Currently working on a Goblin Time Spot with a field coil speaker. The speaker cone was badly torn and the field coil was open circuit so my initial thought was to replace it with a permanent magnet speaker and a separate filter choke. However, curiosity got the better of me so I decided to start unwinding the coil to see if I could find the break. Of course once you have started.....! About 3 hours later found the break right at the start of the coil! Break repaired and coil re-wound (another 3 hours), patched up the torn cone and the speaker is now working perfectly. I'm a happy bunny
The coil is 1500 ohms of 35 awg which equates to just under a mile of wire all done by hand - I think I've earned a beer