I am hoping some knowledgable person out there can tell me how to test continuity on tubes. I understand you are to use the 2 filament prongs, however how do you know which of the prongs are for the filament? I have many to test but right now I would like to test the following: Arcturus tubes: (2) are marked "551" on the base one of them is missing the silver cap atop the tube itself; (1) marked "124"; (1) marked "127"; (1) marked "PZ"; (1) marked "180" and last a Philco is marked "7S".

Thanks to any and all for assistance,
Phil Branch

Use the "tubes" link at the top of this page and then select a tube number (80) for example.

It will give you two to choose from, so just select the 80.

A picture will appear of the pin layout and the filament pins are marked "F". On this tube, they are the two largest diameter pins.

Other configurations show a "key" or extruded part at the base of the tube that is used to reference the pins and what they are for. Count clockwise from the key to get to the right pin(s).

Hope this help.

Terry F

:Use the "tubes" link at the top of this page and then select a tube number (80) for example.
:
:It will give you two to choose from, so just select the 80.
:
:A picture will appear of the pin layout and the filament pins are marked "F". On this tube, they are the two largest diameter pins.
:
:Other configurations show a "key" or extruded part at the base of the tube that is used to reference the pins and what they are for. Count clockwise from the key to get to the right pin(s).
:
:Hope this help.
:
:Terry F

Thank You Terry, That was a simpler than I thought it would be.

Regards,
Phil

ebay has RCA and other tube manuals for sale. They show the various pin locations. Should be costing $10 or less.