A pal has an awfully expensive home cinema set up - perhaps 5 years old.
The projector is an Italian DLP type (can't remember the make) which cost
the thick end of 10 grand. Most of the rest is badged Linn. The firm who
installed it all (nice job) are no longer around.
The output from the projector was getting a bit dim so he decided a new
lamp was needed. The quote from a dealer was 1200 quid. ;-) He got the
lamp from Ebay for less than half that and asked me to fit it, as he
doesn't know one screwdriver from another. ;-(
Proved an easy job - but I suspect the dealer would have done a good clean
at the same time. And I wasn't going to attempt a full strip down without
a service manual - not available. So just carefully cleaned everything I
could including the various fans.

The light output is now fine - but it seems he hoped it would cure another
fault. That is moving 'diagonal' wavy lines - looks to me like RF
interference.

If you put up the various test patterns internal to the projector, these
are clean. Just the DVD (the only source) has this patterning.

The whole installation is built in and will need quite some dismantling to
get at anything - even just to try a different DVD player.

The strange thing is it appears to use the S-Video input to the projector
- since it has DVI and components.

Anyone come across this sort of fault before I start ripping things apart?

--
*Time flies like an arrow. Fruit flies like a banana.*

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:

The light output is now fine - but it seems he hoped it would cure another
fault. That is moving 'diagonal' wavy lines - looks to me like RF
interference.

....

The strange thing is it appears to use the S-Video input to the projector
- since it has DVI and components.

Anyone come across this sort of fault before I start ripping things apart?


"dlp wavy lines" seems a popular search term in Google, which suggests
it's not a unique problem. Mitsubishi & Samsung feature highly, but
haven't looked further into the posts for answers.

http://forum.ecoustics.com/bbs/messages/2/295634.html

Probably try posting to sci.electronics.repair ?

--
Adrian C

In article ,
Adrian C wrote:
"dlp wavy lines" seems a popular search term in Google, which suggests
it's not a unique problem. Mitsubishi & Samsung feature highly, but
haven't looked further into the posts for answers.

If it were a DLP fault, wouldn't they appear on the menu or internal test
charts, etc?

Looking at that forum, it appears to be only analogue inputs are
affected (on a different make) so it could still be RF interference,
rather than a fault.

--
*The most common name in the world is Mohammed *

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
A pal has an awfully expensive home cinema set up - perhaps 5 years old.
The projector is an Italian DLP type (can't remember the make) which cost
the thick end of 10 grand. Most of the rest is badged Linn. The firm who
installed it all (nice job) are no longer around.
The output from the projector was getting a bit dim so he decided a new
lamp was needed. The quote from a dealer was 1200 quid. ;-) He got the
lamp from Ebay for less than half that and asked me to fit it, as he
doesn't know one screwdriver from another. ;-(
Proved an easy job - but I suspect the dealer would have done a good clean
at the same time. And I wasn't going to attempt a full strip down without
a service manual - not available. So just carefully cleaned everything I
could including the various fans.

The light output is now fine - but it seems he hoped it would cure another
fault. That is moving 'diagonal' wavy lines - looks to me like RF
interference.

If you put up the various test patterns internal to the projector, these
are clean. Just the DVD (the only source) has this patterning.

The whole installation is built in and will need quite some dismantling to
get at anything - even just to try a different DVD player.

The strange thing is it appears to use the S-Video input to the projector
- since it has DVI and components.

That's poor, I assume since you have replaced the lamp, you can gain access
to the component video and DVI ports?

I would run new component and HDMI cables if at all practical - sounds like
it will be a HD PJ, and SVideo is poor compared to component or DVI/HDMI
I have an old Sony that was damn expensive when I bought it, that is about 6
years old and does 1080i over the component video ports (no DVI or HDMI)

To test, just try a short component video cable.

Toby...

