CurtPalme.com Home Theater Forum

**Curt Palme** · Posted: Wed Dec 09, 2009 12:19 am Post subject: Strange Marquee problem...

Look at these two pix. This is a fault I've seen a few times, this time I am determined to nail it.

A 27K hour Marquee 8500 non Ultra. Good tubes, good emisisons in the mid-high 60s. Minimal wear on the green.

top pix is at 60/60 contrast and brightness. IN real life the gray scale is tinted a bit towards the green. Towards 100 IRE, the color shifts to pink.

At 100 contrast/60 brightness, the pix goes far to pink, esp as you approach 100IRE.

I've seen this before in these sets, and have no idea what's causing it. CCM is set to 50 all around.

I know on one set I had before with this issue, I swapped the CCM, ACON, HV and LV power supplies before I parted it out. I will take this one a step at a time as I want to sell this one. Anyone seen this before?

(ignore the shadow at the bottom of the image, it's a G90 that jumped in front of the camera. Smile

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

Curt i hate to say this yes, these longbows are giving me a head ache, well the one I have has a slight color shifting like yours has. mine gets yellowish towards one part of the screen and pinkish on the other side opposite and diagonally. looks like your first pic but with two different colors yellow and pink but not as bad as that. very faint but i can see it. I thought it might be the gain on me screen. in early january i am getting a new Hurley unity gain screen so i'll know more then.

I have feeling its bad tube phosphor. try different tubes as I am curious.

Athanasios

**Curt Palme** · Posted: Wed Dec 09, 2009 12:32 am Post subject:

I did that on the last set, and that wasn't it.

The problem isn't quite as shown above (stupid point and shoot!).

The problem is a distinct shift to pink (red) as you get closer to 100IRE. It's equal on both ramps of the test pattern, equal in all corners, and decreases in effect as you ramp the contrast down. With contrast at say 40 or so, the gray scale is almost perfect.

Turn on each tube individually, and it's not obvious, each tube looks uniform.

I'm sure I'll figure it out, but it's pissing me off. Smile

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

Did you try the CLM? maybe the drive signals for the red is getting messed up? Scope it while ramping the contrast. maybe that will give you some insight as compared to a set that doesnt do it. scope both sets to compare obviously Wink

Athanasios

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

What happens when you lower contrast? does it shift more to another color? like green? If so then the red drive is over reacting to the adjustment. possibly right? Adjusting contrast should not affect greyscale that much.

Athanasios

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Try another neck board damn it..... Laughing

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

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

If it shifts towards pink as you increase contrast, wouldn't that indicate a restriction in the available HV going to the green tube causing it to not excite the phosphor enough to maintain the proper greyscale ? Pink whites mean a burned green, usually, but if it follows the tubes, then it would indicate the circuitry which generates the beam intensity, no ?

I'm not tech, OBVIOUSLY, but wouldn't logic dictate where to look as the beam intensity circuitry ? If you swap all wires from green to blue tube can you make it go yellow when you turn up the contrast ?

**Curt Palme** · Posted: Wed Dec 09, 2009 1:44 am Post subject:

I swear I tried everything on the other 8500. So far I've swapped the VIM and CLM from a set that runs perfectly, and I've disconnected the V board/stig connector. Still the same problem. Pulled the CMM as well. I'll try some more tomorrow.

It appears to be a gain issue more than a G2 level/HV drifting, as the lower IRE appear fine. Even in the above pix, you can still see that slight greenish tint from about 0-30 IRE.

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

VIM or neck-board followed possibly by CLM. Probably the VIM as it's maintaining the color tracking of each tube as output increases. This reminds of poor blue gamma tracking like the old 8000's had except it's much worse and it's on Red.
I can't see it being a problem with the HV or the splitter unless the HV wire from HVPS is in the wrong port. Even then I think this is unlikely.
One thing i've noticed in the last couple of years is bad VIM's and CLM's, something you never saw lets say 3 years ago. I've managed to re-hab a couple by repalcing the little yellow Tant's at the input sections. If the problem is any deeper than that I throw it in a parts box Surprised

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

What happens when you lower the Contrast to about 40 curt? do the darker IRE's become Green?

Athanasios

**Curt Palme** · Posted: Wed Dec 09, 2009 1:48 am Post subject:

A bit, but everything falls into range really. In the first pix, the whole color temp is a mile off, but it's consistent from say a contrast of 10 to a contrast of 40-45. Anything above that, and the bright areas really start shifting into pink.

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

did you try swaping the focus connector from red to say blue? i wonder if the focus is blooming in the red earlier and causing the pinkish tint.

Athansios

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

I still havn't seen where you say you tried neckboards. Yes, No?

**Curt Palme** · Posted: Wed Dec 09, 2009 2:34 am Post subject:

I did on the last set for sure. Not with this one. I will tomorrow.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

If neckboard doesn't fix it I'll give you something to try if you want.

At your lower contrast, bring up an internal dot pattern and separate the 3 colors both vert and Horz so you have all 3 colors of dots. Defocus them and make sure they are all round and centered. Now leave them separated and defocused and raise up your contrast and make sure they stay round and center all the way up in contrast. If they are ok then lower your contrast back down and now focus all 3 colors including blue. Leave them separated are run your contrast up again and make sure they stay focused all the way up. I'm sure you know what I'm getting at. Very Happy

antorsae · Joined: 16 Jul 2006 Posts: 297

Curt - maybe on tube is saturating before the others. If you set G2/DRIVE too high and then you crank contrast up too much may may high saturation. This would happen on a tube first. If pic turns pink, it's green that is saturating before red/blue. At some point light output gets saturated and one tube will start doing it before the others...

**Curt Palme** · Posted: Wed Dec 09, 2009 3:07 pm Post subject:

Forgot to mention, I pulled hte focus board, no change. I'm on calls today, but will work on it again this afternoon.

Antorsae, I can see that on one set maybe, but on several? I've never seen this on other sets. I do have a good working 8500 right beside it, so I'll swap tubes in the end if nothing else fixes it.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Tim in Phoenix · Joined: 21 Oct 2006 Posts: 4409 Location: Phoenix

Curt

P43 green could behave like that, check the label on the tube.

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