Need VCRs with video stabilizers

[Alwyn]

But is that really kind rude??

Yes.

[Litaiff]

@timtape Did you see the 2 vids I uploaded?

[Litaiff]

But is that really kind rude??

Yes.

[Alwyn]

I didn't mean to be narky, sorry. You do not need to post in bold. It is considered shouting. We're not that old that we can't see forum normal, unbolded text.

[Sharc]

Just guessing that the OP wanted to tell us that he has problems with his eyesight. That's ok then.
He doesn't have to worry about other users eyesight though. They can enlarge fonts as needed.

[Alwyn]

the OP wanted to tell us that he has problems with his eyesight.

@Litaiff, If this is the case, I profusely apologise. I thought you were bolding for our benefit.

[Litaiff]

@Litaiff,[/B] If this is the case, I profusely apologise. I thought you were bolding for our benefit.

It's okay with me, but I was really thinking about you guys, since in one of my first posts here, on another account, there was someone who didn't quite understand what I wrote, and I had to mark him to read it again, so, since then I've been using bold, but okay, I'll use the normal text then.

[Litaiff]

Hello. Still talking about the manual alignment I did on this device's audio head. I'm very pleased. The SP tapes are great now, and the stabilizer works perfectly. Although the EP tapes aren't completely stabilized, I was just a little short of aligning them correctly, but I decided not to mess with them anymore.

So, I ask the to experts. Is there a way to do this, to align 100% everything correctly? So I can play the EP tapes as well? Some kind of special tape to achieve this 100% alignment? Remember, I didn't touch the guides, just the audio head screws.

[timtape]

EP tapes will be more difficult than LP or SP because the recorded picture tracks are narrower, That means more "noise" in the picture. Also it's more likely the video heads will not fully read the picture track from top to bottom of the screen. As well, the standard audio will be poorer because tape speed is slower. There are calibration tapes but we cant assume all recordings were made to all calibration standards.

Screws 2 and 3 on the A/C head have a dual function. They adjust both the height of the head re the tape, and the "tilt" of the head. Adjusting this "tilt" can be difficult. We dont adjust this with a tape but visually, comparing it with a physical reference inside the machine. Again the procedures are in the service manuals. Sometimes special tools are needed. Once screws 2 and 3 are adjusted properly, they dont normally need adjustment again until the head wears out and needs to be replaced.

Screw 1 is less complicated. We adjust screw 1 and only screw 1 for the clearest (linear) "mono" audio on the tape we are playing.

Again there is no set of calibration tapes which will make every tape play at its best because there will be some tapes recorded on machines which were not fully calibrated to the standards at the time of recording.

[lordsmurf]

I'm just writing in bold here because I know there are people here with already pretty bad vision because the age, like some VHS experts. But is that really kind rude??

FYI, bold actually makes it harder to read, not easier.

There is a middle ground between light whispy fonts, and thick bolded fonts, and it's called "medium" typefaces. A lot of these sans serifs are too thin, the bolded versions too thick. Medium sans serif fonts often have both thick and normal thinner elements, such as Open Sans or Franklin Gothic.

[Litaiff]

Thanks @timtape for your answer


...but now a possible image problem has arisen with my JVC HM-DH30000U. I'm asking for your help again to resolve it. Maybe it's a very simple problem

Here's the thing.

After successfully restoring the video stabilizer on the Philips VR999 (SP tapes only), simply by adjusting the audio head screws, I decided to adjust the audio alignment of the JVC HM-DH30000U. I also suspected that the previous owner had tampered with something, as the video stabilizer wasn't working perfectly.

Furthermore, the day I went to pick it up, at a Catholic building, a Jesuit priest who was bringing it dropped it. There were two devices, but only this one worked normally. Until then, I thought the video stabilizer was fine, but after playing several tapes, I noticed a certain "shakiness" on some tapes when the stabilizer was on. So I only used it for good tapes; with the stabilizer off didn't cause the "shaking."

After manual adjustment, just by adjusting these three screws (Pic 01) and testing with an SVHS/SP, VHS SP, or VHSC EP tape, I got some improvements, almost 100% in the video stabilizer, and the audio is much clearer now, as in the example video I left here.

I also left a video example showing how the stabilizer was working poorly before, and now after the adjustment it's much better. But of course, I'm not a technician; I did it manually, just listening through headphones connected to the VCR and watching the TV screen, and also with the help of the youtuber @12voltvids.


The problem:

After all these adjustments, I ran some capture tests and then a frame analysis. I noticed that before the video signal had a slightly clearer and more defined image (Pics 02, 03, and 04).

In pics 03 and 04, I split the subject's face in half, the before and after, in the microphone the separation is more visible.

Now, after the adjustments, with the stabilizer working almost 100% and with the audio being much clearer, but it has this almost imperceptible color problem and slightly worse definition.

I want to fix this because I've already made the video stabilizer work much better and the audio much clearer, but the fact that I modified the image and made it a little worse with less sharpness and a little darker has left me frustrated.

The capture sources I used are the same, the same cables, the same outputs and inputs, the same capture device, the same JVC settings, nothing has changed.

So I conclude that it was because of the adjustments I made to the audio head that made it better in both aspects and worse only in the generated video image.



[Attachment 89295 - Click to enlarge]

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[aramkolt]

I'm going to have to guess that the tapes you are converting don't have HiFi (stereo) audio? If they do have HiFi, generally adjusting the audio head won't change much other than the tape tension and perhaps the tape path a little. For mono linear audio tapes, moving the audio head will make a pretty big difference, but the downside is that the range that it is best on most tapes is pretty sensitive.

