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qran
Joined: 04 Jan 2012
Posts: 3
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| Posted: Wed Jan 04, 2012 6:08 pm Post subject: Problem with Electrohome M8000 projector |
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In our lab we use a M8000 projector for several years now. Everything worked fine most of the time until the following problem started: When the projector is on standby or when it is supposed to project a completely dark image two of the bulbs actually go off, but the third bulb (red) continues emitting some weak light. This is a problem for the parts of experiments which require complete darkness. I remember we had a similar problem several years ago and it was solved by keeping the projector on standby for several days. This solution, however, doesn't seem to work in this case - at least after three days on standby the the light emitted from the red bulb didn't change. Any other suggestions?
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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: Wed Jan 04, 2012 6:13 pm Post subject: |
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Try swapping the neck boards between the R and G tubes:
http://www.curtpalme.com/ElectrohomeMarquee_Layout7.shtm
If hte problem switches to the green, then the neck board is bad. If the problem stays with the red, then you have a G2 setting in the service menu that might be too high, or the red tube is bad. Fortunately, it's the red tube, I have lots of good stock at $100 + shipping.
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Wed Jan 04, 2012 6:17 pm Post subject: |
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First and most important thing with marquee troubleshoot to clean all socketed ic's legs from any oxidation.
2.)Check the G2 sttings under the white balance setup.
Does it matter which input is selected? Contras-brightness settings affect the lowest emission of the red tube?
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projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Wed Jan 04, 2012 7:07 pm Post subject: |
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According to the tech bulettin the P14 problem is applies on the marquees built between '96 and '98 (past the M8000 series), I don't think that is the problem -then all tubes would behave equally
_________________
projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
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qran
Joined: 04 Jan 2012
Posts: 3
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| Posted: Wed Jan 04, 2012 7:17 pm Post subject: |
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Thanks for the suggestions! It will take me a while to do the hardware testing (neck boards swap). I looked for the G2 setting but can't find them - are they labeled 'G2 settings' in an on-screen menu?
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Wed Jan 04, 2012 7:32 pm Post subject: |
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| qran wrote: | | Thanks for the suggestions! It will take me a while to do the hardware testing (neck boards swap). I looked for the G2 setting but can't find them - are they labeled 'G2 settings' in an on-screen menu? |
they are in the service menu. here is a guide for setting grey scale which also shows how to enter the G2 menu
http://www.etechvideo.com/techtip1.htm
It also shows the P14 voltage measurement procedure. I know its a problem with certain Low voltage power supplies but this machine might have
a different one put it due to age. its best to always check P14 voltage no matter which PS version you have, why take a chance?
Another thing you might want to do is initialize the set again, doing so will erase all memories and set up.
if you have a computer you can down load the setting before hand with the Marquee loader program. An RS 232 connection is needed.
here is a direct link that will down load immediately
http://vdcds.com/utilities/Marquee23.zip
The initialization command is also in the service menu. Some times memoir blocks become corrupted and can cause
dimming of tubes or changes in geometry etc. Clearing them all out can sometimes fix the issue. For me it is easier to down load my settings initialize and re load settings and test PJ than swapping boards out.
if you can not see the menu screen due to the tubes not illuminating then you need the loader/control program
to get to the menu's.
Athanasios
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Last edited by Nashou66 on Wed Jan 04, 2012 7:33 pm; edited 1 time in total
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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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: Wed Jan 04, 2012 7:33 pm Post subject: |
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Before you do that, beware that this will wipe clean all the memory locations, and you'll need to do a complete setup of the set again. As long as you can do that, I'd also recommend doing an initialization. Also check the memory battery on the CLM at this point, it should be 3 volts.
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qran
Joined: 04 Jan 2012
Posts: 3
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| Posted: Wed Jan 04, 2012 10:06 pm Post subject: |
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@Nashou I'm in Montreal.
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