Motorola roundie

[old_tv_nut]

I'm surprised that only one adjustment was needed.

With the fixed matrix resistors, you can adjust I/Q relative phase and the COLOR control to compensate for errors in one color matrix, say red. Then you still need I and Q gain adjustments in both green and blue to get them perfect, so that's four additional adjustments total.
If you insist on the I and Q waveforms being exactly correct, then you need I/Q ratio adjustments for errors in all three matrices, plus luma vs chroma gain adjustment in two of them, so that's five additional adjustments.
As you say, these adjustments can be avoided by the use of precision resistors in the matrices.

[old_tv_nut]

By the way, back when I did an analog IC chroma demod/matrix design at Zenith (to provide RGB outputs for the unitized-gun CRTs), I had to use some (lousy) on-chip vertical PNP transistors in the color difference paths, and it was necessary to do a statistical analysis of the component matching of those as well as the matrix resistors to show that the 95% ellipsoids of color variation were not significant.

[Alex KL-1]

Originally Posted by old_tv_nut

Actually, modern flat screens have much better color than the old CRT sets, IF you turn off the "lighthouse" default sales-floor mode and set them to a calibrated mode. This is especially true because of the much better contrast (consistent, blacker blacks) of flat panel sets.
This was not true with the very early flat sets because makers had not gotten the hang of compensating the extreme non-linearity of LCDs to match the ideally smooth non-linearity of CRTs.

Well noted about the sales-floor mode. Even OLED comes with some saturated thing to catch the consumer... in my OLED, I apllied only well-carefully adjust settings. It also have 100 point adjusting, like the LCD, for shaping the display curve response.

But then, we can calibrate a CRT device for true black levels and great contrast, but is more challenging due to simplified nature of the beast.
More modern CRT TV having "AKB" will stabilize the black point and color balance, and produces outstanding contrast picture with true black at same time, only seen in OLED TV's, since OLED are emissive display like CRT, with the advantage of independent asembled pixels free of focus, halation and moiré effects.

But, in the end, owners of the calibrated CRT will challenge this contrast issue, at least for very contrasted scenes: the light leaking from LCD and alike (LED, QLED) interferes with the result: one black image immediately adjacent to a white block will have light leaking (gray result). The CRT with black matrix will have a very dark result at same scene, and OLED completely dark.
I seen it even in hi-end QLED, even in the letterbox bar, when not coincides to light zone. In my aforementioned CRT TV, and in my Sony CRT monitor, I'm able to achieve 100% black here, and also abvously in my OLED TV.

And, the run-of-the-mill LCD have very noticeable light leakage even in today models, but consumer are used to it.

[Alex KL-1]

Originally Posted by dtvmcdonald

I would not say that the color itself of the new flat screens is much better.
It is the basic light intensity curves, which are obvious in B&W. The perfection of gray scale if of course better too. That's because they are all adjustable ... but most people don't do it. And in many cases the default so-called "correct" setting is artificially far to dim (to match the default too-dim screens of movie theaters).

I can and have gotten my old Sony Bravia and my CT-100 to be essentially perfect matches by adjusting the Sony gamma to match that of the CT-100,
which is not ideal. IF you adjust the Sony to the correct gamma, you can get either mid-tone hues to match, or high-tone hues to match, but not both at once. This is with the Sony hues correct. I can do the same with my high-end Dell "Photoshop edit" monitor. This is with the one additional adjustment I added to my CT-100 color matrix, which gives complete control. The correct setting is within the standard resistor tolerances, but noticeably off the nominal value.

The difficult hues are in the yellow vs yellow-green and purple vs. violet areas.

And, in the transmissive displays, the color converges to gray at low light scenes due to light leakage (loses color space). Is more obvious when compare against OLED.

Granted is the better quality on newer panels, allied with 100-point adjusting and internal processing. But is amusing to compare that very refined and advanced device against a simple and humble CRT color TV using all tube tech... if we consider all differences, is a miracle the results achieved by the old techs

[dtvmcdonald]

Originally Posted by old_tv_nut

I'm surprised that only one adjustment was needed.

With the fixed matrix resistors, you can adjust I/Q relative phase and the COLOR control to compensate for errors in one color matrix, say red. Then you still need I and Q gain adjustments in both green and blue to get them perfect, so that's four additional adjustments total.
If you insist on the I and Q waveforms being exactly correct, then you need I/Q ratio adjustments for errors in all three matrices, plus luma vs chroma gain adjustment in two of them, so that's five additional adjustments.
As you say, these adjustments can be avoided by the use of precision resistors in the matrices.

