Just a few questions for you guys who remember the old B/W round screen televsions.
I'm working on a 50 -1430 T, code 125 Philco television from 1950. I have replaced the electrolytics and am in the process of replacing the wax/paper condensers. The set warms, shows a lit screen on the top 3/4, then a bright band, and is dark on the bottom 1/4. I have ordered a new 7N7 vertical output because it showed high grid emission on the tester and was glowing purple in the set. I hope this satisfies the problem. Is it a safe assumtion that the yoke and flyback are OK in this set because of the appearance of the picture or could either be causing the problem?
The new challenge is figuring out why I can hear the hum of the amplifier circut at full volumn, but have only a very faint static sound. All of the other tubes are tested/checked - still do not seem to receive any picture/sound, Should the tuner be the next area of focus, (It is a floating chassis type but is strangely grounded to the set chassis when checked with an ohmmeter) or do any of you fellas who remember this stuff have another suggestion...

Justin

A tube that glows purple is gassy and should be replaced. Sometimes tubes will show a blue color just inside the glass. These are ok.

Check components around the vertical output tube. Philco must have different versions of this TV as the schematic I have shows a 6AQ5 vertical output. The yoke and flyback transformer are most likely ok.

The tuner in this TV has a lot of contacts. Cleaning them with TV Tuner Cleaner may prevent a lot of troubleshooting.

Norm

: Hello group,

: Just a few questions for you guys who remember the old B/W round screen televsions.
: I'm working on a 50 -1430 T, code 125 Philco television from 1950. I have replaced the electrolytics and am in the process of replacing the wax/paper condensers. The set warms, shows a lit screen on the top 3/4, then a bright band, and is dark on the bottom 1/4. I have ordered a new 7N7 vertical output because it showed high grid emission on the tester and was glowing purple in the set. I hope this satisfies the problem. Is it a safe assumtion that the yoke and flyback are OK in this set because of the appearance of the picture or could either be causing the problem?
: The new challenge is figuring out why I can hear the hum of the amplifier circut at full volumn, but have only a very faint static sound. All of the other tubes are tested/checked - still do not seem to receive any picture/sound, Should the tuner be the next area of focus, (It is a floating chassis type but is strangely grounded to the set chassis when checked with an ohmmeter) or do any of you fellas who remember this stuff have another suggestion...

: Justin

I am new at TV repair. I have found that the paper caps and electrolytics caps need to be replaced first. This seems to clear up 80% of all problems. The set I am working on now went from dead to working with vert problems by only changing caps. Norms right on the tuner cleaner it remove much of the problems in that section. The hum you have may be the filter caps in the audio section.

Tom Guest