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DolbySR
Joined: 08 Jun 2011
Posts: 47
Location: Switzerland
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| Posted: Fri Aug 26, 2011 1:01 pm Post subject: BD808s: Retrace lines suddenly visible |
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Hi folks!
I was just watching an episode of Royal Pains as my Barco Data 808s started to produce picture that was just too blue. As if you yanked up the G2 settings of the blue tube too high. This only happened, when the image itself was bright. Powercycled the unit, same again. A minute later, I could see the retrace lines becoming visible, as far as I can remember on all three colours.
I will leave the set unpowered until I have a point where I can start fixing it.
Do you have any suggestions, what happened? LAst week, I had a Harry Potter Marathon, all 7 movies on BluRay in one session and everything was just fine with my PJ. As said, this started from one moment to the next.
Any help is more than appreciated!
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Fri Aug 26, 2011 2:37 pm Post subject: |
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Sounds like either the G2 card, the V board or the blue video amp is bad.
18+ hours of Harry Potter? Too much for me! 
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DolbySR
Joined: 08 Jun 2011
Posts: 47
Location: Switzerland
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| Posted: Fri Aug 26, 2011 3:35 pm Post subject: |
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Is there a way to tell which board or component is shot? I'd like to minimize the on-time from now on on this set to avoid further damage.
Yea, <18h of Potter isn't for everyone, especially if you are going to watch the last movie right afterwards in an open air cinema ^^
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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| Posted: Fri Aug 26, 2011 5:28 pm Post subject: |
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With no input signal do all the tubes fully turn off ?
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HaydnG90
Joined: 22 May 2006
Posts: 1356
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| Posted: Fri Aug 26, 2011 5:37 pm Post subject: |
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| Curt Palme wrote: |
18+ hours of Harry Potter? Too much for me! |
Exactly. I have a hard time making it through one of the movies. Just not my cup of tea.
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DolbySR
Joined: 08 Jun 2011
Posts: 47
Location: Switzerland
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| Posted: Fri Aug 26, 2011 7:44 pm Post subject: |
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When I connect only the sync signals, I get a mostly blueish picture with visible retrace lines.
Uhm okay ... now that's weird. I just wanted to take a look into the tubes from the front when the PJ is on and now everything is back to normal again.
Attached the R, G and B wires - picture is absolutely ok. No problems anymore.
Any explanation? 
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Fri Aug 26, 2011 7:56 pm Post subject: |
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| DolbySR wrote: | When I connect only the sync signals, I get a mostly blueish picture with visible retrace lines.
Uhm okay ... now that's weird. I just wanted to take a look into the tubes from the front when the PJ is on and now everything is back to normal again.
Attached the R, G and B wires - picture is absolutely ok. No problems anymore.
Any explanation? |
Could be the blue tube going bad. Could be a poor connection between the neckboard and the tube pins. You could try removing and installing the blue neckboard around 20 times to clean the connectors to see if that helps. If none of these then it could be a poor solder joint somewhere or even a board connector. Or a G2 pot if it has one. I dont remember for sure.
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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| Posted: Fri Aug 26, 2011 8:25 pm Post subject: |
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Could have just been a contamination G2 short in the Blue CRT gun. Sounds like it cleared itself......
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Fri Aug 26, 2011 8:37 pm Post subject: |
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| Tom.W wrote: | | Could have just been a contamination G2 short in the Blue CRT gun. Sounds like it cleared itself...... |
Yeah, that's where dreams come from, lol. 
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DolbySR
Joined: 08 Jun 2011
Posts: 47
Location: Switzerland
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| Posted: Sat Aug 27, 2011 7:57 am Post subject: |
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Hey guys!
Well yea, after it worked great again for approx 2 hours, it started to make a fizzing and humming noise, the picture and the unused phosphor regions were again getting brighter. As I remember it was primary the blue gun but also the red one that was behaving strange. I immediately shut down the PJ and as I did, I heard a clearly audible zap from somewhere inside. I did not investigate yesterday since I was already in bed and just turned off my equipment, turned over and went to sleep ^^
I'd say it would be better not to turn on the PJ again until further investigations?
_________________
Greetings and have a nice day,
Patrick
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DolbySR
Joined: 08 Jun 2011
Posts: 47
Location: Switzerland
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| Posted: Sat Aug 27, 2011 1:46 pm Post subject: |
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Quick update...
It seems that there is something wrong with the EHT Module. And there was plenty of dust on the back side of the G2 board, linking some things together...
The faulty EHT module always blows its 2A fuse when powering on. I checked some components and both snubber diodes D25 and D17 failed completely. I then replaced them, powered up the PJ, HV working again but the diodes failed again.
Is there anything you might suggest?
EDIT:
Just swapped the complete HV part (EHT Board and Quad) from my old BG800. I was able to quickly see a picture (it looked fine as far as I can tell and as far as a MTV music video looks "ok"), then zap and the EHT board fuse blew again, taking one snubber diode to the grave as well.
I would suggest, there is something wrong in the HV section?
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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| Posted: Sat Aug 27, 2011 6:08 pm Post subject: |
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You could try swapping out the splitter and or the G2 board. Never had this type of failure before but Curt can most likely test the boards for you. 
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km987654
Joined: 25 Jul 2007
Posts: 2874
Location: Australia
TV/Projector: Barco BG809s
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| Posted: Mon Aug 29, 2011 12:30 am Post subject: |
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| DolbySR wrote: | Quick update...
It seems that there is something wrong with the EHT Module. And there was plenty of dust on the back side of the G2 board, linking some things together...
The faulty EHT module always blows its 2A fuse when powering on. I checked some components and both snubber diodes D25 and D17 failed completely. I then replaced them, powered up the PJ, HV working again but the diodes failed again.
Is there anything you might suggest?
EDIT:
Just swapped the complete HV part (EHT Board and Quad) from my old BG800. I was able to quickly see a picture (it looked fine as far as I can tell and as far as a MTV music video looks "ok"), then zap and the EHT board fuse blew again, taking one snubber diode to the grave as well.
I would suggest, there is something wrong in the HV section? |
EHT circuit contains EHT, H and V boards as well as deflection coils. Its likely one or more of those parts has failed probably either the H and/or V boards. You really need spares to check this.
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DolbySR
Joined: 08 Jun 2011
Posts: 47
Location: Switzerland
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| Posted: Fri Oct 21, 2011 7:38 pm Post subject: |
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Hi there folks.
Finally got some time to check on my PJ again.
Swapped the splitter for a BG800 splitter and replaced the shot snubber diodes on the EHT board. Still the same fault. EHT starts up and when the image starts getting brighter, the picture gets way too blue, the unused phosphor areas begin to glow somehow and somewhere, discharges or arcing can be heard. I then shut down the PJ again. Diodes and EHT fuse were still ok.
Because I don't want so send half of my PJ over to Curt to have the parts checked, I'd like to check as much as I can to rule out which part is not faulty at all.
Question is: Is it possible to power up the HV section without load? E.g. leave the HV wires detached from anything, just let them hang down from the ceiling? Safety precautions taken, for sure... This could rule out some basic problems in the HV section.
_________________
Greetings and have a nice day,
Patrick
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