DLP TV Pulsing? (1 Viewer)

[Khabi]

So I've got a WD 73734 73" DLP television. I do love it and it seems to be a great tv. About a month ago it started acting a little strange.

On the left hand side of the TV the image pulsates from dim to normal. This lasts from the edge to about 1/4 of the total screen. It does it on each input device (HDMI and Component), so its not a problem with those (it does it on my xbox, ps3, and cable box).

Some more info on this:
Turning the TV off and back on fixes this issue for a little bit, but it seems random on how long it does. Sometimes it fixes it for weeks, sometimes for only 10 or so min. When turning the TV off when this is happing, it takes awhile to power off and when it does, the power light blinks for a little while like it does when there is problem.

I'm hoping someone else might have had this issue before I go and pay someone to come out.

 

[Joseph DeMartino]

Sounds like the bulb may be going. How long have you had the TV?

Regards,

Joe

 

[Khabi]

A little over a year now, it was the display model before that (they gave me a really good deal on it).

My understanding was that the whole screen would go dim if the bulb needed replacement. Is that not true? And why would only part of the screen do this? its a fast pulsating too, like dim for one second and bright for one, back and forth like that.

 

[Gregg Loewen]

Id say it is the bulb....
Ive seen many fickle bulbs.

 

[Leo Kerr]

1. it sounds like the lamp.

2. hope it's the lamp, 'cause if it ain't, then it's not gonna be easy (or, it'll be easy but not cheap.)

That said, it's still an arc-lamp of some sort in there, and as arc-lamps age, they can "wander." This happens in the big arcs used for movie-houses, and it happens in the small arcs for home projectors and rear projectors.

(it occurs to me at this point that it might possibly be the lamp's ballast, but seems... much less likely than the lamp itself. Not sure what percentage of the cost is in a ballast for these; hopefully not much.)

Anyway, my quick and dirty guide to projection lamps is sort of as follows: lamps show their age by

• long/slow start-up
• color change (often more green or yellow,) and lower light output
• flicker over the whole image (unstable arc, intensity)
• arc-wander, which also might manifest as a hot-spot that moves around -- although generally in the central area of the image

In certain kinds of arc-lamps, an aging ballast might also manifest through flicker and wander, but shouldn't really be showing up as a slow-start (except as a failed start, with several strike-attempts,) or color-change.

Of course, the catch is, a failing lamp can be hard for a ballast to operate (make the ballast work harder,) and cause the ballast to fail prematurely, or a failing ballast can also kill a good lamp.

My "feel" is, the best way to keep an eye on things and to be able to evaluate the health of these, is to watch the projector start-up. Be familiar with how it behaves.

Leo

 

[Joseph DeMartino]

Quote:

Originally Posted by Khabi

A little over a year now, it was the display model before that (they gave me a really good deal on it).

Which means it was probably running 10 to 12 hours a day for months on end in full "torch mode" with the brightness and contrast turned up to the max to make the picture "pop" on the showroom floor. Depending on how long it was a display model it could easily have had the equivalent of a couple of years' normal wear and tear on the bulb. Since you've now had it for about a year, you should be just about at the end of the bulb's life.

My understanding was that the whole screen would go dim if the bulb needed replacement. Is that not true? And why would only part of the screen do this? its a fast pulsating too, like dim for one second and bright for one, back and forth like that.

I'm not sure what you're understanding is based on, but that's pretty much the opposite of the truth. Bulbs in modern RPTVs do gradually dim over time, and shift color as Leo mentioned (my set turned slightly green when the bulb was nearing the end of its life.) But when they get very close to burning out entirely they do indeed arc strangely, shifting in light output while you watch them, and irregularly across the screen. Trust me, I have an LCoS RPTV of my own and my nephew has a Samsung DLP and I've been through a couple of bulb changes. That's why I immediately said, "It's the bulb" when I read the symptoms you described.

You might want to check prices for your model at these sites:

Direct Merchant

DLP Lamp Xpress

Projector Quest

When I got my set DM was having a sale on JVC bulbs, and I bought two of them because I didn't want to be without a TV for a couple of days (or pay an outrageous amount for overnight shipping) when the bulb eventually went. I wanted to make sure I always had one on the shelf. So far I've replaced the original bulb (after nearly three years.) The great thing about these sets is that once you replace the bulb the picture is basically restored to where it was the day you bought it. When I use my second bulb, I'll order another one or two. (Or maybe I'll order another before then. I check the prices on a couple of bulb sites every so often for both my set and my nephew's DLP and if I find a really good price, I'll buy while the buying is good.)

Regards,

Joe

 

[Khabi]

I figured the TV had most likely been overworked, but getting the floor model put it right in the price range I was willing to pay for a new one (about $600 cheaper).

I'm not sure what you're understanding is based on, but that's pretty much the opposite of the truth.

This is my first real 'high end' television, so its been based on just general experience with bulb and older tv's in general. I'm not second guessing anyone here, I just like to try and get a handle on things like this. I'm a tech buff, but just never had the oppertunity to work with a TV like this, so I kinda have to guess and learn as I go. Hooking them up, basic color adjustments and such are easy. When it comes to the inner workings, I pretty much a retard

So I'm just trying to get some clairification is all. I'd rather learn how it works, then to just blindly follow and hope for the best As an aside, if anyone has any good reference material, I'd love a link.

So I guess my next question is generally how easy are the bulbs to replace? The price on those sites is definatly do-able as far as me picking one up (I'm assuming having someone come out to replace it will at the very least double the cost..). I know its going to range depending on the TV and Manufacture, but is there anything I should watch out for or anything else I should be check on while I've got it open?

 

[Joseph DeMartino]

Swapping the bulbs out should be pretty straight-forward. You manual (or the manufacturer's web site) should show the procedure. Depending on the make and model you may have a choice between a bare bulb and a bulb plus an enclosure. On my TV I got the bare bulbs. In my case the only difference between the two was a couple of screws and I think a plastic gasket. It was very easy to transfer these parts from the original bulb assembly to the new and pop the sucker in.

BTW, to get maximum life out of the new bulb you should definitely calibrate the set with a disc like Digital Video Essentials or a similar consumer calibration disc once you do the installation.

Regards,

Joe

 

[Leo Kerr]

really? Most projectors I've dealt with, apart from the high-end xenon-arcs and the newer dynamic gamma projectors, the lamp is just on, and the brightness and contrast don't do anything to the lamp.

Anyway, yes, if you're looking for best price, you may be able to get bare bulbs, which adds an extra step or two to the process.

Other than that, it's generally take off the cover (1-3 screws), unsecure the lamp (a screw, a quarter-turn knob, or both,) lift the handle and yank it out. Align the new one, shove it in until it makes up, and screw it back down. Put the cover back on, and reset the hour-counter.

The worst part might be just getting to the lamp door. Projectors, most of the time, seem to put them right under the ceiling mounting plate. RPTV type things tend to make it so you have to move the whole thing and rearrange the furniture. (The deck chairs on the Titanic? I dunno; it's been a strange week.)

Anyway, it's not a service call!

Oh, and when you do it, see also if you can find the filters and either clean or replace them. At a minimum, whenever you change the lamp.

Leo