"Dave Plowman (News)" wrote in message
...
A pal has an awfully expensive home cinema set up - perhaps 5 years old.
The projector is an Italian DLP type (can't remember the make) which cost
the thick end of 10 grand. Most of the rest is badged Linn. The firm who
installed it all (nice job) are no longer around.
The output from the projector was getting a bit dim so he decided a new
lamp was needed. The quote from a dealer was 1200 quid. ;-) He got the
lamp from Ebay for less than half that and asked me to fit it, as he
doesn't know one screwdriver from another. ;-(
Proved an easy job - but I suspect the dealer would have done a good clean
at the same time. And I wasn't going to attempt a full strip down without
a service manual - not available. So just carefully cleaned everything I
could including the various fans.

The light output is now fine - but it seems he hoped it would cure another
fault. That is moving 'diagonal' wavy lines - looks to me like RF
interference.

If you put up the various test patterns internal to the projector, these
are clean. Just the DVD (the only source) has this patterning.

The whole installation is built in and will need quite some dismantling to
get at anything - even just to try a different DVD player.

The strange thing is it appears to use the S-Video input to the projector
- since it has DVI and components.

Anyone come across this sort of fault before I start ripping things apart?

I have some, no I wouldn't know what to say without knowing what it is.
the stuff I used and frequently had to realign was based on CRTs and
multiple projectors on one screen!

I would suggest that a £30 hdmi DVD player from ASDA is going to be
significantly better image quality than what he has if you are taking it
apart.
Control of said player will be the stumbling block as it cost cash for
players with control interfaces which are probably being used.

In article ,
Toby wrote:
The strange thing is it appears to use the S-Video input to the
projector - since it has DVI and components.

That's poor, I assume since you have replaced the lamp, you can gain
access to the component video and DVI ports?

I would run new component and HDMI cables if at all practical - sounds
like it will be a HD PJ, and SVideo is poor compared to component or
DVI/HDMI I have an old Sony that was damn expensive when I bought it,
that is about 6 years old and does 1080i over the component video ports
(no DVI or HDMI)

To test, just try a short component video cable.

I'm going round tonight to investigate - but it seems it uses a convertor
box at the screen end where the DVD/surround amp is - to feed the
projector via the VGA input. But the DVD is connected to that by S-Video.
Gawd knows why. The convertor box has an composite input so I'll take my
colour bar generator and see if that is clean. Then investigate if I can
improve things over S-Video - although to be fair it looked pretty good
when I've seen it working properly.

Don't think it does the full 1080 - only 720p

The fault seems to be heat related - it starts out clean then the
'interference' gradually appears over some 10 minutes or so. Possibly a
cap failing somewhere.

--
*Why is 'abbreviation' such a long word?

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
A pal has an awfully expensive home cinema set up - perhaps 5 years old.
The projector is an Italian DLP type (can't remember the make) which cost
the thick end of 10 grand. Most of the rest is badged Linn. The firm who
installed it all (nice job) are no longer around.
The output from the projector was getting a bit dim so he decided a new
lamp was needed. The quote from a dealer was 1200 quid. ;-) He got the
lamp from Ebay for less than half that and asked me to fit it, as he
doesn't know one screwdriver from another. ;-(
Proved an easy job - but I suspect the dealer would have done a good clean
at the same time. And I wasn't going to attempt a full strip down without
a service manual - not available. So just carefully cleaned everything I
could including the various fans.

The light output is now fine - but it seems he hoped it would cure another
fault. That is moving 'diagonal' wavy lines - looks to me like RF
interference.

If you put up the various test patterns internal to the projector, these
are clean. Just the DVD (the only source) has this patterning.

The whole installation is built in and will need quite some dismantling to
get at anything - even just to try a different DVD player.

The strange thing is it appears to use the S-Video input to the projector
- since it has DVI and components.

Anyone come across this sort of fault before I start ripping things apart?

--
*Time flies like an arrow. Fruit flies like a banana.*

Dave Plowman London SW
To e-mail, change noise into sound.

From your description it will likely be a "SIM2" IIRC, possibly even a
3-chip at that price, not that that makes a whole lot of difference in this
case. For sure (well 99.9% sure) the problems you state aren't anything to
do with the DLP-ness, ie the digital back end but rather the analogue front
end. Standard analogue video rules apply so it's likely to be either board
level interference or something dying around the A/D or the PSU.

