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charlez
Joined: 16 Nov 2006
Posts: 78
Location: Belgium
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| Posted: Fri May 22, 2009 6:42 pm Post subject: pulsating brightness on bd808s |
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hi,
I'm noticing that on all 3 tubes the brightness is pulsing. Most visible on dark scenes.
When projecting a internal pattern the problem is not there.
Using ps3 with hdfury2 on port 5.
What can cause this ?
thx
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secstate
Joined: 20 Mar 2006
Posts: 720
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| Posted: Sat May 23, 2009 12:59 am Post subject: |
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Are you sure it is not there on internal patterns or just that they don't provide the right circumstance for it to show itself? I have seen brightness flashing caused by an SMPS before. Also is it on one or all three colors? Does this have the standard, from the factory neckboards or the higher bandwidth 120 MHz ones? I put the 120 MHz in my Barco Data and it cause a "candle flicker effect" that I never did get to the bottom of. I have seen a 1208s/2 with the same problem. The candle flicker effect was obvious in low brightness scenes and you could make it more obvious by raising the brightness of the raster.
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charlez
Joined: 16 Nov 2006
Posts: 78
Location: Belgium
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| Posted: Sat May 23, 2009 8:31 am Post subject: |
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It is on all 3 tubes.
I checked again and it's there also on internal patterns but it doesn't show very good.
I have the 120mhz neckboards instead of the 75mhz.
Did changing the smps solve the problem in your case ?
I've got some spare.
greetings
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charlez
Joined: 16 Nov 2006
Posts: 78
Location: Belgium
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| Posted: Sat May 23, 2009 8:50 am Post subject: |
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other SMPS same problem
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Sat May 23, 2009 9:51 am Post subject: |
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Could be something ABL related. Are ABL leds off when this happen?
Too bad it can't be turned off from these 120MHz amps. Not sure what happen if you turn ABL pulse off from vertical deflection board switch.
Have you checked 200V line voltage at MP8?
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charlez
Joined: 16 Nov 2006
Posts: 78
Location: Belgium
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| Posted: Sat May 23, 2009 10:35 am Post subject: |
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You mean the G2 led's ?
They are all off.
When i disable abl on vertical def board , the problem is gone.
Other vertical deflection board has the same problem
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secstate
Joined: 20 Mar 2006
Posts: 720
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| Posted: Sat May 23, 2009 1:26 pm Post subject: |
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| charlez wrote: | It is on all 3 tubes.
I checked again and it's there also on internal patterns but it doesn't show very good.
I have the 120mhz neckboards instead of the 75mhz.
Did changing the smps solve the problem in your case ?
I've got some spare.
greetings |
No the SMPS did NOT solve the problem in my 808s (it did in my 1209s). I never did get to the bottom of it. I swapped EHT, Quadrupler, SMPS and several other boards and could never fix it. I sort of suspected it might be the HV splitter but never tried that. I gave up and went back to the stock 75 MHz boards which did NOT have the issue. I found several references to this candle flicker effect and one reference to a tech fixing it but no solutions. My Barco 1209s does not show this problem. It had a different flickering problem that a replacement SMPS solved.
Edit: Please note that I don't think this had to do with using 120Mhz boards in an 808s Data because I also had a 1208s/2 with completely different parts (not one part in common with my 808s) and it had the same problem. Interesting that it might be ABL related, that never occurred to me.
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Sat May 23, 2009 6:36 pm Post subject: |
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| charlez wrote: | When i disable abl on vertical def board , the problem is gone.
Other vertical deflection board has the same problem |
I believe problem is not in vertical deflection board, but it's only place you can sort of disable ABL. It's still active but it wont operate like it should be without ABL pulses applied during vertical flyback.
Can you swap switcher board? It's also involved with ABL.
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charlez
Joined: 16 Nov 2006
Posts: 78
Location: Belgium
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| Posted: Sat May 23, 2009 7:21 pm Post subject: |
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yes, i've got a spare switcher board.
Switched with an other board and problem is still there.
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Sun May 24, 2009 10:01 am Post subject: |
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Too hot signal or something wrong with sync might also cause brightness pulsing.
