[apERNA1985]

It's interesting, how far off the Sam's can be. I have to find my philco sheets. I bought the CD off eBay a while ago.

On the bright side my K Networks should be here today.

[apERNA1985]

I finally had a chance to replace the Networks. I have to say Chris's networks are really nice. However I have 2 left over 30-6037-1, and 30-6028-2. The picture is a lot better but still not ok. It fills more of the tube, and I can see most of the vertical lines now. Also I don't understand it, but the white distorted patch moves from the top of the screen to the middle and then the bottom every 10 or 15 seconds, occasionally the screen will be filled with it, then it will go to a different spot. I'm still seeing twitchy lines on a diagonal going through the screen, they have been there since I disconnected the original diodes and replaced them.  Is it possible AC voltage is getting into the chasis and causing my distortion? The picture I have up is the grid pattern. Also should I try tacking on the 2 caps to try and bring voltage up?

[OZ4]

apERNA1885  looking at your pictures. The white diagonal twitchy lines are the horizontal retrace which is normally blanked out but the brightness is up so high that they are showing. This is normal with the brightness all the way up.

Also it looks like the horizontal osc is locking as I can see the grid pattern. Will the picture tear when you adjust the horizontal control?  If it will tear then the oscillator is locking.

Your rolling distortion is likely horizontal Bars banding the screen that can be the line AC interference getting into the video signal coming thru the IF amp. Or maybe getting into the vertical deflection. 

As I understand it BW sets vertical ran at 30hz That's one full screen every 1/30th of a second. Then when the color system came online it chanced to 29.97hz as to not interfere with the color signals. (N.T.S.C.  Never The Same Color twice) And the older BW sets could still lock on to the new 29.97hz vertical sync signal. So when all other things are working this difference is why there can be  moving bars of interference from the AC line. Two bars is 60hz and after the rectifier section 120hz can be four bars.

(Many years ago I was a TV broadcast engineer but didn't work on tv monitors much. I was mostly tasked with keeping the beta tape machines up and running.)

The really fine horizontal lines maybe ringing (high frequency oscillation) in the IF section or the vertical section. 

And there is still distortion in the vertical deflection waveform. Hence the lack of full picture with fold over.

[OZ4]

After thinking about it for a while. The symptom of the grid pattern is being obscured by the rolling banding interference. I think the AC interference is getting into the video signal which is coming from the IF section. It's interesting to note the ringing (very fine horizontal lines) is riding on the AC noise.

You really need a oscilloscope to check the DC voltages for AC noise. And looking for distorted waveforms otherwise you are flying blind.

[mikethedruid]

Just my two cents, but, from what I remember from working on these old analog TVs half a century ago, it looks like your horizontal hold and vertical hold are WAY out of adjustment. The horizontal hold accounts for the many narrow bands, and the vertical hold for the thicker rolling band. Adjust the vertical hold until the thick band stops rolling and you are left with just the narrow bands, then adjust the horizontal hold. As you do, you should see these many lines decrease, and decrease, until you have just one solid raster. Be aware, analog TV is no longer being broadcast. You will have to feed an appropriate signal into the set from an old VHS or DVD player which has an analog NTSB output. That will probably be 75 ohms, so you will need to get an adapter for 75 to 300 ohms, which was the standard input for the twinlead used back in the day. Also, without a signal to latch onto, you will have a very hard time getting a stable raster since the broadcast signal has a synch pulse used by the set to lock the frame scan. If you really want to do it right, I advise buying a vintage TV test pattern generator. They can be found on eBay.
[Image: https://i.ebayimg.com/images/g/BkQAAOSwN...-l1600.jpg]

[apERNA1985]

So I found out the K network for retrace lines was under the chassis and I replaced it, I also replaced the one on the picture tube. Then I tried again to adjust everything and I can't get a good picture. I took a video so you guys can see. One video is a DVD playing, the other is my signal generator showing a 9x9 grid.

OZ4 I'm wondering if I have to rebuild the IF board next.

https://youtu.be/tLdVBiA0Q3A

https://youtu.be/mqBpobUn3Ps

[BrendaAnnD]

I'm seeing some technical misunderstanding going on.

