07-21-2018, 05:06 PM
O
Got a 39-6 that was DOA. After recapping and switching out resistors that read bad, it now comes on and the tubes light. However, my 6A7 (Det-Osc) has me puzzled.
Off of a dim bulb tester with a 65W bulb (39-6 requires 40w), the 6A7 is bright and the blue light will pulse along the grid section (see pix). With a loop antenna, I can get a station when I touch the grid cap of tube 78 (IF). My 6A7 reads are: pin 2(plate) is 191v the schematic shows 145v. Pin 3 (screens 3&5) read 122 and the schematic shows 75v. Pin 4 (grid#2) is 192v and the schematic shows 145v. On pin 1 which is my heater feed, I get 5.6vac and the spec sheet for the tube shows 6.3 v.
I have a 6A7 on another working Philco but I'm afraid to switch it for fear my issue may not be the tube but something else.
I have no tube tester, just a multimeter. Any suggestions?
Mark
Off of a dim bulb tester with a 65W bulb (39-6 requires 40w), the 6A7 is bright and the blue light will pulse along the grid section (see pix). With a loop antenna, I can get a station when I touch the grid cap of tube 78 (IF). My 6A7 reads are: pin 2(plate) is 191v the schematic shows 145v. Pin 3 (screens 3&5) read 122 and the schematic shows 75v. Pin 4 (grid#2) is 192v and the schematic shows 145v. On pin 1 which is my heater feed, I get 5.6vac and the spec sheet for the tube shows 6.3 v.
I have a 6A7 on another working Philco but I'm afraid to switch it for fear my issue may not be the tube but something else.
I have no tube tester, just a multimeter. Any suggestions?
Mark
