vintage radio

Hi there, I recently got an old GoldStar GSM-6330 and wanted to add an internal Bluetooth-receiver to it, without sacrificing any of the existing functionality. I decided for some cheap Bluetooth receiver board. You can see on this image, how I wired everything. (I stole the +-12V from the...

Please help. Considering building a vacuum tube tester from an old magazine design. Parts seem to be an issue because of the 1950’s era age of the design. I want to replace a Sarkes Tarsian Selinium voltage doubler Rectifier part # 78D. Is there a modern day equivalent to this part?