03-13-2015, 10:15 PM
(03-13-2015, 07:41 AM)Mondial Wrote: Keith, the cathode of the 6A7 (pin 6) is grounded on the second type schematic. There may be one, two or even no resistors actually connected to the socket pin since any convenient chassis ground will serve the same purpose. Is your pin 6 directly connected to chassis or is there a 300 ohm resistor to chassis ground?Pin 6 is not connected to the chassis and it has a single resistor that connects it to ground. The resistor measures 20 ohms. It appears to be brown (body), black(end), black (spot). But the color isn't clear and it's possible that it's a orange, brown, brown that got hot and changed colors. However wouldn't the resistor go up in value over age and not down in value? Here's a picture cathode resistor . From the picture you can see that it's not clear if the body is brown, red or orange, it looks like a mixture of the three colors.
When they drew the schematic, it was easy to draw the resistors as shown, but it does not necessarily imply that they were actually located and connected there.
Keith