It followed me home... Philco roundie

[yagosaga]

Originally Posted by RetroHacker

Well, I got the schematics and did some voltage checks. These are all measured from chassis ground:

Screens:
Pin 3 (Red) - 435v
Pin 7 (Green) - 433v
Pin 11 (Blue) - 435v

Grids:
Pin 2 (Red) - 72v
Pin 6 (Green) - 87v
Pin 12 (Blue) - 80v

Plates:
Pin 4 (Red) - 182v
Pin 5 (Green) - 191v
Pin 13 (Blue) - 181v

So... I'm getting voltage into the tube. All three filaments light. Why no green?

I believe that you measured positive voltages, yes?

These voltages are OK. It seems that the green gun is weak. Try the following: turn the screen voltages for red and blue as low as possible with the screen controls. So you probably will get something around +300v. Increase the green screen voltage up to 700 or 800 volts. The screen should be green now. Does it?

If it is so, I will explain you the next step.

- Eckhard

[RetroHacker]

No, I can't get green no matter what I do. I tried adjusting the screen contols. And I can't really even get a full clean bright color of red or blue either. But, I do have one new bit of test gear, accquired just today. The B&K Precision 470 Picture Tube Tester.

I finally own a picture tube tester! A couple of the adapters are missing, but, the round color tube socket is here, and that's the one I need.

So, I read the manual for the tester, and hooked it up. I found that I was totally unable to set the G2 cutoff for green at all. Red and blue went OK. Then, I checked emissions. Red is in the BAD, green doesn't even register, and blue is in the ?? between GOOD and BAD, but just barely. Well, that explains it. This tube is completely shot.

So, this project is on hold, until I can find a picture tube.

-Ian