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jaredjaric
Joined: 05 Jun 2007
Posts: 228
Location: Philippines
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| Posted: Fri Oct 31, 2008 3:16 am Post subject: bright scenes causes barco 808 to mute video. |
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have a new problem with my pj.The 808 non s can not project a bright white scene with out the video muting.It seems like some video ic is clipping.Or some board sees the contrast as too hot.
No red leds and scan fail indications,eht is working(no red leds) when the video is muted.restarting it fixes the problem,but when it reaches a scene with bright scenes the video mutes,even adjustment menu does not show up.
I first suspected the moome box ext hd causing this,so i turned down the gamma,which helped a little but still conks out on bright scenes.
Tubes are still great with a hint of big 4:3 raster.probably an 8 on blue and green crts.And 3900 hrs run in time.
Can gamma boosts accelerated wear on some parts?
Blue tubes are still bright and sharp,no g2 grids come up when g2 adjusted to the max,For me this indicates the blue tubes still with a lot of life.
My kid plays a lot of Ps3 games with this unit, have readjusted g2 and 17volts three times since then.
What could have cause this?Please help 
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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 Oct 31, 2008 4:11 am Post subject: |
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THat is a new one on me. Usually I would suspect HV failure (with the red LED on), but if it's off... ???
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ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
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| Posted: Fri Oct 31, 2008 4:29 am Post subject: |
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Maybe it's an instability in the HVPS?!?! I know less than 1% of what Curt knows, but could high contrast be pulling something down in in the LVPS that needs a reset to correct?
What happens if you turn contrast down? Does it still happen?
SC
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Mark_A_W
Joined: 15 Mar 2006
Posts: 3068
Location: Sunny Melbourne Australia
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| Posted: Fri Oct 31, 2008 4:37 am Post subject: |
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I don't know Barcos, but that sounds like a High Voltage protection circuit kicking in.
Either because the protection circuit needs adjustment, or because the HV is actually running too high.
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zGman
Joined: 22 May 2006
Posts: 599
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| Posted: Fri Oct 31, 2008 4:53 am Post subject: |
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Double check that the video level on the moome ext is turned all the way down,
Barco does not need video boost, possibly overdriving inputs...
You could try another source, perhaps a PC...
G
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jaredjaric
Joined: 05 Jun 2007
Posts: 228
Location: Philippines
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| Posted: Fri Oct 31, 2008 9:12 am Post subject: |
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| ecrabb wrote: | Maybe it's an instability in the HVPS?!?! I know less than 1% of what Curt knows, but could high contrast be pulling something down in in the LVPS that needs a reset to correct?
What happens if you turn contrast down? Does it still happen?
SC |
Turning the contrast way down ,the video eventually shuts off after 20 minutes,and normalize after restart.And the pj mutes again after a while.Turning the contrast way up causes the video shut down right away.
Have tried this process without the moome box,just the adjustment menu was projected.
have also been using smps from a barco 808 S.(sony tube) and swapped it out with the original Smps.
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jaredjaric
Joined: 05 Jun 2007
Posts: 228
Location: Philippines
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| Posted: Sat Nov 01, 2008 8:32 am Post subject: moome box |
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| zGman wrote: | Double check that the video level on the moome ext is turned all the way down,
Barco does not need video boost, possibly overdriving inputs...
You could try another source, perhaps a PC...
G |
Yes,have turned down the gamma boost inside the unit,still problem persists.Thanks guys for the input.
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jaredjaric
Joined: 05 Jun 2007
Posts: 228
Location: Philippines
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| Posted: Sat Nov 01, 2008 8:37 am Post subject: HV adjustment |
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| Mark_A_W wrote: | I don't know Barcos, but that sounds like a High Voltage protection circuit kicking in.
Either because the protection circuit needs adjustment, or because the HV is actually running too high. |
HI,where would the hv adjustment be?
( Checked both the g2 and 17volts already. )
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jaredjaric
Joined: 05 Jun 2007
Posts: 228
Location: Philippines
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| Posted: Sat Nov 01, 2008 8:49 am Post subject: Vph06 failing? |
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| Curt Palme wrote: | | THat is a new one on me. Usually I would suspect HV failure (with the red LED on), but if it's off... ??? |
Hi Curt,really need your advice.
Can the vph06 be failing,would a failing mosfet behave like this?
With the moome box turned down.Turning the contrast up to 60percent makes the texts bloom already,and 70 per cent shuts the video down(no scan fail).Thanks.
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jaredjaric
Joined: 05 Jun 2007
Posts: 228
Location: Philippines
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| Posted: Mon Nov 03, 2008 5:42 am Post subject: |
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just to inform that my problem seems fixed,i have replaced the quadrupler last night and all seems normal now.
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