Only $5 for 10 PCBs and every new member get $5 bonus. + Express 24 hour / 48 hour service on https://www.pcbway.com/ ➠ ➠ ➠ In this video, I’ll show you how to replace the selenium rectifier in vintage tube radios with modern silicon diodes, while maintaining the proper voltage drop. Since silicon diodes have a lower voltage drop than selenium rectifiers, I’ll be using a MOSFET and a trimmer potentiometer to provide an adjustable voltage drop. This allows you to fine-tune the voltage to match the original circuit specs, ensuring your vintage radio operates smoothly without over-stressing any components.
This solution is practical and easy to follow, whether you’re restoring a classic tube radio or simply looking for a modern and safe replacement for the selenium rectifier.
NOTES:
The Tab of the Mosfet is at the '-' potential, so the bolt connecting it to the PCB and then to the Chassis must be a nylon one if the chassis is not a common GND.
Before applying power to the board, set the Trimmer Pot to about half-way to prevent the Mosfet from being OFF when power is applied. This will prevent the circuit from seing the full B+ across it, which may damage the Trimmer Pot.
➠ TO ORDER PCB'S:
https://www.pcbway.com/project/shareproject/Bridge_Rectifier_with_Mosfet_Voltage_Dropper_2024_09_02_09347b93.html
➠ Links Mentioned in this Video
RG Keen's Mosfet Follies: http://www.geofex.com/Article_Folders/mosfet_folly/mosfetfolly.htm
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#TubeRadioRestoration #SeleniumRectifierReplacement #SiliconDiodeFix
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