I am working on a Zenith 6D311. The set came with a ballast tube, but the dial lamp did not work. After spending some time trying to find the source of why the pilot lamp did not work, I eventually came to the conclusion that I had one last idea. The two wires to the lamp were connected to the ballast tube.
I had a spare ballast tube from another set and made the switch. The pilot lamp glowed nicely.
How do I buy another ballast tube? The schematics for the Zenith 6D311 only states that it is a ballast tube.
Can any type be used?

Hi

Ballast tube is a Zenith 100-70. It drops 49 volts @ 300 ma. There is a jumper between pin #3 and #4. Main resistance element between pin #3 and #7. Lamp tap between pin #7 and #8.

This is a popular voltage drop. Ballasts like K49B would work but need to jump pins #3 and #4 at the socket.

Check AES, www.tubesandmore.com or PTOP http://www.oldradioparts.com/2a2fl.txt

I understand.
Thank you.

AES has the T-URB-009-BT, they show the resistors in it. You would need to jumper pins 1&2.

Don

Has anybody actually bought an used a URB-009? The web page is missing info, I asked AES, and they never answered.

Thanks,
Dave Wise

Dave, What info do you need? It shows which pins the resistors are connected to, I hope the diagram is correct, and it goes in an octal socket. Ohms Law shows that you need all of the resistance, so jumper pin 1 &2 in the socket.
Don

Sorry Don, I meant URB-010. It's the blank one, not URB-009. I mistook URB-009 for it. So my question is off-topic, but still: Does anyone have specs on URB-010?

Dave Wise

Dave, The URB-010 is a mystery. Open a new topic for it, see what answers you get. It can still be ordered.
Don

True enough, and it's just a few bucks. Next order, I'll get one.

Dave Wise