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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Wed May 28, 2008 8:11 pm Post subject: Convergence (or raster) drifting on my BG808 |
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Hi,
I have a problem on my BG808 that I am trying to fix for a few weeks unsuccessfully.
I have my blue and red rasters drifting slowly during around two hours.
First, I thought that it was a convergence problem, then I removed the convergence tray and looked at the crosses (installation menu) and saw that it was still drifting. The problem is that I can only reproduce the problem after having left the pj unplugged for at least 2 days.
My BG808 has an HDFury + HTPC plugged on port 3 (1280x960@50). I tried to eliminate elements where the problem can be found. I used a VGA cable instead of HDFury : the problem still occurs. I used port 2 (s-video with camcorder), the problem does not appear. I used a DVD player instead of the PC (576p): in progress and it looks as it doesn't drift. I have to wait to be sure.
I also have a problem with 1080p and 1080i on port 3: the picture is dark at some places and looks weird. I don't know if this is related to my drifting problem.
Someone has an idea about my problem ?
Is it something to do with the port 3 ?
I need your help  !!!
P.S : I have done my settings (mechanical and electronic) after the 30 minutes warm-up.
P.S : I also noticed that the red raster drifts almost only from left to right (only vertically) and the blue raster drifts in two directions (vertically and horizontally).
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Person99
Joined: 09 Mar 2006
Posts: 4899
Location: Flower Mound, TX
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| Posted: Wed May 28, 2008 8:14 pm Post subject: |
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New caps for you!
_________________
Dave
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Wed May 28, 2008 8:16 pm Post subject: |
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Ok, but on which board ?
If they need 48 hours to be emptied, what kind of caps are they ? Big, small ?
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picree
Joined: 31 Mar 2006
Posts: 351
Location: Johnson City, TN
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| Posted: Thu May 29, 2008 1:40 am Post subject: |
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Make sure the projector is set up mechanically such that most, if not all, of the electronic geometry controls are set as close to neutral as possible. To rule out a poor mechanical setup as the culprit you could reset all geometry settings to neutral, and see if the same drifting problem occurs. If the rasters stops drifting then it's probably something in the electronic setup that is set to the extreme.
Has the astig been set? Look at a dot pattern and run the focus up and down. Do any of the dot drift? If so, astig is off. Do all the magnetics along the neck of the tubes look like they are all aligned? They should be. Has the projector always done this? This site has a CRT primer for 808's that is a good reference. How much drifting? Are the rasters centered on the tubes? They should be.
Rather than changing out capacitors (because its a pita) you could try swapping boards.
_________________
MAIN THEATER: (JVC RS2000; Yamaha UDP-LX500; Yamaha RX-V2400; Lumagen Radiance Pro, Vertex)
SECOND WII-ATER: (BG808; WII; Oppo 971H; Moome external box; BG-DVI transcoder; tse gamma box; Extron)
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Thu May 29, 2008 5:58 am Post subject: |
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Ok thanks for the advices  . But if everything is ok (crosshatches don't drift at all) with the svideo signal (15KHz) that I plugged to port 2, then it should tell that it is electronic problem, right ?
But anyway, I am going to do all the mechanical adjustements again, just to be sure. The astigmatism should be ok because it was ajusted by a professionnal 6 months ago.
| Quote: | | Has the projector always done this? |
No, the problem occurs a few months ago. What is CRT Primer ?
By the way, when adjusting the crosshatches, do you do that with a 15 KHz signal plugged in or with no signal at all ?
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kal
Forum Administrator
Joined: 06 Mar 2006
Posts: 18114
Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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| Posted: Thu May 29, 2008 3:47 pm Post subject: |
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| Corleone88 wrote: | | Ok thanks for the advices . But if everything is ok (crosshatches don't drift at all) with the svideo signal (15KHz) that I plugged to port 2, then it should tell that it is electronic problem, right ? |
Not necessarily. Drift can occur more at higher resolutions as the electronics are working harder.
Replace the large filter caps in the power supply. That'll make the biggest difference if the mech and electronic setup is correct.
Kal
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Thu May 29, 2008 5:33 pm Post subject: |
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What kind of caps do I have to buy ? The exact same ones ?
What about using a hair-dryer to find on which board the problem is ? I read that somewhere but I don't know if this works.
To check if a cap is fine with a measurement device, do I need do unsolder it ?
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kal
Forum Administrator
Joined: 06 Mar 2006
Posts: 18114
Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Thu May 29, 2008 8:09 pm Post subject: |
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You talked about the SMPS (R762506) and the power supply (R76217055). Which one do I have to change concerning the caps ? Thanks
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kal
Forum Administrator
Joined: 06 Mar 2006
Posts: 18114
Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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| Posted: Thu May 29, 2008 8:30 pm Post subject: |
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Sorry - The SMPS. All of the filter caps on the power supply rails. They're the large ones underneath the left hand side:
Not the 3 or 4 caps before the diode (rectifying) bridge in the power supply (R76217055) which are actually the same as the large black on on the right above (which I also never found helped when I replaced it, though if it's completely shot then it might help).
Start with the ones on the left. Careful with your soldering. You don't want to create any shorts or things that may create other problems. Some people around here (ie: me) have been known to hunt for hours to find the problem. 
Kal
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Gerbrand
Joined: 13 May 2008
Posts: 199
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| Posted: Thu May 29, 2008 10:47 pm Post subject: |
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Hello,
I have been struggling with the same problem for weeks (BG808 also). Before attempting to change caps, I would suggest that you really check your mechanically setup very carefully.
In my case the winning solution (thanks Reinier..) turned out to be threefold:
- make sure that the 17 V point on your SMPS is at 17.5 V with the frequency you are using. The manual says something about using a 15kHz frequency, but I just used the actual source frequency.
