RP - DLP or LCD picture distortion? - Long

Archived from groups: alt.tv.tech.hdtv (More info?)

"bobukcat" <bobukcat@killspam.fuse.net> wrote in message
news:jX_Cd.1471$7k5.3@fe37.usenetserver.com...
> I bought a Mits WD-62725 DLP RP TV before Christmas and watched basically
> nothing but movies and football on it for the first two weeks or so. Then
I
> started watching ESPN on it and noticed that the "Bottom Line" is not
> straight across the bottom of the screen. I verified this was true on
other
> sources as well as other channels that display a straight line across the
> bottom. I called the service department at HHGregg where I bought it and
> they sent a guy out Tuesday. He started out by shaking the hell out of the
> set which didn't make me real happy, apparently this is their method for
> fixing a "shifted mirror" in shipping. When that didn't fix it he called
> someone to find out what adjustments there are and worked for a while to
get
> the bottom line straight - while displaying the cross-hatch we noticed
that
> there is a slight downward bow on about the bottom 1/5 or so of the
screen.
> No matter how much he adjusted it, to get the bottom line to appear as
> straight as possible it resulted in a line across the top being tilted
down
> by about 1/4 inch over the width of the screen, and the very middle of the
> picture bows down at the bottom. The problem with the top line is
extremely
> noticeable anytime programming, or the on-screen guide, with a straight
line
> across the top is displayed. He said this is the best he can do and he
would
> call Mits and get back to me, he called later with a number for me to call
> Mits. I called them and they have no idea why this guy told me to call
them,
> said that it's obviously a problem with the set that the retailer should
be
> responsible for fixing it. So, I called HHGregg, got the manager and they
> said it was the service guy's determination that this level of error was
> "within the manufacturer's spec" but they would send another tech out to
> look at it this Friday. Here's my question - is there some level of pictur
e
> bow that is considered acceptable in a RPTV, and if so what is it? The
> owner's manual goes to great lengths to point out that up to .01% of fixed
> pixels is considered within spec, but nothing at all about picture
> distortion such as this. I say it's total BS and will happily dump this
set
> back at store unless they fix / replace it, seems to me like it has to be
a
> lens or actual screen problem - anyone have any similar experiences with
DLP
> or LCD RP TVs???
>
> Sorry for the length of the post!!
>
> Bob K.

If the picture is bowed, it is because the cabinet of the set is not holding
the screen and or mirror properly. The tech may have made it worse if he
was excessive in his shaking. There are no adjustments for bow and no specs
for acceptable bow. If you are unhappy with it you need to complain to both
Mitsubishi and the dealer. Mitsubishi is very responsive to consumer
complaints and may want to have another ASC look at it.

A problem with many of the new DLP and LCD sets, and to some degree newer
CRT based sets (all RPTV), is that the cabinets are all plastic and very
flexible. One price paid for reducing the weight is less physical
stability. I have seen two Mitsubishi DLP sets that came out of the box
with a tilt. The first thing that should be checked is that the surface
that it is on is flat. A table that is not flat can create tilt and even
bow problems on many sets.

Your tilt, and/or keystone, problem is easily adjusted. Figuring out the
bow might be more complicated. If the tech did not fix the tilt it was
because he did not understand the set very well or is an idiot. There is
nothing about the DLP engine that would be suspected of creating this and is
most likely mirror or screen mounting related. I would start by taking the
screen off and inspecting the cabinet carefully then remounting it if I were
doing the service.

Leonard

Archived from groups: alt.tv.tech.hdtv (More info?)

"bobukcat" <bobukcat@killspam.fuse.net> wrote in message
news:jX_Cd.1471$7k5.3@fe37.usenetserver.com...
> I bought a Mits WD-62725 DLP RP TV before Christmas and watched basically
> nothing but movies and football on it for the first two weeks or so. Then
I
> started watching ESPN on it and noticed that the "Bottom Line" is not
> straight across the bottom of the screen. I verified this was true on
other
> sources as well as other channels that display a straight line across the
> bottom. I called the service department at HHGregg where I bought it and
> they sent a guy out Tuesday. He started out by shaking the hell out of the
> set which didn't make me real happy, apparently this is their method for
> fixing a "shifted mirror" in shipping. When that didn't fix it he called
> someone to find out what adjustments there are and worked for a while to
get
> the bottom line straight - while displaying the cross-hatch we noticed
that
> there is a slight downward bow on about the bottom 1/5 or so of the
screen.
> No matter how much he adjusted it, to get the bottom line to appear as
> straight as possible it resulted in a line across the top being tilted
down
> by about 1/4 inch over the width of the screen, and the very middle of the
> picture bows down at the bottom. The problem with the top line is
extremely
> noticeable anytime programming, or the on-screen guide, with a straight
line
> across the top is displayed. He said this is the best he can do and he
would
> call Mits and get back to me, he called later with a number for me to call
> Mits. I called them and they have no idea why this guy told me to call
them,
> said that it's obviously a problem with the set that the retailer should
be
> responsible for fixing it. So, I called HHGregg, got the manager and they
> said it was the service guy's determination that this level of error was
> "within the manufacturer's spec" but they would send another tech out to
> look at it this Friday. Here's my question - is there some level of pictur
e
> bow that is considered acceptable in a RPTV, and if so what is it? The
> owner's manual goes to great lengths to point out that up to .01% of fixed
> pixels is considered within spec, but nothing at all about picture
> distortion such as this. I say it's total BS and will happily dump this
set
> back at store unless they fix / replace it, seems to me like it has to be
a
> lens or actual screen problem - anyone have any similar experiences with
DLP
> or LCD RP TVs???
>
> Sorry for the length of the post!!
>
> Bob K.

Some distortion in the linearity of the picture is always going to be there,
nothing is perfect. BUT it shouldn't be noticeable when viewing a picture.
Probably will be noticeable when displaying the grid pattern. Have some
patience with service guys as they are seeing these problems for the first
time.

Some things to check that the servicer may not have thought of. Is the
mirror bowed? A sheet of thin glass (mirror) can bow if pressure is applied
to it, or it's not supported. Since the image is still expanding as it
leaves the mirror the bow error is magnified before it hits the screen.

Serviceability is an issue with these new LCD and DLP sets. It may be
impossible for the servicer to determine where the problem is as he can't
examine the light path without dissassembleing the set and then he can't
examine the light path because he has disassembled the set.

The disadvantage of the current crop of DLP and LCD sets is their lower
resolution (low picture element number (around 720P) but the advantage is
supposed to be their focus, convergance registration and linearity to say
nothing of their immunity to phosphor aging and reliability.