CurtPalme.com Home Theater Forum

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

I have been having a difficult time getting a flat greyscale after installing HD144 lenses to my Marquee 8500. I can not get a whit field to be white with out raising blue drive up to the 80's and have red and green drives below 5, this just seems way to low for the drives of the red and green. Also i get a a hump in the blue from 30 to 70 IRE i think because of this. I read Tim's greyscale set up where he mentions any drive higher than 75 for blue means a weak tube, could this be the problem?
Any one out there with a HD144 equiped marquee willing to tell me what their Drive and G2 numbers are so I can get
a general idea of what they should be. Is there any other way to check blue tube output? it also seems a bit softer than the rest of the tubes try to focus it properly before defocusing it to set greyscale.

Athanasios

Tom.W · Joined: 09 Mar 2006 Posts: 6635

Do they have built in Red and Green filters ? If so you need to readjust the Gray scale.

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

Tom.W · Joined: 09 Mar 2006 Posts: 6635

The Red and Green filters reduce light output on Red and Green so you need to also reduce the Blue output for the proper balance. How many hours on the tubes ?

Gino · Posted: Wed Apr 30, 2008 2:08 am Post subject:

Have you tried blue defocus?

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

Not sure the hours on the tubes is reliable as the Projector says its Reference 8(PSI Projector) But none of the 8500 PSi modded boards were in it. The person I go it from must have scavanged the good boards and put in some boards from an 8000. I know the neck boards were the only PSI boards left. The set said 45 hours so i think who ever had it before me must know the super secrete service menu code and changed it. Also I Know the red was a VDC rebuild as it has the sticker on it, so other tubes could also be rebuilds.
Gino , I have tried the defocus but get a decent increase where i can lower the drive settings the grid line's get close to an inch wide way way to much.

Is there a way besides the characteristics Tim mentions on his web site for checking the emission of the tube, some kind of scope test from any of the tube pins?

I could just try another tube as i have a few spares that have hardly any visible wear but not in the mood to do the whole spring compression thing.

Athanasios

Tom.W · Joined: 09 Mar 2006 Posts: 6635

Try this thread.

https://www.curtpalme.com/forum_archived/viewtopic.php@t=10109.html

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

The thing is before i did the lens change it seamed ok with the internal step pattern. Then once i took it all apart to add the HD 144's, and started to watch it the colors were off
as they should have been with the colored lenses. Trying to do the step pattern by eye i could never get this green tint out of the white bars. I can get great grey in between but the last two bars would have a green tint even with the green drive set to 0. Could i have not noticed the weak blue before with all clear lens's and now that the colored ones are in it would pronounce the possible fault in the blue even though its output seamed fine before the lens change?

Tom thanks for the read, i watched that thread, and the pdf on the sencore 7000 was very informative. When the tube was out i could have got some crud loose and into the cathode. Not sure though.

It could be that i just need to find the right setting for all the G2's and drives, but he 0 setting for red and green just dont sit with me well as at some ire's i cant go lower for them when i need to.

Athanasios

**Curt Palme** · Posted: Wed Apr 30, 2008 6:31 am Post subject:

From the swaps I've done (two sets of 144s on Marquees so far, and playing with color filters, your color balance to the naked eye shouldn't be out THAT far. I'm guessing some problem crept into the set as you were working on it? Can you throw the HD8s back on to test that theory?

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

I would have to take out the adaptors as they are the old style, kind of a pain but i have another set od HD 144 i could put the clear from that set on the green as that is the tint to the high end i see. One thin i noticed also it seems the blue doesnt focus as well as the green and red. red is super sharp. even with different FCM . That is another reason i think its a slightly weak tube. I have a feeling its strong enough for clear tubes on the greeen and red but needs a full emission for the HD144 colors.

Athanasios

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

Well I tried the raster test with two Vims:
1)my old modded vim : set my g2's and drives to Tims settings on his site
then ramped up brightness and lowed contrast to show raster green ok ,and red very bright , blue barely visable.

2)stock 20035-03p vim: Tims settings again,Green good,red good(lower than my moded vim) blue on but not nearly as bright as red or Green

So I left the unmodded vim in and just did a quick grey scale using my EYE one and HCFR. I get nice and flat red and green but blue dips below 20 goes way up from 30 to 70, 80 is spot on and then drops like a rock for 90 and 100. The readings for the tube with that greyscale are G2 64 Drive 85!!! so i bumped it up to 100 and i still get the drop from 80-100 with 80 being right on.

I think its the tube and Also i need to look at my modded vim as it seems to push red higher and lower blue a little.

So with the info on the G2 and Drive setting for my unmodded VIM do you think its slightly weak tube.

Athanasios