10-12-2007, 11:02 AM
Had some time to play with the 531 today and found a bad solder joint on the ground lug of the transformer coupling the first and second AF stage. Now I get a slight buzzing in the speaker. Did a voltage check with just the rectifier tube installed and had 302VDC at point "G" on the schematic. For kicks I hooked up an iPod shuffle into the phonograph jack and the AF section is working. Still nothing from the tuner though. Eliminated the first through third RF tubes by subbing them into the first AF socket and all appear to work. Possible detector tube failure or something else to check (plate voltages, etc.) Thanks.
