Radio

[Reece]

The way that a series light bulb actually works, when used to soft-start a radio, follows. Be sure to understand the electrical terms series vs. parallel.

The idea is that with a radio and a light bulb in series across the power line, both should share the voltage and thus neither one get full voltage, provided neither one is shorted. If the radio were to have a short, the bulb would take the line voltage and save the radio from burning up. It would never flash and go out.

Start with a 60 watt bulb. If the bulb lights to normal or near normal brilliance, unplug everything right away and check for shorts in the radio. If the radio has a short, or partial short, all or most of the line voltage will develop across the light bulb and light it brightly. If this happens, repost your findings and we can give you pointers on how to find the short.

If, as we would hope, the bulb lights very dimly or imperceptibly, you are probably OK as the line voltage is being shared between the radio and the bulb.

If all is OK with a 60, try a 75. If you are monitoring line voltage at the radio (good idea) it won't be at 117 volts yet but possibly around 80 or 90 volts. There may be a crackle or two from the speaker but this depends on whether the rectifier has enough voltage at this point to provide B+. If the set has a power transformer, monitor its temperature.

Finally try a 100 watt bulb. The radio will probably play at this point if it's OK, and the bulb will be dim. At this point you can connect the radio directly to the line. Of course, it is highly recommended that you replace electrolytic and paper capacitors before going any further.

Reece