CurtPalme.com Home Theater Forum

JPM · Joined: 18 Nov 2008 Posts: 17

Hi,

I'm new in this board. My english isn't very well. About 2 weeks ago i bought a Marquee 8500. I have a problem now. I can't center the raster on the tubes. If I try to do this in the mechanical setup, the raster will only move in vertical directions, but not horizontal. I have read something about "the golden rule",which says, that a centered raster is obviously one of the most important settings. My raster is too far at the right side of the tube.
Can anybody help me?

Thank you!
JPM

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

You will need to center it with the focus coil. read down to the section for focus Yoke.

http://www.etechvideo.com/techtip9.htm#13

Athanasios

1031 · Joined: 22 Mar 2006 Posts: 657 Location: Finland

If you mean that at gonvergence menu you cannot move rasters by remote (that firts part of adjustment) Then i would clean all contacts on controll module and also on hdm. Firts you can just reseat those and see if that helps. I installed two weeks back one M8000 projector and that one had same problem, that problem solved just by cleaning all sockedet chips contacks, you shoud use proper cleaning spray, like prf 6-68.

JPM · Joined: 18 Nov 2008 Posts: 17

Thank you for the answers.

@1031: It is the steps 5 up to 8 in the mechanical setup guide, where i have to look into the tubes und move the raster by remote control. I just reseated the HDM 2 or 3 times with no effect. I'll try to clean it and the control module, like you said.

@Nashou66: This looks like a method, that would definitely solve my problem, but i'll better try cleaning the boards first, because i'm not familliar with replacing tubes or lenses.

JPM

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

**Curt Palme** · Posted: Wed Nov 19, 2008 3:58 pm Post subject:

A failure on the HDM will also cause the center square not to move left or right on all tubes.

JPM · Joined: 18 Nov 2008 Posts: 17

Hi,

would this mean, that I need a new hdm board, or would it be enough to center the raster with the focus coil, like Nashou66 said? The cleaning needs some time, my electronics dealer has no cleaning spray fpr high voltage electronic parts, so I have to order it via internet.

JPM

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

You can just pull the chips out and put them back in a few times to clean any oxidation that might be on them for now till you get the cleaner or use Denatured alcohol and clean the chips and the whole board with a soft toothbrush. use the alcohol liberally and then use a compressed can of air to blow out any from in the pins, let dry over night or at least a few hours and then blow some air around chips to see if any is left, I have done he claening and used the board a few hours later.

I would go and do a complete re initialization of the machine now and center the magnetics now while you wait for the cleaner to clean the chips. see if the grids are all level with the horizon and are centered to the tube face, not the screen. if they are not centered on the tube face use the magnetics first. then after you can fine tune with the electronics, however i must say this is only good if you know for sure there is nothing wrong with the electronic centering. Because the electronics may be shifting the raster over now with a fault present , so after you center via the mags and then the electronics are fixed and you zero out all settings you may need to revisit the mags again, i think i just went against what i told you you should do ! Shocked

Some times I confuse myself !

But i think you should now wait till you know for sure its not the CLM or the HDM as Curt stated, but you should definitely check the mags after you know everything is ok electronic wise. The less you need electronic adjustment the better off in the long run.

Athanasios

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

JPM · Joined: 18 Nov 2008 Posts: 17

Hi,
I reseated the HDM and the CLM for a few times. How can I find out, if there is a failure on the HDM? No effects. I think cleaning wouldn't help, if there is a failure, isn't it?

@draganm: Which leads do you talk about exactly? The same you have to switch for scan reversal?

Thank you.
JPM

**Curt Palme** · Posted: Thu Nov 20, 2008 2:56 pm Post subject:

You need to do board swaps at this point, or send me some of the boards to test for you in a working set.

JPM · Joined: 18 Nov 2008 Posts: 17

So,
I've tried to center the raster with the fucos coil, it moved a little bit, but its still not in the middle of the tube. Now I believe, it is really a failure on the HDM or dirt on the boards/chips. I won't be able to fix the problem by magnetics alignment.

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

JPM · Joined: 18 Nov 2008 Posts: 17

Hm, maybe i should try the alignment again. I found a new dealer, where i can buy the cleaner tomorrow.

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

JPM · Joined: 18 Nov 2008 Posts: 17

Hi Nashou66,

can you tell me, how I can get the U7 chip out of its socket?

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

you will ned an IC puller like this, Computer stores have them or radio Shack.

Nashou

JPM · Joined: 18 Nov 2008 Posts: 17

Hi,
while cleaning the CLB I saw that a german called ELKO looks like being not ok. I made a picture of it. It is directly beside the U7 chip. Could this be the reason of my problem?

Thanks.
JPM

Joust · Posted: Fri Nov 28, 2008 1:35 pm Post subject:

That cap has leaked out its magic alright. good place to start in replacing the caps on that board.
If one board is starting to exhibit bad caps, chances are others are too.

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

Those are buffering caps for some amps on the DPB, I would think they may have something to do with it yes. Need too look at the Schematics more it may also be for U7. Its the only electrolytics on that board or the CLM. The SWB next to the DPB has some also. As these sets age changing all caps is just a good idea but can get expensive for the whole PJ.

Athanasios