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jimdscott
Joined: 19 Oct 2007 Posts: 13
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| Posted: Fri Oct 19, 2007 7:12 pm Post subject: Marquee 8500 Ceiling Mount / Horizontal Reverse Scan |
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I'm thinking about setting up a ceiling mount for my Marquee 8500. According to the user manual, I need reverse scan set up for a front projection ceiling mount. The install manual says that the horizontal and vertical deflection yokes can be reversed for ceiling use.
Is this an easy task? The user manual says it has to be done by service personnel. This pic (http://www.curtpalme.com/ElectrohomeMarquee_Layout3.shtm) shows me where to find the 3 vertical yoke connectors. Those look easy enough to reverse. I'm more concerned about the horizontal yoke connectors. Looking at these instructions: http://www.curtpalme.com/ElectrohomeMarquee_Layout9.shtm makes me nervous.
| Quote: | | Here is an overview of the HDM or horizontal deflection/output module. This board sits vertically between the blue and green CRTs. It contains the circuitry for the horizontal deflection, and controls the center square raster shift in a horizontal direction. The thick group of wires connect to each deflection yoke for each CRT. The white connectors pull apart to flip the image in an H direction. Make sure you only disconnect the yoke wires after the set has been turned off and unplugged for at least a minute to discharge all high voltages in this area. |
What exactly do I have to do with the white wires to reverse the horizontal scan? Thanks for your replies.
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fuzzybee
Joined: 26 Sep 2006 Posts: 187
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| Posted: Fri Oct 19, 2007 7:21 pm Post subject: |
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It just involves unplugging the wires shown here: http://www.curtpalme.com/ElectrohomeMarquee_Layout3.shtm (6 total), turning them around 180 degrees, and plugging them back in. Piece of cake.
Edit - actually, only three of the cables are shown there - the other three are on the horizontal deflection board.
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jimdscott
Joined: 19 Oct 2007 Posts: 13
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| Posted: Fri Oct 19, 2007 7:25 pm Post subject: |
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Thanks, fuzzybee. I see where to reverse the vertical yoke connectors, but are the horizontal yoke connectors on that page? I thought I also had to do something with the white wires on the horizontal output board (http://www.curtpalme.com/ElectrohomeMarquee_Layout9.shtm)?
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JustGreg
Joined: 07 Mar 2006 Posts: 3098 Location: Kenosha, WI
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| Posted: Fri Oct 19, 2007 7:31 pm Post subject: |
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And if I could offer one more thing...be very careful to make sure you get all the pins in the sockets. They aren't designed to prevent coupling if you have a pin outside of the female connector. Get it wrong and you run the risk of releasing the magic smoke.
Greg
_________________ Greg
"Is it ignorance or apathy? Hey, I don't know and I don't care!" --Jimmy Buffett
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jimdscott
Joined: 19 Oct 2007 Posts: 13
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| Posted: Fri Oct 19, 2007 7:39 pm Post subject: |
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Thanks, JustGreg. I'm probably being dim here, but I'm not sure whether I need to reverse the 3 V yoke connectors shown (http://www.curtpalme.com/ElectrohomeMarquee_Layout3.shtm) or whether there are 3 more connectors that I need to reverse as well.
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JustGreg
Joined: 07 Mar 2006 Posts: 3098 Location: Kenosha, WI
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| Posted: Fri Oct 19, 2007 8:15 pm Post subject: |
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Yup...there's three more. Coming out the top rear of each tube housing you'll see some 12 gauge-ish wires terminating in a white connector. They all lead to the HDM board. On each connector there's a label with the words Reverse Scan (or something like that) on them. The connectors are kinda weird in that there isn't just a male with fixed pins and a female side. There's a middle segment with pins too. Anyway, use a Sharpie and before you change anything just run a line across all three parts so if you get lost you can find your way back. It's also a quick reference for changing the scan later.
Again, just make sure no pins are outside a connector. It's easy to do.
Greg
_________________ Greg
"Is it ignorance or apathy? Hey, I don't know and I don't care!" --Jimmy Buffett
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jimdscott
Joined: 19 Oct 2007 Posts: 13
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| Posted: Fri Oct 19, 2007 8:23 pm Post subject: |
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Thanks again. I'll give it a go. Out of curiosity, why does the horizontal scan need to be reversed for a ceiling mount, front projection? That seems counter-intuitive to me. I would think if a front screen, floor mount is "regular/regular" than a rear screen, ceiling mount should be "reverse/reverse". But the rear screen, ceiling mount is "regular/reverse" while the front screen, ceiling mount is "reverse/reverse".
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JustGreg
Joined: 07 Mar 2006 Posts: 3098 Location: Kenosha, WI
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| Posted: Fri Oct 19, 2007 9:07 pm Post subject: |
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Ummmm...ummmm....here's $5.00. Go outside and play.
Curt? Tim? Help?
_________________ Greg
"Is it ignorance or apathy? Hey, I don't know and I don't care!" --Jimmy Buffett
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Tim in Phoenix
Joined: 21 Oct 2006 Posts: 4409 Location: Phoenix
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jimdscott
Joined: 19 Oct 2007 Posts: 13
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| Posted: Mon Oct 22, 2007 12:27 pm Post subject: |
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Thanks, everyone. That was very easy. It was also unnecessary -- I didn't realize that "ceiling mount" meant hanging the unit upside down from the ceiling. My setup is a "tower mount". I built a 5' tower to hold my components, then installed the PJ on top of that. I learned three very important things:
1. Ceiling mount means upside down.
2. Projector points to the middle of the screen, not the top/bottom.
3. If you're careful, you can make a lot of mistakes without screwing anything up too badly.
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26706 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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| Posted: Tue Oct 23, 2007 4:54 am Post subject: |
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| jimdscott wrote: | Thanks, everyone. That was very easy. It was also unnecessary -- I didn't realize that "ceiling mount" meant hanging the unit upside down from the ceiling. My setup is a "tower mount". I built a 5' tower to hold my components, then installed the PJ on top of that. I learned three very important things:
1. Ceiling mount means upside down.
2. Projector points to the middle of the screen, not the top/bottom.
3. If you're careful, you can make a lot of mistakes without screwing anything up too badly. |
I think you just found your newby signature.
What you did was essentially a cart mount:
http://www.curtpalme.com/forum/album_page.php?pic_id=293
_________________ Tech support for nothing
CRT.
HD done right!
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