First post in here about a TV! I'm the proud new owner (3rd owner!) Of a 1957 Motorola black and white TV!

I am very proficient in tube amplifier work and have designed my own, as well as run a restoration shop for vintage tube and ss audio. I'm very good at aligning FM and AM tuners etc. However, when it comes to TV, I understand some of the tech transfers over...and I understand how an o-scope CRT works...but thus tv has been kicking my ass.

I've gone through and recapped the set completely...electrolytics and all paper caps. It came to me semi-working (was supposedly working before but you know how that goes....)

I'm using an RF converter box to run a DVD player into it. I've also added an external coax input to the input of the video amplifier to attempt to directly inject a signal there, but I'm having issues with the screen alignment.

I took a video of it as you turn it on. https://youtu.be/OUSmtnTyIDw

You can see off to the right of the video what the picture should be (playing on my wide screen modern flat screen tv.) When turning on, as the set warms up it plays the picture worse and worse and the audio fades to being fairly quiet with the volume maxed out.....with a pair of 6aq5s into a 6x9 I would think this set should be a relative thumper.

To me, it appears that the vertical scan is squashed or unstable. If I'm tuned off station, I have horizontal lines (well, they look more like curve plots on a tube data sheet.)

I'm hoping someone here can give me guidance on where to move next with the set. My end goal is to be able to load a firestick full of old movies and run through an HDMI to Composite converter and plug straight into the video amp, bypassing the RF section of the tv...which should be fairly simple.

I see 3 tubular ceramic (paper dielectric) caps in the top right of the 3rd picture...Those should be changed if they haven't been.

A picture of the screen running would be more helpful than a description.

It sounds like you may have both sweep and tuner/IF issues.

Hi, thanks for the reply! Yes that was a mid recap picture those have been changed now. I edited the post with a link to my YouTube video of it running :)

Also, I dony know that it is in the IF section, as injecting the coax video signal directly into the "test" (video amp input) port provides the same exact results.

Your video comes up as unavailable - private.

The lines when tuned off station sound like lack of vertical retrace blanking. If it only happens off-station, not sure if it's a defect or just a design issue, but in most TVs it should not happen either on or off channel.

Fix the YouTube video and people can offer more help.

Hi, I fixed the link...hadn't made it public by accident.

Off station is snow like normal, but when in increase the vertical and horizontal hold it gives me the lines at the bottom of the screen.

That's a vertical compression/foldover at the bottom. Vertical deflection circuit needs some out of tolerance components replaced or maybe just a new tube or two to get a linear waveform of full amplitude. Should be fairly easy to find.

In the video, the picture contrast looks very weak, which could be why the sync is bad. Could be a tuner or IF issue, or AGC. Have you checked/replaced any tubes?

The snow test is great. Wish everyone knew it.
Anyhows your snow is there BUT its streaky.
For now try the AGC & or fringe lock controls.
After that check the IF, AGC & tuner tubes. A tester
may or may not show a bad one. Just cant trust testers.
Next step is voltages. After that ingecting with an anylist
is fastest.

73 Zeno:smoke:
LFOD !

To me it looks like the picture is severely stretched horizontally.
You do realize that the widescreen (HDTV) aspect ratio of 16:9 won't fit the 4:5 ratio of vintage NTSC screens. I can't see enough of the flat screen to figure out which ratio the video signal is in.
It could be that the width is adjusted far to wide, but I've never seen a vintage TV that would adjust to that extreme so I think it is something else.
It is best to used a still image at this point to trouble shoot, pause the video if you don't have test pattern generator. Something like the CBS eye is a good image but it would have to be on a DVD for your current set up.
I wouldn't worry too much about what the TV is doing tuned off station, without a good video signal the horizontal and vertical sweep circuits won't have a good guide to operate.
Go after one thing at a time, get the picture sweep working right, then work on the video signal (and IF, RF).

I would think you have an oscilloscope if you are as experienced as you say.
Do you have a SAMS for the TV? It usually has some waveforms that you can compare to what you see on the oscope.

Yes, I do have a 2ch hameg oscope. I've got the Sam's for the TV, I need to upload the model number when I get a free minute this weekend. I appreciate ALL of the replies and will pour over them more in depth when I get a chance.

Of note, I tested all tubes on my Triplett 3444 and replaced a couple that were worn beyond what I felt confident keeping in the set, but that did not change anything.

Yes the contrast does appear to be out of whack.

The DVD player im using for testing has a force 4:3 output setting for Composite out, and the tv reacts the same way regardless of if it is run through the converter box into the antenna input or through the tapped video amp input.