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Discussion Starter · #1 ·
Most noticeable on red and blue. It looks like randomly fluktuating scanlines. I use a HTPC, and an Extron RGB-118 interface. I tried a DVDO and standalone DVD-player today, but the same noise. The picture was much better fron the HTPC than from the Sony s7700/DVDO Pro combo.


Gunnar
 

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Discussion Starter · #3 ·
Thanks Rob. I`ll try that. I saw the same problem on another BG-1200 I had some time ago. Luckily I have a parts BG-1200 with all boards. I thought perhaps the RGB-input board could cause this, so I will try to replace it if it isn`t the convergence board.


Gunnar
 

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Discussion Starter · #4 ·
Rob,

Without the convergence board the noise is gone!

I replaced the convergence board with the one from my parts BG-1200, and the projector now seems to be ok! If I go close to the screen I can still see some noise, but this is probably normal? Without the convergence board even this noise is gone. Do you know which component(s) on the convergence board can cause this problem? My parts machine probably has over 20000 chassis hours, while my working unit only has about 2500.


Gunnar
 

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Discussion Starter · #7 ·
Rob,

I assume that you mean all el. caps? Maybe I`ll try that. There is a thread on replacing all el. caps in the RGB-signal path on the BG-800, se http://www.avsforum.com/avs-vb/showt...ht=bg800+caps. This mod regards the RGB-input modele, quad decoder, and RGB-output module. I would be interested in trying the same on the BG-1200. But what about the convergence module? It isn`t in the RGB-signal path (as I understand it..), but seems to influence the noise level alot anyway?


Gunnar
 

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Hey Gunnar!


Gerni & myself started that thread about replacing BG800 'lytic caps in the RGB signal line with very high quality Jelmax Black Gate caps so it's a bit different...


I'd check the 'lytic caps on the convergence module for shorts and leaks as well as the cap's ESR if you have a meter to do this. It should also help your convergence stability.


Kal
 

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hi kal,


are the bgs still in your 800 or out?

mine improved over time alot. had a huge amount ordered and all soldered in, but no time to put the new boards in.

one unbelieveable thing happend when i modded my linn ikemi cd player with the bgs: the noise in the analogue sat was reduced by 80%.

i can not explain this, cause the cd got nothing in common with the video except the same dedicated power line. what i think, the bgs are now burned in.

did the controller and pll, the rgb quad decoder, most of the vertical deflection and the smps on the primary side, all with f and n-types. also replaced the first 400uf with 2x 150uf nh type in l-cancelling.

for all boards the setup has to be done new, this will take too much time before christmas vacation. have to wait ´till beginning of 2003.

plans for january are finishing the vertdefl. and the convergence board, also the eht module with a wkz type.

last will be the secondary side of the smps and the hordefl and n-s corr. + the fraim. but before, i will definitly buy a new blue tube.


hope your smps will soon work again!

good luck.


g.
 

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Wow Gerni! Sounds like you're pretty much replacing every single 'lytic cap in your BG800 with Black Gate's!


Mine are all out except for the 6 on the R/G/B lines in the RGB input board - those are the ones that made the biggest difference for me.


I took the others out because they made the hum-noise problem I have more obvious. Hopefully this noise problem was SMPS related and fixing the SMPS will get rid of it..... we'll see!


Once I get the BG800 up and working again, I think that I'm just going to sell it and upgrade though... Possibly a Marquee 8000 or a BG808/1208. We'll see what works out.


Kal
 

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hi kal,


yeah, i´m blackgateystic.

i found that the bgs in the output module gave improvment a big step.

as much as in the input board.

the noise is common for barcos?!

without the bgs, i saw some sort of strange scanlines, most noticeable in bright scenes, but after close examination this is ordinary NOISE.

let´s see what happens after installing the part-noisefree smps.


modded yesterday an ampro g2600 inputcard. 1st and 3rd section.

was a blast! my friend is very pleased with the improvement.

we took the whole afternoon running different resolutions, up to scan max of the pj. no noise at all.


what i also noticed on my bg800 is problems in syncing from pal to ntsc.

one time it displays ntsc right away, the other it needs 2-5 attempts.

furthermore it displays blinking or rolling black thick lines in both top corners and sometimes in the left bottom corner. half times it disappears after a couple of minutes or it will get worse right away, showing a screen that gets darker and darker. this is also with standard boards.

the barco tech never heard of such a thing.

did you?


bye,


g.
 

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Never heard of such a thing Gerni! I'm in NTSC land and only switch between 720p/60Hz (HDTV) and 720p/72Hz (HTPC DVD). Never had problems with switching.


About the RGB output boards - yep - I noticed a big jump in clarity when I replaced the caps with Black Gate's. Too much clarity in fact, that I really noticed the noise and found it very distracting, so I had to take the Black Gate's out.


Kal
 

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Discussion Starter · #13 ·
Mike,

I will post my findings if I do this. I think I will start with the convergence board, as the noise was almost nil without it. I have the service manual, and will take a look at the circuit diagram to try to locate the parts that may cause this noise.


Kal, Gerni,

I read your thread with interest. I had a BG-800 some time ago, and I did som repair on the RGB-input board. It is almost the same as on the BG-1200. It is single sided as on the BG-800, so it is easy to replace components. I also have a BG-801s, and on this machine the board is double sided. All the boards look a lot more "finished", without all the modifications/upgrades everywhere. Also SMD-components.


Gunnar
 
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