ideal response 80

[AGAS]

Possibly only the 120 though.

iirc on the 100 as well ???

 

[bernardgreen]

Any electricians online who can explain this statement.

You can make a resstor by drawing a line on paper with a graphite pencil and then use two paper clips to make the contacts. This was very common in the early days of radio.
Cut and pasted to save typing

The pencil mark grid leak resistor was primarily a home constructor device that worked the same way as the commercial versions but was cheaper. It
was just a line drawn on a piece of cardboard usually with screws, nuts and washers as contacts. Experimenters liked them because you could rub on, or erase off, pencil lead until you got optimum resistance. They were somewhat permanent. As far as the type of line used, you just drew back and forth between the contacts until you got the resistance you wanted. I have a radio with one and it works just fine. Grid leak resistors allowed electrons to leak off the grid to keep the operation of the tube from blocking up.