I’m trying to repair a 63 year old record player. Opening it up, all of the electronics have aged badly, except for the drive motor, which is basic enough that it operates properly. I know enough about the resistors and capacitors that I can just get modern equivalents that will last much longer than their 50s counterparts, but what I’m concerned about are the vacuum tubes, one 35W4 and a 50C5.
This image is of the tube’s socket pins. The top tube is the 35W4, while the bottom tube is the 50C5. You can see a bright bluish-white line of electricity connecting two pins together. It doesn’t seem to go away until I cut the power. The 50C5 seems to be experiencing spark gaps, if that’s the proper term, between pins 6 and 7, along with making an annoying buzzing noise. I don’t leave it powered on because I don’t know if it will start a fire, explode, etc. Tubes aren’t my specialty, but I know they’re dangerous. Does this mean anything is happening to the tube? Is it faulty?
Here is a picture of the record player schematic.
The white powdery substance is just a 250 ohm Lectrohm resistor, I’m not sure why it uses powder, it is some 60 years old, but it isn’t functional and the resistance has dropped drastically.