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CRT_Ben
Joined: 28 Aug 2006
Posts: 1684
Location: Northern Virginia
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| Posted: Sun Oct 07, 2012 4:04 am Post subject: Marquee HV dropping out with no arcing |
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Recently, the high voltage on my 9500 has been dropping out and coming back on within 3-5 seconds - I've seen this before on various chassis, but it was always preceded by a large HV arc, which I assumed caused the temporary HV shutdown.
There is no arcing going on right now, though - sure, there are little static snaps here and there while the projector is running, but those are more or less constant and as far as I can tell there is no pattern to the HV dropouts. Just tonight, I was playing xbox on the projector, and I had a HV dropout after perhaps 30 minutes of operation and then it was fine for another hour. That seems to rule out a heat-related problem. Once in the past, it happened a few times in a row - 2-3 times within a minute, say. Really it just seems kind of random.
Here's what I've swapped with spares with no change in behavior (or rather, no elimination of the dropouts - it's impossible right now to determine frequency of the dropouts and if one part is slightly worse than another):
-HVPS
-LVPS
-HDM
-VIM
I believe other boards that can cause HV shutdown are VNB and vertical deflection, but I haven't gotten around to switching those out yet.
I was under the impression, though, that if a board caused HV shutdown the set would turn off with HV fail, rather than turning the HV back on immediately. Can the Marquee gurus shed light on the behavior of the set if a board triggers the protection circuits to kill HV?
Thanks in advance,
Ben
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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CRT_Ben
Joined: 28 Aug 2006
Posts: 1684
Location: Northern Virginia
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| Posted: Sun Oct 07, 2012 4:36 am Post subject: |
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| Nashou66 wrote: | do you get the defocus then re focus effect?
Nashou |
Yes. The screen goes totally black for 2-3 seconds, then it lights again and comes back into focus over the next 1-2 seconds. I also hear the crackle of the HV coming back on like when you first turn on the set, and when it first comes back in, it's defocused beyond all recognition. I've seen the same sequence before, but for example once in the past it was caused by a tube arcing internally at the gun. This time around, there's no such trigger I can see.
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barclay66
Joined: 27 Jun 2011
Posts: 1304
Location: Germany
TV/Projector: Marquee 9500 Ultra
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| Posted: Sun Oct 07, 2012 8:26 am Post subject: |
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Hi,
Do You have a spare HV splitter? I'd try to swap this first. Next thing You could do would be connecting only one tube's HV lead and trying one tube after the other. If HV only shuts down with one specific tube I would check it's HV cabling, its neck board and grounding cabling. If HV shutdown would still happen during all testing I would inspect the HVPS connector inside the chassis...
Regards,
barclay66
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dturco
Joined: 06 Feb 2009
Posts: 3778
Location: Eastern Shore Maryland
TV/Projector: Runco DLP VX-3000i Marquee 9500 parts doner
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| Posted: Sun Oct 07, 2012 1:24 pm Post subject: |
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It could also be the vertical board on the rear heatsink. there is a circuit on it that communicates with the HDM.
_________________
Firefly rules. Can't stop the signal.
http://www.hulu.com/firefly
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Sun Oct 07, 2012 3:16 pm Post subject: |
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Hello
A tube can arc inside and give these symptoms with no sound; try running with each anode wire disconnected, one at a time. Let the HV splitter hang down away from the chassis if on a ceiling; or pad under it with three inches of bubble wrap on the floor.
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CRT_Ben
Joined: 28 Aug 2006
Posts: 1684
Location: Northern Virginia
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| Posted: Sun Oct 07, 2012 5:06 pm Post subject: |
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Thank you for your suggestions. I'm going to swap out the splitter prior to watching some football today and see what happens.
Troubleshooting by running one tube at a time will be painful, if it comes to that - as mentioned, it can run for hours without this happening. I certainly wouldn't want to watch anything in monochrome R/G/B for hours at a time, but as it happens my piano is in the same room as the projector. I could practice for a few hours and the projector would probably get my attention if it flicked off and back on.
Question - could this be caused by a bad deflection coil? I know the coils can be damaged if an arc strikes them, and maybe that happened without my knowing, leading to this problem.
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Sun Oct 07, 2012 5:12 pm Post subject: |
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Hello
I doubt that a deflection coil can go intermittent like that, my instinct is a problem in one of the tubes. Disconnect One Tube at a time for testing.
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friedwart
Joined: 07 Jul 2010
Posts: 54
Location: Earth, Europe, Germany @ N 51°43'10.73'' E 14°39'05.52''
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| Posted: Sun Oct 07, 2012 9:01 pm Post subject: Re: Marquee HV dropping out with no arcing |
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| CRT_Ben wrote: | Recently, the high voltage on my 9500 has been dropping out and coming back on within 3-5 seconds - I've seen this before on various chassis, but it was always preceded by a large HV arc, which I assumed caused the temporary HV shutdown.
Ben |
Hi,
I had the same problem a while ago. Problem was a bad connection from the upper Mobo to the backplane. Reseating solved this.
cheers
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CRT_Ben
Joined: 28 Aug 2006
Posts: 1684
Location: Northern Virginia
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| Posted: Sun Oct 07, 2012 9:12 pm Post subject: |
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Swapped the following with no change:
-Splitter
-Green VNB
-Vertical Deflection
I'm now watching the Patriots in monochrome blue, it's screwing with my eyes something awful.
