CurtPalme.com Home Theater Forum

[CRT_Ben]

Hey guys,

I've been running my PJ for anywhere from 3-7 hours a night now, playing Halo 3 8) and I noticed that my blue tube VNB is getting much hotter than the rest. Currently, I have the plastic tube housings off (which I know are important to direct air to cool the VNBs), but the PJ is also fully opened up, with the top off and the rear heatsink flipped down. I can try to get my dad's laser pyrometer (sp?) to see how hot it's getting, but if I press my fingers on the VNB heatsink it gets extremely uncomfortable after about 3-5 seconds, and it might actually burn me if I kept them on longer. The Green and Red heatsinks, while hot, I feel like I could keep my fingers on them indefinately without burning myself. The rear heatsink over the convergence and stig amp is about the same, hot but not burning hot.

Is my blue VNB running too hot? There aren't any indications of burning where the big resistors meet the VNB, at least not yet.

Thanks!
Ben

[jamieh]

Ben
I don't think you should be running that marquee for 3-7 hours with the tube housings off. I'm assuming you've seen the large holes in the bottom of those housing's for bringing the air up from the belly fans and the holes at the neck board are exit holes for the same air. Most of us call that forced cooling.....lol These machines are designed to run 24/7 and with the all the covers on to make sure the cooling air from those fans get to were its needed. One neckboard running hotter than than another might not mean anything bad, it could just mean one tube is being driven harder than another. Since you said there's no discoloration on those big resistors i'd put them covers back on and let the machine be.
Seven hours a night playing Halo 3!!....thats hardcore man...i need to check that game out...lol

[tse]

If you can handle running games with a warmer color temperature you could copy your set-up to another recall, switch to that recall, and turn the blue drive down. Play games in that recall and switch back to the original for other stuff. The hotter the cards run the more likely there will be failures.

Scott

[garyfritz]

I'll bet your rear heat sink was getting plenty hot too. Galen (zGman) on the A site explained how important it is to have ALL the parts in place -- tube shrouds, covers, even the front foam around the lenses!! -- in order to get proper cooling. Try putting the covers back on, maybe with a temp probe on the VNB, and things should run a lot cooler.

[mp20748]

I run my mods after a significant change with the covers off the tube assembly. I've found that to be the best way to make sure the changes will hold up under heat. I do this test to see how hot they get without the forced air cooling. And the test must past the 24 hour without cooling mark.

now, this is what happens with my testing.. If the heat sink is too hot to touch in about 60 seconds, with no image on the tubes, the neck board has a defect. If the heat sink runs hotter than the other two, the neck board has a defect.

All in all, the projector should operate with the neck boards being warm to the touch at any giving period of time with the cooling in place, and nothing no image on the tubes.

And do note that the neck boards can run hot to the touch, but that should happen only when you're running high scan rate signals into it, and it also depends on the image that's on that high scan rate signal. A busy (signal with a lot of very small detail in it) could cause the board to run hot to the touch. lower scan rates or higher scan rate signals that are not busy. Should not make the boards hot to the touch.

So if your neck board is hot to the touch with the covers off, and you're hot running a busy 1920x1080P signal, but something lower, that neck board is more likely defective...


At least this is what happens when I test my boards. And should also be a good way to test any neck boards of a marquee.

Chances are, that neck board that's running hot, will not handle the higher scan rates and bandwidth of one that does not have the same heat problem.

I wouldn't be concerned with it damaging the tube. I would be concerned with it finally failing, or not performing up to the level of the other two boards. Plus there's a risk of it not holding a color balance.

A quick test to check it out is to use the internal test pattern for this, would be to go into the MENU -> PIC 1 -> 6 -> 5 or 6, and then on the remote 'Press' in sequence 1 then 2 then 3..

each color should display, with 1 being red, 2 green and blue 3 - look carefully at both vertical and horizontal lines in the grid, and see if each color has the same lumens on both vert and horz lines.

The blue neck board would more likely show diminished vertical lines if defective, but not necessarily. because it is running hot to the touch and it's temperature is hotter than the other two, it should be replaced regardless.

[CRT_Ben]

Hey guys,

Thanks for the advice. I do know that the tube housings are used to force air over the neckboards, but I also heard somebody say once that if you ran with the covers off it'd probably be alright. I just need to get around to cutting my 8" tube housings to fit the 9" tubes.

Mike - I'm running 720p currently, and yes there's usually quite a lot of detail on screen. Also, I'm not sure if you've played Halo, but it has quite a blue theme going on so the blue tube might be getting more of a workout than usual. I can do your test however of running the set with no image from a cold startup and see if the blue VNB gets hotter than the rest, that will let us know if there's something wrong with it.

For now, until I get my housings modified (not hard, I know, but I'm super busy with work and want to get more Halo 3 out of my system before I take my PJ down), I'll probably just use a large floorstanding fan pointing at the neckboards. Any anticipated issues with doing that?

Thanks!
Ben