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Perry
Joined: 04 Mar 2011
Posts: 25
Location: London, Ontario
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| Posted: Fri Mar 04, 2011 2:38 am Post subject: Marquee 8500 Red Convergence Issue |
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Greetings all!
I have recently become the owner of an 8500! The system works quite well, except for the red tube's convergence. When I enter the convergence setup, (random, interpolated, and guided) I am able to shift the red raster vertically, but not horizontally. The blue shifts both horizontally and vertically and is fully converged. What's even weirder is that the only section that I am able to move the red horizontally is in the center, but not anywhere else.
I believe it is either the convergence board or the main controller board. Most likely it is not the controller board though, as it is taking commands properly from both the remote and RS232.
Anybody else had this issue? What can be done? Help!?
Thanks!
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Fri Mar 04, 2011 2:59 am Post subject: |
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Hello
You likely have an issue with the red H convergence amp. Other distant possibilities are problems in the red convergence yoke, top mother board, the ribbon cable connecting the amp to the mother board, or control board issues. I would try a convergence amp first, Curt has them.
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Fri Mar 04, 2011 3:51 am Post subject: |
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Perry first off id clean all removable chips on the CLM. get some Caig cleaner and protectant from Radio shack along with an IC puller.
Do one chip at a time and its associated socket. remove the smaller daughter boards and get those contacts as well .
Also remove the small daughter board on the HDM and clean those contacts and chips.
Also recheck all connectors from the CVA and HDM and clean them as well with Caig along with the main Connectors to the Mother boards.
If this was an unit you just got and it was sitting for a long time this routine cleaning might solve a bunch of issues.
report back
Athanasios
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Perry
Joined: 04 Mar 2011
Posts: 25
Location: London, Ontario
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| Posted: Fri Mar 04, 2011 3:51 pm Post subject: |
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Thank you Tim and Athanasios!
I will try cleaning the modules as described. I use MG Chemicals contact cleaner as opposed to Caig - it works just as well.
If I suspect there are some electrolytic capacitors that have gone (i.e. bulges or leaks), I will desolder and measure them. Thankfully I have lots of capacitors so if that is the case I should be able to replace them.
Perry.
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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 Mar 04, 2011 4:26 pm Post subject: |
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If none of those suggestions work, I can repair the board for you. I suspect component failure rather than capacitor drift.
I'll also argue the point that MG Chemical stuff works as well as Caig.... not hardly!. 
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Perry
Joined: 04 Mar 2011
Posts: 25
Location: London, Ontario
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| Posted: Sat Mar 05, 2011 12:23 am Post subject: |
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So, I did clean and re-seat all the connections. There was no oxidization or gumminess on any of the connections - very clean. The problem is still there! I would also like to add that the projector converged for the first day, then lost the convergence the next and since then is not able to do horizontal shifting of the red tube.
If I am to send boards to you Curt, should I send both the CLM and the CVA? How much would a repair/swap for old module typically cost?
I have asked the seller of the machine if he has any extra boards as he owns a lot of spare parts - we'll see where that goes for the moment.
Thanks again guys. CRT FTW.
Last edited by Perry on Sat Mar 05, 2011 4:36 pm; edited 1 time in total
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draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
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| Posted: Sat Mar 05, 2011 4:16 pm Post subject: |
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It's not uncommon for Red and/or blue CVA channels to fail and with Blue it's usually vertical. I've never seen a bad green one probably because it doesn't have to stretch the raster like the other 2 colors which are shooting at an angle.
They're a real hoot to fix, hats off to Curt.
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Perry
Joined: 04 Mar 2011
Posts: 25
Location: London, Ontario
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| Posted: Sat Mar 05, 2011 8:07 pm Post subject: |
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Ok, so I got a new C, V, and A board and it works!! Yay! Thankfully, I did not have to pay for anything and the guy I bought it from was kind enough to give me one of his spare boards.
Now, to enjoy some films without the dreaded grey halo of my single-chip DLP projector 
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Perry
Joined: 04 Mar 2011
Posts: 25
Location: London, Ontario
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| Posted: Sat Mar 05, 2011 8:11 pm Post subject: |
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Speaking of which....is it possible to drive the C-board too hard? I would like to prevent this from happening again. For the moment, I have done the best mechanical setup I can do as this is a temporary installation basically to evaluate the machine, but it feels like I really had to stretch the system to get it converged. Is something like that driving the C-board hard?