I'm not clear what you mean about the DVI/S-video but if you are saying that
the projector has a DVI input then the very best thing you can do by far is
to use it. It avoids all of the analogue front end nastiness and (should,
provided the projector is designed well) map the pixels directly onto the
DMD so no sampling and resize sillies. If the DVI is talking EDID to the
player and the player is listening (both of which should be the case but
it's a 50/50 call as many manufacturers don't follow the rules) the player
should output the right size image so no resizing. Check that though as
it's a common problem. A really good test of whether you have it right is
to display a pattern from your source which is pixel-on/pixel off (a very
fine checkerboard), if it's set up right it will look good, if it's not you
will see resize bands in the image.

Too late to tell you now but many lamps can be a bit dangerous if you don't
handle them correctly, I guess you survived! If your friend isn't a smoker
and doesn't use stage smoke then cleaning the filters should be all you need
to do. If there are smoke/grease deposits then you are a bit stuffed
without specialist kit as cleaning the prism and DMD(s) is v.diff

Good luck,
Calvin

In article ,
Calvin Sambrook wrote:
From your description it will likely be a "SIM2" IIRC, possibly even a
3-chip at that price, not that that makes a whole lot of difference in
this case. For sure (well 99.9% sure) the problems you state aren't
anything to do with the DLP-ness, ie the digital back end but rather
the analogue front end. Standard analogue video rules apply so it's
likely to be either board level interference or something dying around
the A/D or the PSU.

Think SIM2 rings a bell.

I've just come back from testing things, and my colour bar generator into
one of the composite inputs gives the problem - so it is the projector
itself.

I'm not clear what you mean about the DVI/S-video but if you are saying
that the projector has a DVI input then the very best thing you can do
by far is to use it.

Oh, indeed. However now I've sussed out the system it's not possible. The
rest of the installation consists of a Linn (spit) home movie thingie -
with built in DVD and surround amps. And the best that can output is
S-Video. The SCART on it doesn't give RGB. There are some strange looking
connecters which are for connection to other Linn things. Look like RG45
or similar. Other versions of this unit do output components, though, by
the handbook. If there is a later version presumably HDMI.

It avoids all of the analogue front end nastiness
and (should, provided the projector is designed well) map the pixels
directly onto the DMD so no sampling and resize sillies. If the DVI is
talking EDID to the player and the player is listening (both of which
should be the case but it's a 50/50 call as many manufacturers don't
follow the rules) the player should output the right size image so no
resizing. Check that though as it's a common problem. A really good
test of whether you have it right is to display a pattern from your
source which is pixel-on/pixel off (a very fine checkerboard), if it's
set up right it will look good, if it's not you will see resize bands
in the image.

Right. But he's not about to spend serious money replacing everything else
other than the projector.

Too late to tell you now but many lamps can be a bit dangerous if you
don't handle them correctly, I guess you survived!

Know that one. Was careful not to touch it - but it is built into a glass
or whatever box with a plastic mounting frame. Hence the cost, I'd guess.
I didn't even need to get the cotton gloves out. ;-)

If your friend
isn't a smoker and doesn't use stage smoke then cleaning the filters
should be all you need to do.

Didn't even find any filters so confined the cleaning to using a camel
hair brush and vacuum on the bits I could get at.

If there are smoke/grease deposits then
you are a bit stuffed without specialist kit as cleaning the prism and
DMD(s) is v.diff

Don't suppose you can recommend a fixer? SIM or whoever don't seem keen on
supplying spares and manuals otherwise I might have had a go at changing
the board - assuming it's not all in one.

--
*Always remember you're unique, just like everyone else.

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...


The fault seems to be heat related - it starts out clean then the
'interference' gradually appears over some 10 minutes or so. Possibly a
cap failing somewhere.

Have you or anyone else cleaned the filters on the projector?
They need to be done frequently.

"Dave Plowman (News)" wrote in message
...


Right. But he's not about to spend serious money replacing everything else
other than the projector.

How big is the screen?
These days you can get big lcd/plasma sets.