1) NTSC standards are 59.97Hz for the vertical (interlaced traces makes ~30fps) and 15736Hz for the horizontal. This frequency was chosen because it was in sync with the 3.579545 color burst.

The author is using a super cheap basic matrix generator which syncs to both of these. It uses TTL dividers and square waves to reproduce the basic dot/crosshatch patters using different pulse widths. The color it generates by sending a burst pulse.

It's the generator he's using that you're seeing as out of sync/frequency vertical/horizontal. It's actually in sync, but there is some h-k leakage going on, mostly capacitive. My first suspicion could still hold true, and there is a problem with the long cable going between the chassis and CRT.

[Bob Andersen]

Agreed. Could also be an issue with the video amp inside the CRT housing. It is supposed to compensate for losses in the long cable.

[OZ4]

Ok Brenda Yes your are right It's been a long time. Thanks for the correction.

[OZ4]

Brenda what do you think the fine horizontal lines are from.

From the schematic I see the video output tube is with the CRT. Without an oscilloscope don't know how one would troubleshoot. You can't see what the video signal looks like without one.  Did this tube get tested? I see at least three caps in the CRT housing?

One might be able to substitute a piece of RG59 or RG6 TV cable for the video going to the CRT. I sure the impendence is not correct but if it's short enough it should work for testing.

[Mondial]

From the video it almost looks like he has an extreme vertical foldover where the top of the picture is superimposed on the bottom. 

Without a scope its really hard to tell, but instead of a vertical deflection sawtooth wave, he seems to have something like a distorted triangle wave vertical sweep. The deflection signal rises linearly but then instead of falling sharply it decreases as a slower rate which produces a folded over superimposed image.

There also seems to be some hum modulation of the vertical sweep where a 60 hz signal is beating with the 59.94 vertical frequency, causing the image to slowly vertically roll about the foldover point at the difference frequency.

Is there any way that you can get your hands on an oscilloscope, because I don't think you can easily troubleshoot this any further without one.

[apERNA1985]

Ok, from what everyone is saying I really need an Oscilloscope to figure out what is going on. I found a few locally on Facebook, I don't know much about what I'm buying. My only Ocilloscope experience is with automotive sensors and with checking ignition systems, and the scopes we used for designed for that. I found a few scopes with missing leads, are leads specific to the scope or are they easy to find? Also what frequencies am I looking for? I found a nice looking Heathkit one for $50 but it has no leads. I've seen hi end looking ones for $200 and up. How sophisticated of a scope to I need?

[Mondial]

You really don't need the latest and greatest scope, but it should be modern enough that you don't have another restoration project before you can use it properly. I would suggest at least 20 Mhz bandwidth for typical troubleshooting.

Personally, I am partial to the Tektronix scopes built in the 70's and 80's. They are new enough not to need major restoration, yet sometimes can be gotten for less than $100 in good working condition.

The test probes for modern scopes typically have a BNC coax connector to plug into the scope. Some are available with 10X attenuators to look at higher voltage signals without loading down the circuits under test. Inexpensive ones are available for less than $10 on ebay.

I don't know what sort of scopes you are seeing on Facebook, but you might post pictures of a few so we can see what is available to you locally. The seller should be able to show you that it is operational and can produce a sharp clean trace or waveform before you consider buying.

[apERNA1985]

The first one is a Hitachi 1065a it says it works but has no probes he wants $100

Heath kit IO-14 says powers up but no probes $80

There's this one made by Rigol too that one is $75



Other than that there's a bunch of untested ones and ones over $200.

[Bob Andersen]

If I had to choose between those, I'd definitely go with the Hitachi. 100MHz dual channel analog scope.

It uses standard 10X scope probes. You should be able to use some cheap generic ones like this:
https://www.ebay.com/itm/324999641806?ha...Sw~JZh5DGC


Max DC voltage on the scope input is 500V so be careful. Don't go probing around the vertical output transformer or horizontal output tube.

You can get a free manual here.
https://www.allaboutcircuits.com/test-me...5a/manual/

I see it has dedicated TV-V and TV-H triggering modes. That may make examining video signals a bit easier..