Emerson 609 projection TV

[WISCOJIM]

What about trying to view the CRT image in the reflection of a regular mirror. Can you get one in position to do that?

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[old_tv_nut]

Originally Posted by WISCOJIM

What about trying to view the CRT image in the reflection of a regular mirror. Can you get one in position to do that?

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X rays do not beam straight out the front. They spread in all directions.

[WISCOJIM]

Originally Posted by old_tv_nut

X rays do not beam straight out the front. They spread in all directions.

I was thinking of giving him an angle to see inside, such as using a hand mirror.

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[EdKozk2]

Hi Phil,
Your picture of the egg shaped vertical test pattern reminded me of the issue I had with my Stewart Warner 9100 mirror lid set. In order to correct it in my case I made a change to the RC time constant in the plate circuit of the vertical blocking oscillator. The original per Sams' was a 0.15mfd cap and a 2200 ohm resistor. I ended up using a 0.1mfd and 330 ohm resistor to get a balanced ellipse vertically. Increasing the width adjustment then made the the image circular.
You made great progress.
Ed

[Username1]

Kindof a slow evening, and this thread caught my attention....

" Not a great improvement, but something. It still feels like the horizontal circuits are
just "off" in general -- the adjusters for horiz drive, horiz linearity, and horiz size are
all maxed in one direction. "

I wonder, Could you post a picture however bad it may look with all those knobs
set at mid-point...?

Another goofy thought..... Is there any chance that the metal housing with all
that optics has been magnetized...?

I guess a quick answer might come if you looked at the picture outside all
that optics..... But then I did read about your worry of x-rays....

With both H and V off in linearity, are the V lin and V height also maxed in one
direction ?

Seems like a voltage rail common to both H and V would be a good place to look.

Looks like that will be a neat tv !


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[Phil Nelson]

I decided not to mess with the optics until I have more faith in the electronics. Looking back at my notes, I saw several components still unchecked in the vertical & sync circuits. Plus, I want to check voltages in the sync & sweep circuits. The Sams manual doesn't show any oscilloscope waveforms, but the Riders manual includes a few, so scoping is also on the list.

Time to finish my homework, in other words, before I look for more exotic causes.

The first resistor I checked today was a 3W dogbone style. It's spec'd at 10K and it measured at 24K (!). At first glance, you might think it's wirewound, but this just looks like a fat carbon rod with leads attached to the ends. Way out of spec, anyhow.

I believe the vertical linearity control was also maxed. Not vertical size, though.

Hope to spend more time on this over the weekend.

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

[Josef]

I'd reverse the vertical and horizontal deflection wires and see what happens. If the pattern is mirrowed the defect comes from the electronics, if it stays the same the optics are faulty

[Phil Nelson]

Originally Posted by Josef

I'd reverse the vertical and horizontal deflection wires and see what happens. If the pattern is mirrowed the defect comes from the electronics, if it stays the same the optics are faulty

Josef's test shows that the defect is in the electronics.

I reversed only the horizontal wires (pins 5 and 7 in the previous schematic). That should answer the basic question. Here, they are connected normally:



Horizontal wires connected normally:



Horizontal wires reversed:



The distortion flips horizontally, so clearly the big defect lies in the electronics. Thanks for suggesting this simple test, Josef!

That's actually a relief. Although I don't have an immediate solution for the electronics, that sort of problem-solving should be easier than trying to fiddle optical parts inside the Protelgram "black box" without the factory jigs originally used to align them.

Now I will put the three chassis back onto the workbench and resume my homework (testing voltages, etc.).

Regards,

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

[Phil Nelson]

I finished my voltage-testing homework, checking all the voltages against the chart in the Sams manual (https://antiqueradio.org/art/Sams%2090-6.pdf). This spreadsheet shows the test results (ideal = voltage from the manual, actual = measured voltage):

https://antiqueradio.org/art/Emerson...nVoltages.xlsx

The tests were done with the line voltage held at 117VAC on a variac. I turned down the brightness and audio volume controls; the horizontal & vertical hold controls were set for a normal picture.

Not surprisingly, given that most of the TV works fine, most of the voltages are in about the right ballpark. The filament voltages look somewhat low everywhere, measuring about 5.7 - 5.8VAC rather than 6.3 volts. None of the other results looks like a big red flag, although possibly I'm misinterpreting something.

I'm back to seeking a cause for the bad horizontal linearity. As mentioned earlier, adding a cap across the width coil increased the width and somewhat affected the linearity, but it wasn't a miracle cure. I suppose I could go back and fiddle with different values for that cap.

There isn't much else to tweak in that circuit, although I see two caps on either side of the horizontal linearity adjuster (C-65 and C-64 in the Riders schematic below). Those wouldn't be difficult to change, if there's a reason to try that.

Any other ideas?

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

[Tom9589]

I don't think that will work as the horizontal and vertical yoke windings are quite different in resistance and inductance.

[Phil Nelson]

I thought Josef meant swapping the horizontal wires (pins 5 & 7 in the schematic) with each other and then swapping the vertical wires (pins 2 & 6) with each other. (In other words, not swapping the pair of horizontal wires with the pair of vertical wires.) Or am I misreading one or both of you?

Phil Nelson

[EdKozk2]

Hi Phil,
Just reversing the two horizontal wire connections within the same circuit is what makes sense. The same would go for the vertical connections. One thing to watch for is if the picture is reversed. Lettering or words on the final viewed image will be incorrect. Just like putting a slide in a slide projector backwards.
Ed

[Josef]

Originally Posted by EdKozk2

Hi Phil,
Just reversing the two horizontal wire connections within the same circuit is what makes sense. The same would go for the vertical connections. One thing to watch for is if the picture is reversed. Lettering or words on the final viewed image will be incorrect. Just like putting a slide in a slide projector backwards.
Ed

That's exactly what I wanted to point out. Sorry for causing misunderstandings- I'm not native speaker.

[Phil Nelson]

No problem! It's a clever idea. I may get a chance to try it in a day or two.

Regards,

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

[old_tv_nut]

What type of caps and values are C-64 and C-65? If you have no way to test, substitution is surely a good idea - after all, that coil they're attached to does say H lin.