[IowaPhilco]

Hello all, new to the forum. I have a Philco 80 Jr. that I'm repairing / restoring. The first question I have is just how "hot" is normal for the rectifier tube? I put a temperature probe up against the glass and base and it read around 140 degrees Fahrenheit. I know it is normal to get warm, just want to make sure its not too hot.

A little back story on this radio. This radio has been in the family since it was new. This was the first tube radio I ever repaired. Back then the 4mF cap failed and a resistor was burnt. That was 22 years ago and I kind of got out of the hobby (kids and wife, etc.) Now kids are grown and I have time to re-learn. This radio stopped working again when the rectifier tube failed. I replaced the tube and it works but gets very warm. I'm slowly replacing all the caps and out of tolerance resistors. So far both the electrolytic caps and one of the Bakelite block cap (the one with the wire wound resistor) have been rebuilt. One part at a time to make sure it is still working. Any information and advise would be appreciated. Thanks.

Hi Mike,

If the tube is overheating good chance it’s shorted. The amount of current your radio is using will indicate if it’s shorted. To determine how much current the radio should be using calculate it by solving P=E*I where P is Watts, E is volts and I is amperes. You can get watts from the back of the radio or the wiring diagrams, the volts is from your power source which should be matched to Philco’s recommended operating power.
With that operating current value in hand put an ammeter in series with the power supply and measure. If the current is normal then don't worry about the tube, it's likely operating normally. If the current is too high then this explains why your tube may be getting hot.