04-23-2015, 07:17 PM
You can check most of the windings with a couple simple tests at the seller's house.
1. Unplug the radio, turn the power switch on, measure resistance through the primary across the pins of the power plug. Usually 10s of ohms.
2. Pull the rectifier, measure the 5V winding resistance across the heater pins of the rectifier socket. Should be a near-short (tenths of an ohm).
3. Measure the high-voltage winding resistance across the plate pins of the rectifier socket. Should be several hundred ohms.
4. Then, as stated previously, leave the rectifier out, plug the radio in, and see if the heaters of the other tubes light up.
The most common way this fails is that the power switch is failed open, which means you can't do checks 1 and 4.
1. Unplug the radio, turn the power switch on, measure resistance through the primary across the pins of the power plug. Usually 10s of ohms.
2. Pull the rectifier, measure the 5V winding resistance across the heater pins of the rectifier socket. Should be a near-short (tenths of an ohm).
3. Measure the high-voltage winding resistance across the plate pins of the rectifier socket. Should be several hundred ohms.
4. Then, as stated previously, leave the rectifier out, plug the radio in, and see if the heaters of the other tubes light up.
The most common way this fails is that the power switch is failed open, which means you can't do checks 1 and 4.