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Sun Mar 06, 2011 12:23 am Post subject: |
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if you have the lines converged vertically without adjusting and have them converged horizontally on the sides then you will be allright.
(vdc changed the resistors to 2*1ohm in parallel to make it 1/2 ohm) for reliability however, if you have not got that upgrade it may be worthwile.
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Sun Mar 06, 2011 1:19 am Post subject: |
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| Perry wrote: | | Speaking of which....is it possible to drive the C-board too hard? I would like to prevent this from happening again. For the moment, I have done the best mechanical setup I can do as this is a temporary installation basically to evaluate the machine, but it feels like I really had to stretch the system to get it converged. Is something like that driving the C-board hard? |
We advise confirming that all yokes are leveled to the horizon on the tube faces and each other. This can involve some effort if the scan yokes have been hot glued; it is easy to tear up yoke windings and ruin a scan yoke. Convergence yokes must be leveled to the scan yokes so the zones go straight up-down, not angled, all sorts of problems can creep in if not aligned correctly. You want to match red and blue raster heights to green in the service menu. You also want to match raster widths for low-band (below 59.5khz) and also for high-band (above 59.5khz), these are done by nulling zone convergence then using a plastic hex tool to adjust the width coils on the horizontal deflection board.
Go to etechvideo.com and see the Tech Tip for magnetics alignment. Be aware that reaching along an operating CRT is an electrocution hazard at 35,000 volts.
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draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
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| Posted: Sun Mar 06, 2011 3:39 pm Post subject: |
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| Perry wrote: | | Ok, so I got a new C, V, and A board |
it's CVA Convergence amplifier | Perry wrote: | | Speaking of which....is it possible to drive the C-board too hard? I would like to prevent this from happening again. For the moment, I have done the best mechanical setup I can do as this is a temporary installation basically to evaluate the machine, but it feels like I really had to stretch the system to get it converged. Is something like that driving the C-board hard? |
like Tim said, go into convergence, push 0 (zero ) to null ( re-set) convergence then check your vertical and horizontal sizes. looking at only the top/bottom-left/right edges of the grid They should all be the same. Stretching of r + B grids horizontally after that is unavoidable.
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Perry
Joined: 04 Mar 2011
Posts: 25
Location: London, Ontario
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| Posted: Sun Mar 06, 2011 4:58 pm Post subject: |
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| draganm wrote: | | it's CVA Convergence amplifier |
Sorry, I'm still getting used to the jargon for this PJ, but the entire assembly that sits on the heat sink has 3 boards for astigmatism, convergence and vertical sync so that is where I think I was getting confused. Is that referred to as CVA or it just the middle board that is referred to as CVA?
Could the convergence board could be removed from the vertical board as it seems they are only joined by a little bit of PCB?
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Sun Mar 06, 2011 5:24 pm Post subject: |
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| Perry wrote: | | draganm wrote: | | it's CVA Convergence amplifier |
Sorry, I'm still getting used to the jargon for this PJ, but the entire assembly that sits on the heat sink has 3 boards for astigmatism, convergence and vertical sync so that is where I think I was getting confused. Is that referred to as CVA or it just the middle board that is referred to as CVA?
Could the convergence board could be removed from the vertical board as it seems they are only joined by a little bit of PCB? |
The CVA is the middle section and Yes just snap off the vertical board when replacing. Be sure to get the heat sink clips back where they started with no transistors bent over, it is rather awkward.
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Perry
Joined: 04 Mar 2011
Posts: 25
Location: London, Ontario
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| Posted: Sun Mar 06, 2011 5:58 pm Post subject: |
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| Tim in Phoenix wrote: | | it is rather awkward. |
Certainly was  Thankfully, they designed it nicely so the heat sink clip fit right over all those transistors with little overlap. It was just a bit of a pain trying to get it on...
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draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
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| Posted: Sun Mar 06, 2011 10:50 pm Post subject: |
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| Perry wrote: | | the entire assembly that sits on the heat sink has 3 boards for astigmatism, convergence and vertical sync so that is where I think I was getting confused. Is that referred to as CVA or it just the middle board that is referred to as CVA? |
it's 3 separate, VDM (vertical deflection module), CVA and Stig amp.
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