1950 Admiral 21D1 No sound, and 2 vertical lines in center of screen?

[Magnavox300]

Trying to figure out why my 1950 Admiral has 2 white lines in the middle of the screen, which breaks up the picture; also has scratchy to basically no sound... always a crackling popping sound in the speaker.... any tips?? Tested all tubes, new capacitors were put in a few years back and resistors were tested... maybe something went? Any tips where to check first??

[old_tv_nut]

Horizontal drive problem. If there is a horizontal drive or efficiency adjustment, try that. Try replacing tubes in the horizontal section. If no luck, have to start looking for bad parts.

Do the sound crackles get worse while moving the volume control?

[old_coot88]

For the sound problem, I would first try the 'tap test' and 'wiggle-in-its-socket' test of sound tubes. Very often, this'll show up any intermittent tubes or oxidized contacts. In fact, 'tap & wiggle' of signal tubes and damper was basic SOP on all service calls back in the day (at least with our shop). Arcing dampers was always the biggest thing to show up from tapping.

[Magnavox300]

Thanks for the good advise... adjusting the horizontal drive did it, along with replacing the horizontal 6DC6... Picture is back to normal!
Still bad audio though, very faint, just loud sporadic crackling, (either with volume up or down, louder when turned up)..... Strange thing is the audio finally came in and crackling noise went almost completely away after the set warmed up for about 1/2 hour to an hour...
Wondering what component might be the culprit, which after it heats up, gets better?? I have checked everything, except some of the ceramic capacitors...

[timmy]

How about the volume knob maybe dirty spray it up.

[Magnavox300]

Originally Posted by timmy

How about the volume knob maybe dirty spray it up.

Thanks, sprayed it out with deox twice, not it... It's intermittent, like a tube shorting or something... tested them all though...

[Electronic M]

If you can run the chassis out of the cabinet and get it to act up, then you can probably find the issue by hitting components in the effected circuits with freeze spray. If it's a tube pull shields and observe in a dim room, you'll probably see some interesting colors in the bad tube.

[Magnavox300]

Originally Posted by Electronic M

If you can run the chassis out of the cabinet and get it to act up, then you can probably find the issue by hitting components in the effected circuits with freeze spray. If it's a tube pull shields and observe in a dim room, you'll probably see some interesting colors in the bad tube.

Thanks... I pulled the chassis out, removed the shields, and didn't observe any unusual colors.... Picture is perfect, except the crackling in the audio distorts the picture and makes it roll, or throws the horizontal off... picture goes back to normal when the audio crackling calms down...

[Magnavox300]

Originally Posted by Electronic M

If you can run the chassis out of the cabinet and get it to act up, then you can probably find the issue by hitting components in the effected circuits with freeze spray. If it's a tube pull shields and observe in a dim room, you'll probably see some interesting colors in the bad tube.

Will try the Freeze Spray, didn't know about that!

[bandersen]

Could be silver mica disease in the IF cans. Admiral used exposed caps in the IF cans like the two 30pF shown in this 1949 Admiral sound IF can.