If you/he do decide to replace it buy a good AV amp with built in D/A
convertors and then the cheapest bluray player will give the same sound and
picture as the most expensive.
It is only the D/A that makes any real difference to how it sounds, not the
label on the DVD player.
Also a digital image doesn't depend on the DVD player either unless it is
upscalling which you shouldn't need to do.

"Dave Plowman (News)" wrote in message
...
In article ,
Calvin Sambrook wrote:
From your description it will likely be a "SIM2" IIRC, possibly even a
3-chip at that price, not that that makes a whole lot of difference in
this case. For sure (well 99.9% sure) the problems you state aren't
anything to do with the DLP-ness, ie the digital back end but rather
the analogue front end. Standard analogue video rules apply so it's
likely to be either board level interference or something dying around
the A/D or the PSU.

Think SIM2 rings a bell.

I've just come back from testing things, and my colour bar generator into
one of the composite inputs gives the problem - so it is the projector
itself.

Sorry, I didn't mean it wasn't the projector I was mentaly splitting the
projector into an analogue front end and a digital back end as they are
radically different parts of a DLP. The digital stuff from the A/D right
through to the DMD is very unlikely to give anything wavy and certainly not
anything crawling through. Those sorts of thing are however characteristic
of faults in the analouge domain.

In a relatively cheap DLP [trust me 5 years ago £10k for a DLP was at the
cheap end] I wouldn't expect massively complex analogue circuitry which is
good news really as it means there's less to go wrong. You have seen the
effect with two sources and presumably two different leads. The composite
and the S-VIDEO almost certainly get commoned together very early on inside,
maybe even simply wire-ored together, you can test for that easily. Between
the connector and the A/D there's probably only a small collection of
components - some ESD protection if you're lucky, a DC blocking cap, a 75R
termination bridge and into the A//D I'd guess.

The other likely area for noise introduction is the power supply. Just like
in a PC the power supply is a highly stressed component and as it starts to
fail it can introduce noise into the supplies to the PCB. Obviously noise
around the analogue parts is not good and esspecially so around the A/D.
Insufficient or failing smoothing caps on the PCB can contribute to problems
(or rather not remove them as they should). I don't know this projector at
all but some have a PSU for the lamp and another for the electronics whereas
some combine the two for cost reasons. WARNING: Lamp PSUs can and will bite
very hard, they put out thousands of volts to start the lamp and then lots
of current to keep it going. Don't go there.


I'm not clear what you mean about the DVI/S-video but if you are saying
that the projector has a DVI input then the very best thing you can do
by far is to use it.

Oh, indeed. However now I've sussed out the system it's not possible. The
rest of the installation consists of a Linn (spit) home movie thingie -
with built in DVD and surround amps. And the best that can output is
S-Video. The SCART on it doesn't give RGB. There are some strange looking
connecters which are for connection to other Linn things. Look like RG45
or similar. Other versions of this unit do output components, though, by
the handbook. If there is a later version presumably HDMI.

It avoids all of the analogue front end nastiness
and (should, provided the projector is designed well) map the pixels
directly onto the DMD so no sampling and resize sillies. If the DVI is
talking EDID to the player and the player is listening (both of which
should be the case but it's a 50/50 call as many manufacturers don't
follow the rules) the player should output the right size image so no
resizing. Check that though as it's a common problem. A really good
test of whether you have it right is to display a pattern from your
source which is pixel-on/pixel off (a very fine checkerboard), if it's
set up right it will look good, if it's not you will see resize bands
in the image.

Right. But he's not about to spend serious money replacing everything else
other than the projector.

Too late to tell you now but many lamps can be a bit dangerous if you
don't handle them correctly, I guess you survived!

Know that one. Was careful not to touch it - but it is built into a glass
or whatever box with a plastic mounting frame. Hence the cost, I'd guess.
I didn't even need to get the cotton gloves out. ;-)

If your friend
isn't a smoker and doesn't use stage smoke then cleaning the filters
should be all you need to do.

Didn't even find any filters so confined the cleaning to using a camel
hair brush and vacuum on the bits I could get at.

