Vintage 1940s RCA Power Supply Unit for Signal Mixers MI-4304

Description

For restoration. Rare vintage 1940s RCA Power Supply Unit for Signal Mixers MI 4304. RCA Sound Equipment Catalog 218 (which you can download) says this power unit can be used with Tube Voltage Amplifiers MI-4273 and MI-4297 and supplies power for up to six signal mixers, compander or booster amplifier.  It will need a new Type 80 Rectifier, all the caps replaced, and 2 25-watt wire-wound resistors. I have checked the power transformer and the filter choke and on both I detected no shorts or open windings. The primary DC resistance measured at 19.2 ohms.  The high voltage winding DC resistance measured at 1.4 K.  From center tap to rectifier plate number one measured 739 ohms.  From center tap to plate number two measured 697 ohms. 5 volt winding DC resistance measured .6 ohms.  6 volt winding DC resistance measured 2.9 ohms. Filter choke DC resistance measured at 349 ohms. The power supply was fused at 2 amps.