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CRT_Ben
Joined: 28 Aug 2006
Posts: 1684
Location: Northern Virginia
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| Posted: Sun Oct 07, 2012 9:15 pm Post subject: Re: Marquee HV dropping out with no arcing |
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| friedwart wrote: | | CRT_Ben wrote: | Recently, the high voltage on my 9500 has been dropping out and coming back on within 3-5 seconds - I've seen this before on various chassis, but it was always preceded by a large HV arc, which I assumed caused the temporary HV shutdown.
Ben |
Hi,
I had the same problem a while ago. Problem was a bad connection from the upper Mobo to the backplane. Reseating solved this.
cheers |
Thanks for the information! How much of the projector do you have to take apart to reseat this connection? If it requires dropping the tubes from the projector, maybe I could put some stabilant in / on the connection in hopes it would wick into the connector.
Thanks!
Ben
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friedwart
Joined: 07 Jul 2010
Posts: 54
Location: Earth, Europe, Germany @ N 51°43'10.73'' E 14°39'05.52''
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| Posted: Sun Oct 07, 2012 9:32 pm Post subject: Re: Marquee HV dropping out with no arcing |
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| CRT_Ben wrote: |
Thanks for the information! How much of the projector do you have to take apart to reseat this connection? If it requires dropping the tubes from the projector, maybe I could put some stabilant in / on the connection in hopes it would wick into the connector.
Thanks!
Ben |
Oh yeah, I had to remove the tubes. I did it as a complete package and put them back as a package. There was no need for a mechanical adjustment.
I took that opportunity to upgrade my standard 8500 to an ultra one by swapping the upper mobo and the focus board.
cheers
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Sun Oct 07, 2012 9:49 pm Post subject: |
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| CRT_Ben wrote: |
I'm now watching the Patriots in monochrome blue, it's screwing with my eyes something awful. |
Pretend it's a night game...........
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CRT_Ben
Joined: 28 Aug 2006
Posts: 1684
Location: Northern Virginia
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| Posted: Sun Oct 07, 2012 10:07 pm Post subject: |
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| Tim in Phoenix wrote: | | CRT_Ben wrote: |
I'm now watching the Patriots in monochrome blue, it's screwing with my eyes something awful. |
Pretend it's a night game...........
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Bah! After an hour of no problems, I'm now watching in green monochrome. At least I can see the grass now
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Sun Oct 07, 2012 10:46 pm Post subject: |
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Hello
Do you have high humidity there?
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CRT_Ben
Joined: 28 Aug 2006
Posts: 1684
Location: Northern Virginia
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| Posted: Sun Oct 07, 2012 10:55 pm Post subject: |
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| Tim in Phoenix wrote: | Hello
Do you have high humidity there?
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Well, right now, yes. It's raining
This has been going on for about a week and a half, though, and it hasn't been wet the entire time. Granted, I can't recall the weather on the days I used the projector over the past 1.5 weeks, so perhaps I was "unlucky" and used it on humid days.
What are you thinking - high humidity leads to more arcing? That would be external to a tube, though, as the tubes are of course sealed.
Green is good so far, so I'm on to Red in about 10 minutes or so. Not looking forward to it.
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CRT_Ben
Joined: 28 Aug 2006
Posts: 1684
Location: Northern Virginia
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| Posted: Sun Oct 07, 2012 10:59 pm Post subject: Re: Marquee HV dropping out with no arcing |
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| friedwart wrote: | | CRT_Ben wrote: |
Thanks for the information! How much of the projector do you have to take apart to reseat this connection? If it requires dropping the tubes from the projector, maybe I could put some stabilant in / on the connection in hopes it would wick into the connector.
Thanks!
Ben |
Oh yeah, I had to remove the tubes. I did it as a complete package and put them back as a package. There was no need for a mechanical adjustment.
I took that opportunity to upgrade my standard 8500 to an ultra one by swapping the upper mobo and the focus board.
cheers |
Thank you - it never occurred to me that you could remove the tubes as a package. I suppose it makes sense, though.
I wonder if I can remove the HDM and focus boards and simply wiggle the mobo a bit, and apply some stabilant...anything to avoid taking out the tubes!
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CRT_Ben
Joined: 28 Aug 2006
Posts: 1684
Location: Northern Virginia
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| Posted: Sun Oct 07, 2012 11:34 pm Post subject: |
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I'm in night-mode
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friedwart
Joined: 07 Jul 2010
Posts: 54
Location: Earth, Europe, Germany @ N 51°43'10.73'' E 14°39'05.52''
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| Posted: Mon Oct 08, 2012 12:33 am Post subject: Re: Marquee HV dropping out with no arcing |
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| CRT_Ben wrote: |
I wonder if I can remove the HDM and focus boards and simply wiggle the mobo a bit, and apply some stabilant...anything to avoid taking out the tubes! |
I hesitated too because of the time the disassembling needs. So try it but I doubt wiggling the boards will be enough, everything in a Marquee is well fastened.
So long
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CRT_Ben
Joined: 28 Aug 2006
Posts: 1684
Location: Northern Virginia
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| Posted: Mon Oct 08, 2012 1:04 am Post subject: |
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Gave each tube at least an hour and no issues. Running all three tubes again for SNF and no problems in the first 30-45 minutes...maybe it's fixed, but I don't trust it. I hate intermittent problems!
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