- turn the jokes to correct for any tilt differences between the rasters
- ensure that the central convergence square is exactly centered wrt the image. So first center the raster on the tubes, then use the H-phase control (or preferably the timings of your source) to center your image wrt your raster.
At the moment the drift is strongly reduced. It is not gone however  . I am still considering changing caps, but it not that urgent anymore.
I am interested to see how you fare,
Gerbrand
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picree
Joined: 31 Mar 2006
Posts: 351
Location: Johnson City, TN
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| Posted: Fri May 30, 2008 1:44 am Post subject: |
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If your caps look like the ones in kals photo I would hold off for a moment. The caps with the metal casings (S&K I believe) were supposed to be the better caps (rather than the usual shrink wrap ones). That may very well be the solution but I would check everything else first. Of course you can always look for caps that have obvious leakage or bulging...that would be a good clue pointing to the culprit!
_________________
MAIN THEATER: (JVC RS2000; Yamaha UDP-LX500; Yamaha RX-V2400; Lumagen Radiance Pro, Vertex)
SECOND WII-ATER: (BG808; WII; Oppo 971H; Moome external box; BG-DVI transcoder; tse gamma box; Extron)
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kal
Forum Administrator
Joined: 06 Mar 2006
Posts: 18114
Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Fri May 30, 2008 9:08 am Post subject: |
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| Quote: | | make sure that the 17 V point on your SMPS is at 17.5 V with the frequency you are using. The manual says something about using a 15kHz frequency, but I just used the actual source frequency. |
Where is the 17V point ? Between which points to I have to measure the voltage ?
| Quote: | | - turn the jokes to correct for any tilt differences between the rasters |
Where are the yokes ?
| Quote: | - ensure that the central convergence square is exactly centered wrt the image. So first center the raster on the tubes, then use the H-phase control (or preferably the timings of your source) to center your image wrt your raster.
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How do I do the H-phase control (or timings of source) ? Is it the screws to shift vertically and horizontally the blue and red rasters on some of the vertical boards ?
Sorry for all these questions, but I need to be sure what I will have to do
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n@t
Joined: 02 Apr 2006
Posts: 63
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| Posted: Fri May 30, 2008 9:31 am Post subject: |
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Hi,
change Caps on the Convergence Board.
Greetings, Bernd
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think positiv
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Gerbrand
Joined: 13 May 2008
Posts: 199
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| Posted: Fri May 30, 2008 1:06 pm Post subject: |
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| Corleone88 wrote: |
Where is the 17V point ? Between which points to I have to measure the voltage ?
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If you look at Kal's picture of the SMPS, you see a connector next to the caps you are supposed to replace (with yellow wires leading to it). One pin on this connector is free. That is the 17 V point. You should measure it relative to mass (=chassis). BE CAREFUL!! Some of the heat sinks on the SMPS are hot (=connected to the mains voltage).
| Quote: | | Where are the yokes ? |
Check this out:
http://www.curtpalme.com/Yoke.shtm
Basically, the horizontal center lines should be perfectly parallel without any convergence adjustments. Also your rasters should be the same size and centered, so you do not have to apply any raster shift for red or blue.
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How do I do the H-phase control (or timings of source) ? Is it the screws to shift vertically and horizontally the blue and red rasters on some of the vertical boards ?
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No, the H-phase control is something you can adjust from the GEOMETRY menu. The source timings you need to adjust from your source if possible (only possible for HTPC or scalers).
Gerbrand
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Fri May 30, 2008 3:58 pm Post subject: |
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| Quote: | | change Caps on the Convergence Board. |
It is not a problem on the convergence board because after I removed it and the problem still occurs.
Gerland,
The yokes are fine. I am using a HTPC (powerstrip), do you know where the source timings are ?
Tonight, I'll check the voltage. Thanks a lot for your help
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Gerbrand
Joined: 13 May 2008
Posts: 199
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| Posted: Fri May 30, 2008 4:01 pm Post subject: |
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| Corleone88 wrote: |
The yokes are fine. I am using a HTPC (powerstrip), do you know where the source timings are ?
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In Powerstrip I think you have arrows with which you can move the image around.
Gerbrand
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Corleone88
Joined: 09 Dec 2006
Posts: 474
Location: France
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| Posted: Sun Jun 01, 2008 8:06 am Post subject: |
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| Quote: | | make sure that the 17 V point on your SMPS is at 17.5 V with the frequency you are using. The manual says something about using a 15kHz frequency, but I just used the actual source frequency. |
I have 17.61V. Is it ok?
I did the all mechanical setup again and the problem is still there.
I noticed also a few other things:
1. I have to wait around 3 hours to get a perfectly stable convergence.
2. The vertical red lines are perfectly aligned with the green ones after the warm-up and do not drift at all. Does it mean anything?
3. The distance between the horizontal red lines and the green lines is short (after the warm-up): it is the thickness of a line (or maybe two). This is in the convergence menu.
4. The distance between the horizontal (and vertical) blue lines and the green lines is bigger (after the warm-up): it is the thickness of 2 or 3 lines
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Gerbrand
Joined: 13 May 2008
Posts: 199
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| Posted: Sun Jun 01, 2008 11:00 am Post subject: |
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| Corleone88 wrote: |
I have 17.61V. Is it ok?
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Should be fine.
| Quote: |
1. I have to wait around 3 hours to get a perfectly stable convergence.
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I had the same symptoms. In my case the convergence kept changing. It never really got stable.
Some more suggestions:
1) You should always converge using a pattern from the source and if that is not possible, use "genlocked pattern"
2) Maybe you could post a picture of the screen with convergence off?
3) What kind of convergence adjustments do you have? Ideally all squares should be in the 30-70 range.
Gerbrand
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