If there are smoke/grease deposits then
you are a bit stuffed without specialist kit as cleaning the prism and
DMD(s) is v.diff

Don't suppose you can recommend a fixer? SIM or whoever don't seem keen on
supplying spares and manuals otherwise I might have had a go at changing
the board - assuming it's not all in one.


I can't I'm afraid - not my area of expertise. I'm surprised you can't get
spares for a 5 year old projector though.

"dennis@home" wrote in message
...

"Dave Plowman (News)" wrote in message
...


Right. But he's not about to spend serious money replacing everything
else
other than the projector.

How big is the screen?
These days you can get big lcd/plasma sets.

If you/he do decide to replace it buy a good AV amp with built in D/A
convertors and then the cheapest bluray player will give the same sound
and picture as the most expensive.
It is only the D/A that makes any real difference to how it sounds, not
the label on the DVD player.
Also a digital image doesn't depend on the DVD player either unless it is
upscalling which you shouldn't need to do.

Sure you've checked who you're replying to?

"dennis@home" wrote in message
...


"Dave Plowman (News)" wrote in message
...

Right. But he's not about to spend serious money replacing everything
else
other than the projector.

How big is the screen?
These days you can get big lcd/plasma sets.


IMO if he's got used to a DLP projector he'll be bitterly disappointed by
the image quality of a plasma and probably cry at an LCD. 3-chip DLP is the
dog's wotsits. Even 1-chip from 5 years ago is very good, certainly lots
better than plasma or LCD in terms of artefacts like noisy blacks, black
detail and refresh rate.

Mind you prices have fallen a lot so a new DLP of similar light output and
capability might be a sensible option for anyone serious about home cinema.

If you/he do decide to replace it buy a good AV amp with built in D/A
convertors and then the cheapest bluray player will give the same sound
and picture as the most expensive.
It is only the D/A that makes any real difference to how it sounds, not
the label on the DVD player.
Also a digital image doesn't depend on the DVD player either unless it is
upscalling which you shouldn't need to do.


Nowadays you'd be crazy to go to analogue at all, it's pointless.

In article ,
Calvin Sambrook wrote:
I've just come back from testing things, and my colour bar generator
into one of the composite inputs gives the problem - so it is the
projector itself.

Sorry, I didn't mean it wasn't the projector I was mentaly splitting the
projector into an analogue front end and a digital back end as they are
radically different parts of a DLP.

No - I understood that bit ok.

The digital stuff from the A/D right through to the DMD is very unlikely
to give anything wavy and certainly not anything crawling through.
Those sorts of thing are however characteristic of faults in the
analouge domain.

My thoughts too since the internally generated test patterns are fine. I
couldn't check the DVI input to the beast easily - as there was nothing
there that had one. But I'm sure there could be a fault on the analogue
inputs but not on the digital.

In a relatively cheap DLP [trust me 5 years ago £10k for a DLP was at
the cheap end] I wouldn't expect massively complex analogue circuitry
which is good news really as it means there's less to go wrong. You
have seen the effect with two sources and presumably two different
leads. The composite and the S-VIDEO almost certainly get commoned
together very early on inside, maybe even simply wire-ored together,
you can test for that easily.

I would hope they were kept separated - not much point in S-Video
otherwise.

Between the connector and the A/D
there's probably only a small collection of components - some ESD
protection if you're lucky, a DC blocking cap, a 75R termination bridge
and into the A//D I'd guess.

The other likely area for noise introduction is the power supply. Just
like in a PC the power supply is a highly stressed component and as it
starts to fail it can introduce noise into the supplies to the PCB.
Obviously noise around the analogue parts is not good and esspecially
so around the A/D. Insufficient or failing smoothing caps on the PCB
can contribute to problems (or rather not remove them as they should).
I don't know this projector at all but some have a PSU for the lamp and
another for the electronics whereas some combine the two for cost
reasons. WARNING: Lamp PSUs can and will bite very hard, they put out
thousands of volts to start the lamp and then lots of current to keep
it going. Don't go there.