I'm not thinking as hard as I did when I actually did it.

I though about getting the signals right at the CRT.

First consider B&W, color turned off. Brightness sets black level for one color. the CRT brightness controls the other two black levels. Contrast and the blue and green video gains controls the peak brightness of the three CRT guns.

Thus the three B&W matrix resistors are arbitrary but now considered fixed.

There are six color matrix resistors. There are these color adjust controls:
Color saturation, user hue, I-Q phase difference, and I gain.

Hmmm ... unless I screwed up today, it looks like I needed two more adjustments rather than just one. But in any case, adjusting just one
of the matrix riesistors got it essentially correct.

In another view there really need to be two or three more adjustments, but there's no easy way to do these . Those are adjustments for the three gammas of the three CRT channels. Of course the relative settings of the three screens and the two video gains can do a bit of this, as could adjusting the fraction of DC restoration (R249/R273/R274 values, etc.) in each of the three channels (its intentionally not 100%).

Edit: There is one "gamma" tuning that RCA made, and that is the 2.7K resistor in the red CRT cathode. This may also be there
to save it from overdrive in grid conduction ... which is awfully easy to do!

On my set I have added little red and blue masking tape arrows to the brightness, contrast, hue, and color level controls.
The blue ones are my chosen "correct" settings, while the contrast, color level, and brightness have red ones that are placed
so that if I don't exceed them (with the others set at blue) there is never current through that 2.7 K resistor. If there IS current
through it, the CRT red cathode and red DC restorer clip both positive and negative red levels. These red arrows are placed
by using my scope in subtract mode with the DC level and gain of the inverted scope channel so there is zero deflection
with the two probes on the same side of the resistor.

[timmy]

This Motorola I have has a faint white line 12 to 6 straight up and down position any thoughts how to fix this or troubleshoot.

[Yamamaya42]

Weakness or imbalance in the horizontal output tubes may do it, this moto is an odd set with the pair of 6JM6s.

[timmy]

Originally Posted by Yamamaya42

Weakness or imbalance in the horizontal output tubes may do it, this moto is an odd set with the pair of 6JM6s.

Well the tubes are new and I had the same line on the cbs Columbia and a slight adjustment of the horizontal frequency pot the line disappeared

[Yamamaya42]

Originally Posted by timmy

Well the tubes are new and I had the same line on the cbs Columbia and a slight adjustment of the horizontal frequency pot the line disappeared

My Stromberg Carlson X22 had the same sort of thing happen, faint white line when started, that would slowly fade after 20-30 min, caused by a weak/tired 6CU6 (11w max)
This went away after it was replaced with a slightly stronger 6GW6 (17.5W max)

Not sure if this is the same as your problem, but it may be similar symptom.

[timmy]

Is there a specific type of antenna for this Motorola color to get a clear picture because rabbit ears don’t seem to work well being it’s color maybe there should be an antenna specific to color

[old_tv_nut]

Originally Posted by timmy

Is there a specific type of antenna for this Motorola color to get a clear picture because rabbit ears don’t seem to work well being it’s color maybe there should be an antenna specific to color

What channel are you using?

There really is no specific "color" antenna, just as there's no such thing as a "digital" antenna. Generally an antenna is good or bad depending on the specific channel for both black and white and color.

[timmy]

Originally Posted by old_tv_nut

What channel are you using?

There really is no specific "color" antenna, just as there's no such thing as a "digital" antenna. Generally an antenna is good or bad depending on the specific channel for both black and white and color.

Using channel 3 putting cable signal in an antenna amplifier and output has an antenna and all my sets work and the color but it not clear

[old_tv_nut]

Low VHF is not the best for indoor antenna rabbit ears, as they are generally too short for the wavelength. If you can use high VHF or UHF you may get better results.

[timmy]

I have an antenna 15 feet any from the set so what do you mean by a high vhf antenna or channel

[Yamamaya42]

Channels 3-4 are best avoided if used over air, as RFI plays havoc with that range, direct RF coax should be OK for 3-4, but over air will always be a pain, I have a BT modulator that outputs on channel 7, which is a lot clearer, but 11-12-13 would be even better.