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jsternbe
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Post subject: Laserdisc noise - What might be causing it? Posted: 21 Sep 2019, 14:48 |
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Joined: 25 May 2016, 13:54 Posts: 10 Location: United States Has thanked: 0 time Been thanked: 0 time
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My LD-S1 has started to produce this strange noise in the picture that looks like horizontal lines. I suspect that it might be a capacitor that went bad, but I am not sure. Has anyone seen this happen before and know what section of the player I might look to try to fix it? I am handy with electronics and I have the repair manual, but if someone knows where to look first, it would speed up the process of fixing it. James Sternberg
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jsternbe
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Post subject: Re: Laserdisc noise - What might be causing it? Posted: 22 Sep 2019, 02:56 |
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Joined: 25 May 2016, 13:54 Posts: 10 Location: United States Has thanked: 0 time Been thanked: 0 time
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I don't plan to open the player at all unless I can figure out what is going on. I'll fix my old HF9G before I mess with it, but I do wish I could figure out what is going on here. Here is the output with no disc inside, and you can see the effect at the edges. This pretty much eliminates any laser or alignment issue. I've replaced the cable, but I get the same thing. I looked at old encodes, and it looks like the problem began a few weeks ago, but it has gotten a bit worse over these two weeks. I have tried a different outlet in case there is dirty power, but what I haven't done is move it to another room to see if there is something around here producing enough RF to cause this distortion. It looks like there are approximately 150 of these lines (I keep losing count), so if a full frame is 1/30th of a second, it would have to be something about 450 Hz (or some multiple if there is aliasing). Oh well, hopefully someone will have run across this before. rein-o wrote: I think its more like interference rather than adjustments as it looks like old antenna issue but I'm no tech. Whatever you do PLEASE make sure 100% that you figure it out before you start tweeking stuff as those players have NO PARTS and they are very good players.
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jsternbe
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Post subject: Re: Laserdisc noise - What might be causing it? Posted: 22 Sep 2019, 04:20 |
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Joined: 25 May 2016, 13:54 Posts: 10 Location: United States Has thanked: 0 time Been thanked: 0 time
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I don't think it is a computer issue either. It is still there when I turn off the computer and it is going through a monitor. It did get better messing with the cables, but it is still there. It could be a cable issue, or it could be something as simple as the connection to the RCA jacks being bad, causing an impedance mismatch. I'm not really sure at this point. rein-o wrote: Oh sorry I have no idea on what to do running this through a computer or other device rather than just TV. Hope someone else can help.
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jsternbe
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Post subject: Re: Laserdisc noise - What might be causing it? Posted: 23 Sep 2019, 00:27 |
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Joined: 25 May 2016, 13:54 Posts: 10 Location: United States Has thanked: 0 time Been thanked: 0 time
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It does scroll, and I know that I have grounding problems in my place, but I thought I had it fixed. Basically the cable TV is on a different ground than the electrical system and it causes a ground loop. It used to make my computer speakers buzz, but I managed to isolate that loop. Anyway, I changed out some more cables, switched some things around, changed outlets, etc. and now most of the noise is gone. I might need to invest in a second power conditioner for the equipment on this side of the room (the regular AV system already has one). ldfan wrote: If what I am seeing is something I call the “Venetian blind effect”, it was common when using an RF out connection of a VCR or LD player that had an RF out and would only show up when used with an RF channel that was also being broadcasted (e.g.: at the time, ch 4 was the active analog OTA channel in my area so I always had to use ch 3 which was not active to avoid the effect). But anyway, I’m sure that is not it since we don’t get this particular issue these days. Moving on....
In any case, can you tell me if these lines remain stable or does it appear to scroll up and down in various speeds? If it does scroll, my best guess is that you could simply have some bad grounding somewhere or getting some ground loop issue. Have you made any changes to your set-up recently like add a new Cable service to your home that required some new cable installation that required a new GND post to be made to your home? I know this sounds like an odd thing to inquire but you’d be surprised what interference we can get when an electrical and Cable ground don’t match up properly.
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jsternbe
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Post subject: Re: Laserdisc noise - What might be causing it? Posted: 23 Sep 2019, 20:46 |
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Joined: 25 May 2016, 13:54 Posts: 10 Location: United States Has thanked: 0 time Been thanked: 0 time
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It is a two prong polarized plug. I don't think that it is AC noise, however. A ground loop would be 60 Hz here in the US, and that was part of the point of NTSC being 29.97 fps. It looks to me by the number of lines that it is much higher frequency than that (about 450 Hz). Still, I might buy a Hum X and see if that works. ldfan wrote: Can you also tell me if your LD-S1 has a three prong outlet? Can't remember if it did back in the day when I was selling this stuff.
If so, I would temporarily use a three to two prong AC plug adapter so you can isolate the GND pin on the plug and see if that might work as well to break the GND loop. Keep us posted on what else you find.
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