Any SMPS can bite hard. ;-)

Without a proper manual I wouldn't attempt a repair on someone else's gear
of this nature. If it were mine and the repair expensive, I probably
would.

[snip]


I can't I'm afraid - not my area of expertise. I'm surprised you can't
get spares for a 5 year old projector though.

I meant that the maker doesn't seem to want to supply apart from to its
dealers, etc.

--
*Xerox and Wurlitzer will merge to market reproductive organs.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
dennis@home wrote:
Right. But he's not about to spend serious money replacing everything
else other than the projector.

How big is the screen?

Didn't measure it - about 8 ft wide.

These days you can get big lcd/plasma sets.

Indeed. The screen comes down to cover one of those. ;-)

--
*I must always remember that I'm unique, just like everyone else. *

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
In article ,
Calvin Sambrook wrote:
The composite and the S-VIDEO almost certainly get commoned
together very early on inside, maybe even simply wire-ored together,
you can test for that easily.

I would hope they were kept separated - not much point in S-Video
otherwise.


Oh you'd be surprised. It's not as bad as it sounds actually and it's
perfectly usual for signals to time-share a track on the PCB, indeed many
A/Ds are pinned that way so designers have no choice. [Mind you most double
up composite with G/Y of component RGB/YUV as it makes more sense that way
in the A/D].
The cheap way is to wire-or in which case the user had better not plug a
signal into both inputs at the same time. The more expensive is to buffer
the two inputs onto the track in which case the user can have both plugged
in and can select between them. In the case of composite sharing with
S-video's Y you still get the advantages of s-video with it's seperate
colour carrier and would never really know what's going on inside.

In message , "Dave Plowman (News)"
writes
In article ,
dennis@home wrote:
Right. But he's not about to spend serious money replacing everything
else other than the projector.

How big is the screen?

Didn't measure it - about 8 ft wide.

These days you can get big lcd/plasma sets.

Indeed. The screen comes down to cover one of those. ;-)


Ha ha

--
geoff

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Dave Plowman (News)"
saying something like:

The output from the projector was getting a bit dim so he decided a new
lamp was needed. The quote from a dealer was 1200 quid. ;-) He got the
lamp from Ebay for less than half that

I know. The retailer prices are a ****ing joke, which has given rise to
many cheaper solutions for several popular projectors.
For his six hundred quid, that would have included the lamp housing, I
suppose, which makes it a slip-out, slip-in fit.
Big difference between that and a HSI-T lamp from Sylvania, which can
often be made to fit PJs, like my old Mitsubishi, with a bit of Dremel
action. Mitsubishi wanted £300, via ebay it was £180, from
www.lampspecs.co.uk it was £15

"Grimly Curmudgeon" wrote in message
...
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Dave Plowman (News)"
saying something like:

The output from the projector was getting a bit dim so he decided a new
lamp was needed. The quote from a dealer was 1200 quid. ;-) He got the
lamp from Ebay for less than half that

I know. The retailer prices are a ****ing joke, which has given rise to
many cheaper solutions for several popular projectors.
For his six hundred quid, that would have included the lamp housing, I
suppose, which makes it a slip-out, slip-in fit.
Big difference between that and a HSI-T lamp from Sylvania, which can
often be made to fit PJs, like my old Mitsubishi, with a bit of Dremel
action. Mitsubishi wanted £300, via ebay it was £180, from
www.lampspecs.co.uk it was £15

Er, no. While I wouldn't defend individual relamp prices as I don't know
the specifics of individual projectors I do know that lamp technology in DLP
is nothing like that used in other projector technologies. DLP demands
really short arcs and very precise alignment if the image on screen is going
to look good. Manufacturers go to a lot of trouble to get it right and if
you're prepared to spend £10k on a projector in order to get a superb image
why on earth would you ruin it at relamp time?

In article ,
Grimly Curmudgeon wrote:
The output from the projector was getting a bit dim so he decided a new
lamp was needed. The quote from a dealer was 1200 quid. ;-) He got the
lamp from Ebay for less than half that

I know. The retailer prices are a ****ing joke, which has given rise to
many cheaper solutions for several popular projectors.
For his six hundred quid, that would have included the lamp housing, I
suppose, which makes it a slip-out, slip-in fit.

