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TbX
Joined: 06 May 2006
Posts: 94
Location: Sweden
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| Posted: Mon Nov 02, 2009 1:53 am Post subject: video noise |
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Hello all
I have a lot of noise in the image on my BG1209s
I did not see as much of it before I switched to LUG tubes and HFQ900 lenses but now it disturbs me
There's lots of mods to marqee so it ought to be some for barco also
//TbX
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Mon Nov 02, 2009 2:36 am Post subject: |
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On the Marquee's we found out that the Carbon composition resistors in the HVPS, LVPS and Video neck boards are noisy, we swapped them out with ceramic resistors from ohmite, carbon film could also work but not as good. Metal film might be too magnetic for some areas like the neck board and HVPS. Do some research on what is best
with different types of resistor materials. You could go ultra high end and use tantalum resistors, I never tried them but I might soon, expensive though at 9 bucks a resistor.
But on my new marquees 2004 build there is more noise than from my Marquee's i have modified the HVPS and VNB's with ceramic Ohmites.
Athanasios
_________________
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"Republicans believe every day is the Fourth of July, but the Democrats believe every day is April 15." --- President Reagan
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Marquee High Performance Bellows now shipping!!
Marquee Modifications and Performance Enhancement
Marquee C-element and Bellow removal
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TbX
Joined: 06 May 2006
Posts: 94
Location: Sweden
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| Posted: Mon Nov 02, 2009 9:05 am Post subject: |
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it sounds interesting, I may take a power supply and start looking
what are the rails, I shall focus on
//TbX
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Mon Nov 02, 2009 11:03 am Post subject: |
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| TbX wrote: | it sounds interesting, I may take a power supply and start looking
what are the rails, I shall focus on
//TbX |
There is no Carbon composition resistors in Barco smps. In neck boards there is fife or so per board.
What is your source and is that noise there only with movies or also with test patterns? (film grain in HD movies or actual video noise)
Have you adjusted G2 and brightness correctly after tube swap?
Do you use some gamma boost device?
These affect how clearly video noise can be seen in dark scenes.
I have added similar power rail filtering to driver board and to neck boards what input board have from factory.
Maybe I test those neck board resistors some day, but I doubt that those make wonders. Those hadn't much effect in my 801s and I don't have problems with noise in my BG808s right now. (same video chain what your 1209s)
But maybe after working low level gamma boost solution, it's needed to test those ohmites also in BG808s...
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TbX
Joined: 06 May 2006
Posts: 94
Location: Sweden
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| Posted: Mon Nov 02, 2009 11:11 am Post subject: |
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it is evident on both the internal testpattern and video
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TbX
Joined: 06 May 2006
Posts: 94
Location: Sweden
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| Posted: Mon Nov 02, 2009 11:19 am Post subject: |
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| Ile wrote: |
I have added similar power rail filtering to driver board and to neck boards what input board have from factory.
Maybe I test those neck board resistors some day, but I doubt that those make wonders. Those hadn't much effect in my 801s and I don't have problems with noise in my BG808s right now. (same video chain what your 1209s)
But maybe after working low level gamma boost solution, it's needed to test those ohmites also in BG808s... |
but how was your mods do they result in visible difference
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Tue Nov 03, 2009 9:02 am Post subject: |
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| TbX wrote: | | but how was your mods do they result in visible difference |
Hard to say, because I didn't much testing before I made those chances and also swapped tube type from Sony to MEC at same time. Made those line filters because I had already advised those chances to my friend driver board, so I had "design" ready. He was pretty happy with result in his BD808s, but he had different neck boards and I removed abl from those at same time. So I don't have straight answer for you, but there is good chance you notice difference. 
Those are pretty easy chances if you want to give a try. Caps and inductors are pretty cheap and easily available from ELFA.
Ohmite resistors need to be ordered from farnell and cost much more.
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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| Posted: Tue Nov 03, 2009 9:26 am Post subject: |
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Did you add the resister to pin 7 (KH1) of the LUG's ?
| Description: |
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Download |
| Filename: |
CRT_base.pdf |
| Filesize: |
29.37 KB |
| Downloaded: |
251 Time(s) |
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TbX
Joined: 06 May 2006
Posts: 94
Location: Sweden
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| Posted: Wed Nov 04, 2009 3:00 am Post subject: |
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@ tom
on my necboard it looks like pin 7 is to ground
I will probably try a resistor there instead
@ile
do you have pictures of how you mounted your filters
//Tbx
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Wed Nov 04, 2009 1:50 pm Post subject: |
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| TbX wrote: | | do you have pictures of how you mounted your filters |
Not yet, but can take some pictures if you are interested.
