01-24-2010, 11:09 PM
This restoration has been a challenge. The radio was dead. All of the old paper caps and the electrolytic was replaced. Most of the resistors were good but the filter resistor was short lived. It turns out that the AF and IF trim capacitors were shorted to the chassis. The original was 2200 ohms and I replaced it with a 1700 ohm 10 watt resistor so I could have enough time to measure the voltages. The B+ and chassis were identical and the I had a a 125 volt drop across the filter. I tracked down the short by checking continuity at a B+ node and followed the branches. I'm somewhat surprised that the trimmers were the problem because there was no short at first.
The trimmers seem simple. A screw controls the distance between two plates which in turn determines the capacitance. I can open and close the distance between the two plates and the capacitance doesn't change as measured by my multimeter. I'm not sure if they are good or bad since I'm not sure if a multimeter can make that measurement. I need to do an alignment so a quick check would come in handy and save a bunch of time. Getting the tuning set will be odd. This set has permeability tuners - little coils with an iron core that's pulled in or out of the AF and IF coils. Fortunately, I have a good reference book and the alignment instructions from the manufacturer.
Antenna: The schematic shows no loop and none came with the radio. Reception is weak unless I touch the antenna and that's not good thing to do with this radio. I would think there has to be a loop that was removed. Otherwise, people would be getting electrocuted. If anyone has one similar to the GE50/Musialarm and know about the antenna, you help would be greatly appreciated.
The trimmers seem simple. A screw controls the distance between two plates which in turn determines the capacitance. I can open and close the distance between the two plates and the capacitance doesn't change as measured by my multimeter. I'm not sure if they are good or bad since I'm not sure if a multimeter can make that measurement. I need to do an alignment so a quick check would come in handy and save a bunch of time. Getting the tuning set will be odd. This set has permeability tuners - little coils with an iron core that's pulled in or out of the AF and IF coils. Fortunately, I have a good reference book and the alignment instructions from the manufacturer.
Antenna: The schematic shows no loop and none came with the radio. Reception is weak unless I touch the antenna and that's not good thing to do with this radio. I would think there has to be a loop that was removed. Otherwise, people would be getting electrocuted. If anyone has one similar to the GE50/Musialarm and know about the antenna, you help would be greatly appreciated.
