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CZ Eddie
Joined: 23 Mar 2006
Posts: 1601
Location: Austin, TX
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| Posted: Fri Jul 23, 2010 12:45 am Post subject: Marquee 8500 won't power up - EDIT: fixed |
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EDIT: THE ISSUE IS FIXED, THANKS TO TSE & MP!
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Hey guys,
The projector was working fine. Then today I installed a convergence board that arrived in the mail. The set then powered up fine, but I noticed I could not adjust red horizontal convergence. Everything else worked fine.
So I powered off the set & unplugged it. Then put the original convergence board in.
Now the set won't power up at all. I plug it in, see the LVPS fans spinning. Then press the power button and the relays will click a couple times, but instead of getting the HV crackle, nothing else happens. I just get an LVPS fail light on the CLM. And the +24v diagnostic LED on the LVPS starts flashing slowly. This is the 3rd LED from the right, when floor mounted.
This is what I've done so far:
1) Replaced the top half of the LVPS (the side w/out a bunch of caps - I don't have a spare bottom half).
2) Replaced the HDM.
3) Replaced the focus board.
4) Unplugged the HVPS line to one tube at a time.
5) Replaced the HVPS.
6) Reseated the CLM.
7) Reseated the VIM.
9) Replaced the VDM ribbon cable.
There was no change in the problem at any time. The parts I swapped out were known-working parts. Any ideas what to try next?
_________________
Back after a digital sabatical.
Last edited by CZ Eddie on Fri Jul 23, 2010 1:09 am; edited 1 time in total
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tse
Joined: 03 May 2006
Posts: 1014
Location: Sweatbucket, Fl.
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| Posted: Fri Jul 23, 2010 12:55 am Post subject: |
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The Marquee LVPS is a nicely designed unit. It won't turn on with excess current on one of it's outputs. It even tells you which output is overloaded. The +24V LED is telling you that the +24V has the problem. The main rails of the CVA are the + and - 24V. Most likely the problem is there. Double check the spring clips that press the transistors against the heatsink. The ribbon cable is easily misconnected, too. Especially if working without good light.
Scott
_________________
"Were we directed from Washington when to sow and when to reap, we would soon want bread."
Thomas Jefferson
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Fri Jul 23, 2010 12:57 am Post subject: |
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You have somehow shorted that 24 volt rail.
based on what you've done to the set, check the multi-pin connector and make sure the strip that isolates the connectors on the motherboard from touching the heatsink.
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CZ Eddie
Joined: 23 Mar 2006
Posts: 1601
Location: Austin, TX
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| Posted: Fri Jul 23, 2010 1:06 am Post subject: |
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Thanks, TSE! & MP.
I took another look at the ribbon cables and that was it. I never noticed, but they are different. I swapped them around and now the set powers on fine!!
I'll take another look at the red convergence issue after my mini-empanadas jump into my belly. 
edit: convergence issue seems to have also been fixed with the various moving around of parts.
_________________
Back after a digital sabatical.
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JustGreg
Joined: 07 Mar 2006
Posts: 3098
Location: Kenosha, WI
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| Posted: Fri Jul 23, 2010 7:43 am Post subject: |
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Phew...you had me worried that I'd puffed one of the boards without knowing it Eddie. (I'm assuming you installed one or all of the boards I sent to you). BTW...no charge for the MP recommended braided ground strap. 
So Eddie what exactly did you find with the multipin connector? Did you miss a row of pins? Does it matter if the red stripe isn't on Pin 1 like a PC? I quickly looked at the schematics and text overview of those boards and IIRC it states that two pins are jumpered along or in the cable?
A little segue if I may. Nash, MP, Scott, tse, anyone....is there anything to be gained by adding a ferrite ring around the center of the multipin cables? I don't have a scope so can't tell if it made any difference or not. The only danger I could see using them is if they weren't coated or otherwise prevented from shorting the heatsink boards when the heatsink is closed.
Glad it's moving right along for you Eddie.  I have some mounting issues to work out but I'm finally ready to progress with my setup.
_________________
Greg
"Is it ignorance or apathy? Hey, I don't know and I don't care!" --Jimmy Buffett
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CZ Eddie
Joined: 23 Mar 2006
Posts: 1601
Location: Austin, TX
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| Posted: Fri Jul 23, 2010 2:31 pm Post subject: |
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Nope, Greg. I didn't miss any pins. I just missed the fact that the two ribbon/multipin connectors might look the same from 1' away and both fit on both slots. But the two are wired differently. I can't believe I never messed that up in all of the Marquee that I've ever worked on over the years. That, or I used to know they were different and have just completely forgotten about it.
Your awesome gesture of Next-day-air mailing was in vain, unfortunately. USPS by default requires a signature for this type of delivery and naturally, nobody is home during the day. Had to go pick it up during my lunch hour the next day. Gave me a good excuse to get off campus & get some Wendys lunch though!
I guess you got your PJ worked out too? Good!
_________________
Back after a digital sabatical.
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