CurtPalme.com Home Theater Forum

ChrisWiggles

Just a reminder. I remember doing this a couple hundred hours in some time ago when there were a number of discussions over at the A/V Sales web-dungeon. Long since forgot about that, things were fine for a long time. Anyway, noticed things were pretty dim lately such that I even kicked my bulb into high a couple weeks ago for a particularly dark movie, and was mainly figuring there was some natural light drop-off as the bulb aged (I'm at ~1190 hours). But I thought I'd take a peek in there to see what was going on.

So I pulled the projector down and yanked the bulb again and sure enough that front plate of the optics was heavily coated with gray sooty grime, along with the front glass element of the bulb assembly. Cleaned that right off, and BOOM there's all my brightness back! By eye looks about twice as bright as before (maybe an exaggeration), which means I was probably losing 75% of my light output. I probably should have done this quite a long time ago...

So folks running JVCs like my RS20: get ye some lens tissue and some cleaning fluid and keep her running nice and bright!

Thumbs Up

WanMan · Joined: 19 Mar 2006 Posts: 10273

I need to do this. While I also read the threads on AVS a while back, I too had forgotten all about it. On some occasions I think the same that a scene or movie appears dark, but then another scene in same movie or the movie in general is concluded dark. One of these days I'll actually overcome my laziness and have a look.

ChrisWiggles · Posted: Tue Apr 17, 2012 7:45 pm Post subject:

Do it do it do it! BIG difference! You should probably do it every few hundred hours. Considering how rarely you have to clean the lens on this thing because of the cover & airflow (I think I only cleaned the lens once), it's a small amount of upkeep compared to my CRT days of converging and re-doing setup and lens cleaning. So it's easy to just let it go by and do nothing, but don't! And run that little air filter under the faucet too for good measure. Shouldn't take more than ten minutes, plus a little bit of dry time for good measure.

It's like a free upgrade! Thumbs Up

**kal** · Posted: Wed Apr 18, 2012 2:14 am Post subject:

I wonder if a lot of the talk of dimming JVC bulbs is due to issues like build-up like this that can be fixed with a cleaning? (Haven't really followed the details, I must admit).

Kal

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

Maybe, but there are a lot of people getting dimming after only a couple of months. One guy on the AVS dimming thread used his JVC on average 7 hours a day since he owned it. That is a lot of hours in a short period of time. I don't think he checked, but I would guess it wasn't a huge build up inside the pj.

ChrisWiggles · Posted: Wed Apr 18, 2012 2:50 am Post subject:

stridsvognen · Guest

I have a JVC DLA X7 who lost from 10FL at 500 hours to 5 FL at 700 hours on the lamp, it was not dirt, on the optics but dirt in the glass tupe inside the lamp.

HogPilot · Posted: Wed Apr 18, 2012 4:46 pm Post subject:

**kal** · Posted: Wed Apr 18, 2012 5:09 pm Post subject:

Interesting. Thanks for the extra info!

Kal

ChrisWiggles · Posted: Wed Apr 18, 2012 5:51 pm Post subject:

And to be clear: you have to clean the glass face of the bulb assembly, AND the square colorful glass plate that the bulb points at (that's the worst part!) from the offgassing/etc.

The glass face of the bulb assembly on mine is actually cracked, but doesn't seem to have any visible impact on anything, so I've ignored it until the bulb needs to be replaced.

WanMan · Joined: 19 Mar 2006 Posts: 10273

Chris, without going back and reading those old threads what did you use to do the cleaning?

**kal** · Posted: Thu Apr 19, 2012 1:43 pm Post subject:

Threads like this are reasons why I'm torn between where I want to go with the digital projector I'm buying in a few months... I'm not sure if I should go with what I want (the JVC RS45 or more expensive RS55) or go with the Sony HW30 or more expensive VW95.

Sony just doesn't seem to have the same problems, but then Sony doesn't have quite the same black level /native contrast ratio that I know I want for excellent film type quality. (Not saying the Sony is 'bad' - it's just different and not what I'm after. The fact that they include an auto-iris goes against my 'principles' too).

I haven't seen any of these in action of course. Which makes it even more confusion. *sigh*. Sorry. Off-topic.

Kal

stridsvognen · Guest

**kal** · Posted: Thu Apr 19, 2012 2:17 pm Post subject:

As the author of the Greyscale & Colour Calibration for Dummies guide, I most certainly have HCFR. Wink

Having to recalibrate every 50 hours is (IMHO) crazy. That's unfortunate. I think most people would like a projector that doesn't have dE's that drift so much that it's noticeable every 50 hours.

dE under 3 or so is fantastic. In fact, under 10 is (again IMHO) acceptable. You want to get as close to 0 as possible of course but that's not always possible. You have to assume the meter's not 100% accurate either unless it's a spectroradiometer or you're using a recently recalibrated colorimeter.

What sort of dE drift are you seeing over the first 180 minutes when it's turned on?

Post the files right here in the thread if you don't mind so that others can see too. Just click "Go Advanced" and then the "Add attachment" option.

Thanks!

Kal

stridsvognen · Guest

Cold

stridsvognen · Guest

30 min

stridsvognen · Guest

60 min.

stridsvognen · Guest

120 min.

stridsvognen · Guest

180 min

stridsvognen · Guest

340 min All with my new lamp at around 50 hours,
And there is a perfectley good reason that the rgb and gamma is not compleetley tight, im trying to controle the placement of the colors, so its ok to start looking a movie after around 45 min.