Motorola ts907 low hv

[timmy]

Originally Posted by dtvmcdonald

Well well well! That proves that each and every part of the set works.

Interestingly, the color bars from bottom up (orange up) are + and - I then
- and + Q.

Where does that test pattern come from? What DVD?

PM5544 find it on line take a picture on the computer then burn the image on a dvd that’s what I did. While it may look good on this set it’s not because red is not exactly red the colors are not there yet. Kind of not understanding while the colors look ok they seem to be in the wrong place and not exactly what the pattern shows maybe because it’s a digital image.

[dtvmcdonald]

I found the original.

The image on your TV set has a seriously wrong "red" or "magenta" bar. The exact nature of the problem ... undersaturated ... is very frequently
that the main video carrier is at an improper spot on the IF response slope.

I strongly suspect that all your set now needs is a full IF and possibly but less likely also RF alignment, and getting the AGC working right. The AGC won't work
right unless the video carrier is at the right spot on the slope.

The CTC-5 at the ETF which I worked on last spring has the exact same
problem.

You seem to be a patient person. Its perfectly possible to align a TV
with nothing but a plain signal generator and an analog voltmeter! Just
use the bias box you already have to override AGC and meter at the
video detector, plain DC. You can in a pinch even use the second harmonic
of the oscillator of a SW radio, you just have to take into account of that
oscillator's (typically 455 kHZ) offset from the dial. I've actually done that
in a pinch!

[timmy]

Originally Posted by dtvmcdonald

I found the original.

The image on your TV set has a seriously wrong "red" or "magenta" bar. The exact nature of the problem ... undersaturated ... is very frequently
that the main video carrier is at an improper spot on the IF response slope.

I strongly suspect that all your set now needs is a full IF and possibly but less likely also RF alignment, and getting the AGC working right. The AGC won't work
right unless the video carrier is at the right spot on the slope.

The CTC-5 at the ETF which I worked on last spring has the exact same
problem.

You seem to be a patient person. Its perfectly possible to align a TV
with nothing but a plain signal generator and an analog voltmeter! Just
use the bias box you already have to override AGC and meter at the
video detector, plain DC. You can in a pinch even use the second harmonic
of the oscillator of a SW radio, you just have to take into account of that
oscillator's (typically 455 kHZ) offset from the dial. I've actually done that
in a pinch!

What is exactly the main video carrier are you referring to the rf modulator with DVD player or in the IF strip. what would I do at the detector measure voltage from what to what ? All I have is a tuner subber.

[dtvmcdonald]

By video carrier I mean the main carrier of the RF signal ... 1.25 MHz up from the
bottom frequency of the channel (at RF .... down from the top at IF).

But if you don't already have something suitable as generator .... There's got to be
somebody near you who can loan you one and show you even a bit how to use it.
I'd do that if I were not 1000 miles away.

Doug

[Yamamaya42]

Originally Posted by dtvmcdonald

By video carrier I mean the main carrier of the RF signal ... 1.25 MHz up from the
bottom frequency of the channel (at RF .... down from the top at IF).

But if you don't already have something suitable as generator .... There's got to be
somebody near you who can loan you one and show you even a bit how to use it.
I'd do that if I were not 1000 miles away.

Doug

yeah, they are not cheap

i got this a year or so back to align my BW Arvin TV.
https://tinyurl.com/24atccvt

[timmy]

Originally Posted by Yamamaya42

yeah, they are not cheap

i got this a year or so back to align my BW Arvin TV.
https://tinyurl.com/24atccvt

So what exactly does this unit do ?

[timmy]

But if I was to get that pattern perfect color wise does that mean color in video would be good also.

[dtvmcdonald]

Originally Posted by timmy

But if I was to get that pattern perfect color wise does that mean color in video would be good also.

Probably, assuming the video connection was done correctly.

[Yamamaya42]

It's a multifunction RF signal generator that goes up to 60 mhz, does sine wave, square-wave, Triangle half, and many others, sine wave in the 40 mhz range is what is needed to do TV alignments with exact control. Which what this has be cause you can set the freq and amplitude.

[Electronic M]

If all you are doing is setting the tint/hue you want color level to be fairly low. If you have color level too high and overdrive the demodulator you'll get distortion in the demodulate hue...It's also important to have purity good before trying to watch or adjust color...I once drove myself mad for a few hours trying to figure out why the yellow bar on a SMPTE color bar pattern was wrong on a Zenith despite all other bars being right....After chasing my tail I gave up and dialed in the purity and suddenly yellow was as perfect as all the other bars.

[timmy]

The red is not where it should be but the pic is better then the last one. Purity is good got white screen.

[Electronic M]

Originally Posted by timmy

The red is not where it should be but the pic is better then the last one. Purity is good got white screen.

Besides the diagonal interference it looks good to me. The magenta/red aren't perfect, but I've watched worse.

[timmy]

Originally Posted by Electronic M

Besides the diagonal interference it looks good to me. The magenta/red aren't perfect, but I've watched worse.

Well I got it even better but tv video only has color lines running across the screen it’s not locking in.

[timmy]

This is a running video fed to the antenna input of the tv why is the video playing with perfect color but I put the cable wire on and this is what I get. What is the difference between the dvd and rf modulator and cable.

[Electronic M]

It's possible your DVD has higher color level on it's output and is overdriving the demodulator in the TV.

The main difference I see between the last 2 pictures is loss of color sync (barberpoling) in the second picture.
You fix babrberp the way I described earlier by adjusting the chroma osc transformer with a color bars test pattern and color level maxed and fine tuning set for the worst position that gives recognizable color/barberpoling, and adjust color osc to achieve sync under that worst case scenario so that it syncs very easily under better fine-tuning/signal conditions.