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A buddy's bg800 (was mine) is doing a weird thing. The red tube is full of what i would call video/scan noise. It is as if there were lines of noise moving up and down in the image. It causes bright and dim scan lines. I was tapping on cards, and the one (i think it was horiz. deflection) seems to make the biggest change in the noise. I took it out, cleaned everything, and checked the connectors, but the problem persisted.


The problem does occur on blue, but only slightly. Green is currently immune. I plan to borrow a card out of another bg800 to swap, but I would like some input on what is dying/dead...


By the way, it is not the 57k hour chassis that is doing this, it is the 14k chassis I bought from Curt many years ago.


Any ideas would be appreciated....


Thanks,

Garrick
 

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A few things:


1) Try a different input


2) try swapping video output cards from R to another color.


3) Does it do it with the internal test pattern?


4) The last one that had squiggly lines turned out to be a bad cap on the V board.


Curt
 

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glankford:


Did you finally found out what was the fault? I and my friend have just the same "video scan/noise" problem on BD800.

I have this scan line noise on all tubes but the red is the noisiest.

This must be quite common Barco 800 problem because my friend's barco has exactly the same symptoms.

The projector is connected to grounded outlet and I even made extra grounding to the waterpipe, no help.

I also shut down all possible devices that could cause interference to picture, still the same.

I have changed all the secondary side el-caps on SMPS and some other el-caps too, it didn't help.

My video source is Nintaus N9769 connected to barco with RGBs cable, my friend uses HTPC.

Other abnormality is that if you look at the internal testgrid you can see that the dots wiggle a bit horizontally.
 

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I noticed a similar problem on my BG800 when I first turn it on. The test pattern jiggles a bit. Sometimes it flashes an I2C error and blanks out for a second or two. And there is a black horizontal line across the screen. After about 10 minutes the picture is fine. Do you think the signal coupling caps in the RGB input board could cause the flickering and noise?


I know one time the picture got really noisy on mine, and had a smeared hazy look. The problem that time was the ground in the signal cable (vga-bnc) to the projector.
 

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I was inspecting the HV leads today because I thought that a bad contact between splitter and HV lead might cause noise.

I decided to apply some solder to the end of the lead to improve contact. At the moment the soldering iron touched the lead end the "cup" fell off! WTF? It seems that the end "cup" is only attached to the outer insulation of the lead, there is no proper contact between the lead core and the "end cup".

I'm gonna modify these lead ends today so that the leads are properly soldered to the "end cups". My idea was to drill a small hole to the cup and fill it with solder.

How about the +17V line on SMPS. If you check this line with a scope you notice that it is really dirty (heavy ripple). Does this +17V line have any influence to the picture noise?
 

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Quote:
Originally posted by JarkkoS
How about the +17V line on SMPS. If you check this line with a scope you notice that it is really dirty (heavy ripple). Does this +17V line have any influence to the picture noise?
I noticed this some time ago as well. Some people here tried cleaning it up but it didn't really help. If you look at the boards it feeds, most boards have their own voltage regulators (7805 and 7812's) right on the boards so having a noisy 17V source probably doesn't hurt that much.


If you do decide to clean it up a bit let us know what you find!


Kal
 
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