Greetings, I'm working on getting the radio section of this turntable combo working. It is my first try at repairing a tube radio. The radio didn't work when I got my hands on it. Using a Sams schematic, I've replaced all the paper caps. I've been working through the resistance measurements listed for each tube and most are within +/- 10%. I've found a couple of resistors that are quite a ways out of tolerance (and I'll replace those) but I've run into something I can't figure out on the rectifier tube (35W4). The resistance measures close to spec on all pins but 1 and 7. When I measure these two pins the resistance starts around 11Meg and then slowly drops (like charging a big cap). The schematic shows pin 7 going to the filter caps through a 47 Ohm resistor. But what I SEE is pin 1 going to pin 7 through the 47 Ohm resistor, and then tied with a wire to the filter caps. Does this make sense?
By the way, the resistance on pins 1 and 7 should be 60K and 45K respectively.

Scott, how are you measuring these resistances - from pin-to-pin with the tube pulled or with the tube installed in its socket?

Pin 1 of a 35W4 isn't connected to anything inside the tube - it's labeled "NC" on the 35W4 data sheet. Now it's very possible that the manufacturer used this pin for a convenient tie point for other components, but this normally wouldn't be shown on the schematic.

:Greetings, I'm working on getting the radio section of this turntable combo working. It is my first try at repairing a tube radio. The radio didn't work when I got my hands on it. Using a Sams schematic, I've replaced all the paper caps. I've been working through the resistance measurements listed for each tube and most are within +/- 10%. I've found a couple of resistors that are quite a ways out of tolerance (and I'll replace those) but I've run into something I can't figure out on the rectifier tube (35W4). The resistance measures close to spec on all pins but 1 and 7. When I measure these two pins the resistance starts around 11Meg and then slowly drops (like charging a big cap). The schematic shows pin 7 going to the filter caps through a 47 Ohm resistor. But what I SEE is pin 1 going to pin 7 through the 47 Ohm resistor, and then tied with a wire to the filter caps. Does this make sense?
:By the way, the resistance on pins 1 and 7 should be 60K and 45K respectively.

:Scott, how are you measuring these resistances - from pin-to-pin with the tube pulled or with the tube installed in its socket?
:
:Pin 1 of a 35W4 isn't connected to anything inside the tube - it's labeled "NC" on the 35W4 data sheet. Now it's very possible that the manufacturer used this pin for a convenient tie point for other components, but this normally wouldn't be shown on the schematic.
:
::Greetings, I'm working on getting the radio section of this turntable combo working. It is my first try at repairing a tube radio. The radio didn't work when I got my hands on it. Using a Sams schematic, I've replaced all the paper caps. I've been working through the resistance measurements listed for each tube and most are within +/- 10%. I've found a couple of resistors that are quite a ways out of tolerance (and I'll replace those) but I've run into something I can't figure out on the rectifier tube (35W4). The resistance measures close to spec on all pins but 1 and 7. When I measure these two pins the resistance starts around 11Meg and then slowly drops (like charging a big cap). The schematic shows pin 7 going to the filter caps through a 47 Ohm resistor. But what I SEE is pin 1 going to pin 7 through the 47 Ohm resistor, and then tied with a wire to the filter caps. Does this make sense?
::By the way, the resistance on pins 1 and 7 should be 60K and 45K respectively.

Hi Doug, thanks for the reply. I'm measuring resistances with the tubes installed in their sockets using values from the radio circuit schematic. I will double check how the socket is wired when I get the chance. You are right that pin 1 isn't shown on the schematic, but then that means (in this radio) that pin 7 is wired straight to the filter caps and not through the 47 ohm resistor. confusing!! For what its worth, the tube tests good on my Sencore portable tester.

:Scott, how are you measuring these resistances - from pin-to-pin with the tube pulled or with the tube installed in its socket?
:
:Pin 1 of a 35W4 isn't connected to anything inside the tube - it's labeled "NC" on the 35W4 data sheet. Now it's very possible that the manufacturer used this pin for a convenient tie point for other components, but this normally wouldn't be shown on the schematic.
:
::Greetings, I'm working on getting the radio section of this turntable combo working. It is my first try at repairing a tube radio. The radio didn't work when I got my hands on it. Using a Sams schematic, I've replaced all the paper caps. I've been working through the resistance measurements listed for each tube and most are within +/- 10%. I've found a couple of resistors that are quite a ways out of tolerance (and I'll replace those) but I've run into something I can't figure out on the rectifier tube (35W4). The resistance measures close to spec on all pins but 1 and 7. When I measure these two pins the resistance starts around 11Meg and then slowly drops (like charging a big cap). The schematic shows pin 7 going to the filter caps through a 47 Ohm resistor. But what I SEE is pin 1 going to pin 7 through the 47 Ohm resistor, and then tied with a wire to the filter caps. Does this make sense?
::By the way, the resistance on pins 1 and 7 should be 60K and 45K respectively.