BG1209s High-Scan Hor-Def Board ringing fix?

newbieDAN

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Are any Barco gurus aware of the apparent ringing/tearing on the left side of the raster (ceiling mounted) whilst the Horizontal Deflection board is in High scan mode?(1920x1080p@60Hz)....and if so is there a documented fix, for the ringing, rather than just swaping out Hor-Def boards to one which exibits the problem least worst.
Cheers
Daniel
 
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This brings back a few memories ...

1209
 
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That looks exactly like what I'm seeing (but with more tearing in the upper left corner.....If one was to be looking for a new coil, where would one source from?
Daniel
 
I believe that coil is also common to several Barcos.
 
Will have to check but the Barco 808 and 1208 as I remember used the same coil.
 

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Would the coil HAVE to be a visibly stuffed as that one? Did yours exibit this behaviour at all scan rates or only high resolutions? Can you get the coil direct off Barco?
 
Dan I never had this problem. Bjorn did. Just kind of sounded like your description of the problem. Have you inspected the coil ?
Curt or Mad Mr H might have one if you need it.
 
I'll check the coil tonight when I get off work. Thank your memory for me:smashin:
 
PS - I have a way to reduce ring at no cost :D.

I got from 7 visible vertical ring lines down to 4 on the tube face. I have done this on several machines each with similar results - But never mentioned this as I could not be sure it would always work............

I only did this with 1209s machines BUT the principle should work with 808,1208,1209.

The 909 / Cine9 does not show this issue that I have noticed.

That combined with a slight shift of image and you don't see them.

There are also many different board versions so that is also something to note.

I have too much on at the mo, but will post with pictures.
 
Thanks Andy. Your fix would be greatly received. I'll find out what my revision number is, when I check for a stuffed coil.
Cheers again.
Daniel
 
PS - I have a way to reduce ring at no cost :D.

I got from 7 visible vertical ring lines down to 4 on the tube face. I have done this on several machines each with similar results - But never mentioned this as I could not be sure it would always work............

I only did this with 1209s machines BUT the principle should work with 808,1208,1209.

The 909 / Cine9 does not show this issue that I have noticed.

That combined with a slight shift of image and you don't see them.

There are also many different board versions so that is also something to note.

I have too much on at the mo, but will post with pictures.



Andy can you clarify this ? :cool:
 
There are now two ways to reduce the ring.

The first is my original way which I will post some photos - This is a FREE option and does not give 100% removal of the issue, and does differ between projectos as to how much it improves.

There is a second option that Greg Eisemann has now developed, I am working on getting a test board from Greg for this, I had large delivery today from Greg :D 1.3 HDMI cards for the Bad Boy Barco Blend, Silky smooth neck cards, Smoothed SMPS, Uber high bandwidth switcher and RGB cards - Watch out for my reports on Gregs most up to date HDMI input modifications :thumbsup:.

I spoke with Greg today about the ring reduction, Next delivery will include a test board for pre / post modification testing - PLEASE NOTE - I only comment on mods AFTER I have tested them myself, Part of this testing leads to the ongoing development of these products.

(Out for meal, Will look for photos when I return - Tom will still be up ;))
 
The simplist way I know of is to use a combination of H phase and Green Raster shift to bring the image away from the edge.
Playing with the width coils may help a little too

This was a know weak spot on all barcos and the Cine 9 919 etc suffer from it too but it is far less obvious. I know they worked for years for a simple fix but never really got close.
It does vary from projector to projector and board to board

Make sure Peaking is switched OFF or it will look a lot worse.

I'd be interested in what can be done. (and a time machine to go back over ALLLLLL those projectors)
 
That looks just like what marquees do at high scan rates. TSE told me he discovered while working on Split pack Marquees that the extension cables introduced massive ringing. The longer the scan cables the worse it got. he thinks if your able to shorten the cables to the deflection yokes it will reduce the ringing. Or other than messing with timings and having the raster go off the tube face to give enough time for the beam to settle down before it starts the scan of the image.

Athanasios
 
Hi Athanasios,

On my Barco I actually lessened the effect by simply working the scan switches, there are the ones which you use to select floor mount ceiling mount etc. By working the switch I mean changing the position of the switch numerous times so as to clean the contacts of any oxidation buildup, unfortunately there doesn't appear to be a way to put some cleaner into the switch. Of course it didn't fix the ringing 100% but it did clean it up a lot from the way it was previously.

After talking with Greg last year he did mention that his cure, which he said wasn't a 100% fix either, was to put another inductor in around the H amplitude coils board. One thing he didn't tell me was what value he used, oh well.

Like I say after working those switches, both H and V, you have to look very hard from the seating positions to see the ringing, or should I say be looking for it to notice it. Like TSE mentioned about shortening the lead lengths, addding switches in the line probably wasn't a good idea either but what other choice did Barco have, I never noticed how long the leads are on my 1200x, I'll have to look. The 9 series used jumpers which is a little better I suppose.

Walter
 
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Can you post a screen shot of the ringing ?
 
The ringing is so slight it's hard to see, I was just wondering if anyone had the fix so I could look at it.
 
Guys you can probably see that no one has ever come up with a definitve fix for this.
As I understand it the problem emanates from how the wire is wound or more precisely how it leave the coil. Ideally the copper wire would form a perfect circle but there has to be a point where the two ends of the wire come away. This sets up a reflection that is then seen as the diminishing ringing lines.

Some people claim that twisting or knitting the coloured scan wires reduces the issue.
I have seen claims that cleaning the contacts will have an effect. but the ringing is present in brand new projectors too

Barco did at one stage reduce the length of the scan coil wires and put the scan inversion/reversal board much nearer to the motherboard. these was not a a success and they went back to the original lay out.

as pictured earlier in this thread some of the issue are associated with the horizontal linearity coils. On high hour projectors the varnish that is used to insulate the copper wire can break down or become unstuck. Often associated with an audible squeak In order to reduce the noise I put some strong heat shrink around the coil and the volume reduced noticeably. but incidentally so did the ringing effect.

So having struck gold I decided to perform the same task on a board not making the noise. Bummer it had no effect to the ringing.
 
HI Roland,

Thanks for you breakdown of the problem. I've had my 1200x since it only had 400hrs on it and it had the ringing then too. My coils are in good shape and don't squeal. I don't think the Barcos are the only ones with this problem. Like I said previuosly, the problem isn't really that bad and I only notice it if I look for it.

Thanks
 
. I don't think the Barcos are the only ones with this problem.

No they all do it Sony Barco Electrohome. It was described as a characteristic of the technology not a fault
 

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