Have you tested with other source, so that fury2 is not in chain?
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charlez
Joined: 16 Nov 2006
Posts: 78
Location: Belgium
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| Posted: Sun May 24, 2009 12:04 pm Post subject: |
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connected my laptop using vga => 5xbnc and the problem still there.
Is it possible it has something to do with combination of the tubes and the neckboards ?
I'm using P16 tubes and 120mhz neckboard.
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secstate
Joined: 20 Mar 2006
Posts: 720
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| Posted: Sun May 24, 2009 4:39 pm Post subject: |
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| charlez wrote: | connected my laptop using vga => 5xbnc and the problem still there.
Is it possible it has something to do with combination of the tubes and the neckboards ?
I'm using P16 tubes and 120mhz neckboard. |
I tried many sources and if you raise the brightness you can see the flickering in the raster even with no signal present, at least on my 1208s/2 and 808s Data (when the 120 MHz boards were installed). It could also be some relationship to the P16s as I had those as well in my Data 808s. The 1208s/2 had PT22s which are also the higher resolution guns like that p16s. But my current 1209s (Runco 1100) as P19LPBs and they are the same gun as P16/PT22s and it does not have this problem. I spent days swapping boards in my Data 808s and never got to the bottom of it. Finally I gave up and went back to the 75Mhz boards. I posted in several forums and got very little response (most focused on the HV section which I had swapped out other than the splitter). It was a very annoying problem. On the other hand other than streaking (which was more or less not present on my Data 808s once I put the P16s in it, there was really have little difference in the performance of the to neck boards and it was all but invisible at my seating distance). However if you have the streaking then you have a bigger problem.
Out of curiosity what is the build date of your Barco? Both of mine were mid-1997 builds. I have a theory that there was an issue in the earlier S models that was fixed later but I have never seen anything to back that up, it is just a hunch.
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charlez
Joined: 16 Nov 2006
Posts: 78
Location: Belgium
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| Posted: Sun May 24, 2009 6:33 pm Post subject: |
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I replaced the 75mhz neckboard because of the streaking problem.
My barco is from july 1997, but most of the card's are from a more recent model from november 1997.
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Sun May 24, 2009 7:28 pm Post subject: |
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If disabling ABL resolves problem, why don't you use projector without it?
Forgot those leds and adjuste G2 by eye. Project video black from test disc and set color balance to 6500K, brightness to 50 and contrast to zero. Then adjust G2 pots so that you just can see rasters lit up when watching to tubes.
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charlez
Joined: 16 Nov 2006
Posts: 78
Location: Belgium
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| Posted: Sun May 24, 2009 7:33 pm Post subject: |
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does disabling abl have other disadvantages except the 'more easy way' to set G2 correct ?
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Sun May 24, 2009 10:27 pm Post subject: |
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It's supposed to keep grayscale settings constant when tubes worn, but didn't found any problems after I removed it from my 801s.
500/800 don't have ABL and still those keep grayscale settings pretty good.
It seem to cause more trouble than good in Barcos.
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charlez
Joined: 16 Nov 2006
Posts: 78
Location: Belgium
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| Posted: Thu May 28, 2009 7:20 pm Post subject: |
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ok, thx
Disabled abl.
Much better now.
Need to redo grayscale now
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Decibel
Joined: 31 May 2007
Posts: 904
Location: Roma - Italia
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| Posted: Sun Oct 11, 2009 7:38 pm Post subject: |
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| Ile wrote: | | If disabling ABL resolves problem, why don't you use projector without it? |
How to disable ABL circuit in 808s?
_________________
Domenico (Barco fan!)
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Wed Oct 14, 2009 5:13 pm Post subject: |
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| Decibel wrote: | | Ile wrote: | | If disabling ABL resolves problem, why don't you use projector without it? |
How to disable ABL circuit in 808s? |
In G there is switch in vertical board.
D have same switch, but there is also jumpers in neck boards.
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Decibel
Joined: 31 May 2007
Posts: 904
Location: Roma - Italia
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