As far as what you can do now, best bet would be to look at the RF envelope with an oscilloscope to get it as flat of waveform as you can, or if it is already flat, I wouldn't adjust anything.

In terms of difference in picture clarity from one capture to another, moving the audio head could have changed the tape tension or the tape path alignment, but the only way to really know if that's the case is to look at the Video RF waveform as noted above. It could be if the stabilizer is needing to do "more stabilization" that the picture gets blurred some degree during that process and that might be the case if the alignment has shifted. Generally, higher tape tension will produce a better picture, but at the cost of being harder on the tape itself, heads, and the rest of the transport. On a tape like this where there are no obvious dropouts, I wouldn't look into increasing the tape tension. Sharpness can vary a lot from VCR to VCR and I don't know that the D-VHS machines are particularly well known for sharpness during playback of analog tapes if that is what you are looking for.

[Litaiff]

I'm going to have to guess that the tapes you are converting don't have HiFi (stereo) audio? If they do have HiFi, generally adjusting the audio head won't change much other than the tape tension and perhaps the tape path a little. For mono linear audio tapes, moving the audio head will make a pretty big difference, but the downside is that the range that it is best on most tapes is pretty sensitive.

As far as what you can do now, best bet would be to look at the RF envelope with an oscilloscope to get it as flat of waveform as you can, or if it is already flat, I wouldn't adjust anything.

In terms of difference in picture clarity from one capture to another, moving the audio head could have changed the tape tension or the tape path alignment, but the only way to really know if that's the case is to look at the Video RF waveform as noted above. It could be if the stabilizer is needing to do "more stabilization" that the picture gets blurred some degree during that process and that might be the case if the alignment has shifted. Generally, higher tape tension will produce a better picture, but at the cost of being harder on the tape itself, heads, and the rest of the transport. On a tape like this where there are no obvious dropouts, I wouldn't look into increasing the tape tension. Sharpness can vary a lot from VCR to VCR and I don't know that the D-VHS machines are particularly well known for sharpness during playback of analog tapes if that is what you are looking for.

All the tapes I used had hi-fi audio. I don't understand the RF envelope part, but I'll look into it. Remember, I didn't touch the guides, just the three screws on the audio head.

To fix this slightly darker and less clear image, wouldn't it be possible to simply try moving the screws again? Or just one?


Another image of how it looks now, comparing a VHSC in EP before and after.


[Attachment 89313 - Click to enlarge]

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I know it's not that bad, but it bothers me, I would like to solve it, because I was satisfied with the audio and the stabilizer working much better.

[Litaiff]

Another thing, I have 5 S-video cables. I don't remember which one I used first; they're all the same. Should I also test each cable individually? Perhaps one of them produced a sharper, clearer image?

[Sharc]

Another thing, I have 5 S-video cables. I don't remember which one I used first; they're all the same. Should I also test each cable individually? Perhaps one of them produced a sharper, clearer image?

Loss of sharpness is possible if a cable (Y wire) has a poor frequency response, means attenuating high frequencies unduly.

[Litaiff]

Another thing, I have 5 S-video cables. I don't remember which one I used first; they're all the same. Should I also test each cable individually? Perhaps one of them produced a sharper, clearer image?

Loss of sharpness is possible if a cable (Y wire) has a poor frequency response, means attenuating high frequencies unduly.

Hi there.

So, I tried swapping all the cables and the image is still darker and less sharp.

[Attachment 89370 - Click to enlarge]



If anyone can help me, what should I do next?
Since I don't have any testing equipment, I'll have to do it by eyes.
Could the solution be related to one of the three screws I adjusted?

[timtape]

You should not have turned those three screws without understanding their purpose. Normally the only screw that can safely be adjusted by an unskilled person is the Azimuth screw (2) as in the diagram taken from the Service Manual. This only finely adjusts the clarity of the Normal (linear) sound track. It is not for adjusting the Hi Fi Stereo track or anything else.

It's always a good idea to ask first before jumping into the deep water.

[Litaiff]

@timtape

Yes, I did that, but as I mentioned, I managed to stabilize the video and made the sound clearer... But according to your diagram of the screws, which one should I adjust again to try to make the image clearer like it was before?


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[rgr]

Another thing, I have 5 S-video cables. I don't remember which one I used first; they're all the same. Should I also test each cable individually? Perhaps one of them produced a sharper, clearer image?

1. It's best to check cable quality with a test image—for example, JVC produces a nice blue image that shows any interference. You can capture this image on each cable and then increase the contrast on your computer until you see the differences between the cables.

2. Remember that VCR automatics can adjust to the tape differently each time, and you can sometimes get a slightly brighter or darker image on the same tape. The same applies to audio.

[Litaiff]

Another thing, I have 5 S-video cables. I don't remember which one I used first; they're all the same. Should I also test each cable individually? Perhaps one of them produced a sharper, clearer image?

1. It's best to check cable quality with a test image—for example, JVC produces a nice blue image that shows any interference. You can capture this image on each cable and then increase the contrast on your computer until you see the differences between the cables.

2. Remember that VCR automatics can adjust to the tape differently each time, and you can sometimes get a slightly brighter or darker image on the same tape. The same applies to audio.

Yes, what you said is exactly what I did; I tested one cable at a time, and they all resulted in less contrast and sharpness in the video. I really only wanted to adjust those screws again if I knew the color would go back to how it was before. The fact that it's darker than before is what bothers me, but I'm happy that I managed to stabilize the video and that the audio signal improved. Wouldn't the solution for the color issue be to adjust screws 01 and 03 again?