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TbX
Joined: 06 May 2006
Posts: 94
Location: Sweden
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| Posted: Wed Nov 04, 2009 7:59 pm Post subject: |
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yes thanks it would be appreciated
Always interesting to see how others do their mods
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Thu Nov 05, 2009 1:56 pm Post subject: |
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I have one stock neck board without mod and I tested it in my 808s last night with 768p75 and 1080i96 resolutions. With stock board installed to green, I did see bit more noise in dark gray raster with both resolutions. I was looking throuh lens to tubes face. Couldn't test without modded input and driver board, because those modded ones are all I have.
Add first that over 1 M ohm (G90 have 10 M ohm) resistor to pin 7 to see if it have any effect. Also pin 7 to ground should be fine, but it's worth to test.
Plain 1209 (non s) is different story, because pin 7 is not connected to anywhere I think.
210V line for neck boards would be noisiest, so I suggest that you mod just it to one neck board to see how much difference it make. If you like to go further, mod one board at time so it's easier to track if problems occur.
Input board R762719 already has series inductors at power lines input, so I just added little capacitance.
+12V line
C612 -> swap to 100uF 25V
+5V line
C604 -> swap to 100uF 25V
-17V line
C606 -> swap to 100uF 25V
-12V line
C608 -> swap to 100uF 25V
-5V line
C624 -> swap to 100uF 25V
Driver board R762720
+17V line
SR101 -> pull other leg up and ad 33uH inductor series with SR101
C134 -> swap to 470uF 35V
+12V line
C133 -> swap to 100uF 25V
+5V line
C137 -> swap to 100uF 25V
-17V line
SR100 -> pull other leg up and ad 33uH inductor series with SR10
C124 -> swap to 470uF 35V
-12V line
C130 -> swap to 100uF 25V
-5V line
C127 -> swap to 100uF 25V
Neck boards R762839 (1209s) or R762721 (808s)
(all components are in amplifier board, except C28 is in socket board)
+210V line
SR4 -> pull other leg up and ad 33uH inductor series with SR4
C25 -> swap to 22uF 250V
+12V line
SR3 -> pull other leg up and ad 33uH inductor series with SR3
C28 -> swap to 100uF 25V (socket board)
-9V line
SR2 -> pull other leg up and ad 33uH inductor series with SR2
C30 -> swap to 470uF 35V
-5V line
C31 -> swap to 100uF 25V
Here is parts I used for modding input-, driver- and 3 neck boards power lines.
https://www1.elfa.se/elfa~se_sv/b2b/catalogstart.do?tab=catalog
33uH inductor
2+3+3+3=11 pcs
ELFA no 58-085-14
100uF 25V el cap
5+4+2+2+2=15 pcs
ELFA no 67-228-70
470uF 35V el cap
2+1+1+1=5 pcs
ELFA no 67-229-79
22uF 250V el cap
1+1+1=3 pcs
ELFA no 67-114-44
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VideoGrabber
Joined: 09 Apr 2006
Posts: 933
Location: Michigan
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| Posted: Thu Nov 05, 2009 3:59 pm Post subject: |
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Ile,
thanks very much for sharing all this! As TbX said, it's great to see what others have done with their PJs. Especially so since many of us have 808-series units, or their derivatives.
_________________
- Tim
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TbX
Joined: 06 May 2006
Posts: 94
Location: Sweden
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| Posted: Thu Nov 05, 2009 7:17 pm Post subject: |
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very grateful incredibly useful compilation
now I will order the parts
did you see any improvement in the bright parts of the image that´s where I see it most
//TbX
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Mark_A_W
Joined: 15 Mar 2006
Posts: 3068
Location: Sunny Melbourne Australia
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| Posted: Fri Nov 06, 2009 1:22 am Post subject: |
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| Tom.W wrote: | | Did you add the resister to pin 7 (KH1) of the LUG's ? |
I'm with you Tom.
The KH grid is not connected properly.
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Fri Nov 06, 2009 1:36 pm Post subject: |
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| TbX wrote: | did you see any improvement in the bright parts of the image that´s where I see it most
//TbX |
It's easier to see difference from tubes face, so I used only dark gray picture. It should have same effect for whites.
How high is your contrast settings?
I use 50 contrast for my small screen.
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TbX
Joined: 06 May 2006
Posts: 94
Location: Sweden
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| Posted: Fri Nov 06, 2009 8:45 pm Post subject: |
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@mark I'll join pin7 to gnd thru 1M or to G1 as greg suggested ?
@ile my screen is 2.8 meters wide so i run my contrast to 67 ( then my blue start to lose focus )
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Mark_A_W
Joined: 15 Mar 2006
Posts: 3068
Location: Sunny Melbourne Australia
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| Posted: Fri Nov 06, 2009 10:34 pm Post subject: |
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Yes, connect the resistor between KH pin and ground.
NEC uses a 3M3 resistor, from memory, on the 8" version of the LUG (P16LJE07).
But 1M should be fine.
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