Yes it had - making it as you said a simple job to change. But the maker
reckons it's a dealer only job - which begs the question as to why it's in
a housing.

Big difference between that and a HSI-T lamp from Sylvania, which can
often be made to fit PJs, like my old Mitsubishi, with a bit of Dremel
action. Mitsubishi wanted £300, via ebay it was £180, from
www.lampspecs.co.uk it was £15

I didn't examine it to see if the actual bubble could be replaced. But it
had occurred to me. Given the way similar lamps for cars have tumbled in
price.

--
*What was the best thing before sliced bread?

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Calvin Sambrook wrote:
Er, no. While I wouldn't defend individual relamp prices as I don't
know the specifics of individual projectors I do know that lamp
technology in DLP is nothing like that used in other projector
technologies. DLP demands really short arcs and very precise alignment
if the image on screen is going to look good. Manufacturers go to a
lot of trouble to get it right and if you're prepared to spend £10k on
a projector in order to get a superb image why on earth would you ruin
it at relamp time?

Well, I have a Sagem DLP rear projector, and a new lamp for that costs
nothing like 600 quid. And surely any type of projector requires both a
precision light source and optics to give the best results?

--
*Sherlock Holmes never said "Elementary, my dear Watson" *

Dave Plowman London SW
To e-mail, change noise into sound.

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Calvin Sambrook"
saying something like:

Er, no. While I wouldn't defend individual relamp prices as I don't know
the specifics of individual projectors I do know that lamp technology in DLP
is nothing like that used in other projector technologies. DLP demands
really short arcs and very precise alignment if the image on screen is going
to look good. Manufacturers go to a lot of trouble to get it right and if
you're prepared to spend £10k on a projector in order to get a superb image
why on earth would you ruin it at relamp time?

This isn't a DLP one. Even if it was, there's no way I'd pay the rip-off
ruinous prices they want.
The whole re-lamping thing is about diy, and doing it on a budget. As
more used and dirt-cheap lamp-knackered projectors come on to the market
via ebay the like, more people are finding out about alternative lamp
solutions, including DLPs. There's been a significant growth of interest
in the last couple of years and the body of knowledge is expanding
daily.
As you can appreciate, this is world removed from paying £10K on a
gadget and greasing up and bending over for a lamp.

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Dave Plowman (News)"
saying something like:

I didn't examine it to see if the actual bubble could be replaced. But it
had occurred to me.

Via various forums I found sources of the naked lamps, one of which is
this guy... http://diypro.us/lamps.html for LCD re-lamping. I've no
doubt similar can be found for DLPs, but I wasn't searching for those.
I've certainly come across postings about replacing lamps in DLPs with
cheaper versions, so it's being done out there.

"Dave Plowman (News)" wrote in message
...
In article ,
Calvin Sambrook wrote:
Er, no. While I wouldn't defend individual relamp prices as I don't
know the specifics of individual projectors I do know that lamp
technology in DLP is nothing like that used in other projector
technologies. DLP demands really short arcs and very precise alignment
if the image on screen is going to look good. Manufacturers go to a
lot of trouble to get it right and if you're prepared to spend £10k on
a projector in order to get a superb image why on earth would you ruin
it at relamp time?

Well, I have a Sagem DLP rear projector, and a new lamp for that costs
nothing like 600 quid. And surely any type of projector requires both a
precision light source and optics to give the best results?


Yes and no, DLP requires much shorter arc lamps than LCD et al, it's
fundamental to the design. As the arc gets shorter the other complicating
factors get harder to handle so the cost goes up. If you're using a small,
cheap DLP, the sort you might buy in the high street, then the power is
relatively low which makes things significantly easier, the complexity rises
exponentially with power. Compare your friend's projector power consumption
with yours, most of the power goes into the lamp and very little comes out
the lens, then think what's got to happen to keep that internals of the lamp
cool.
With cheaper projectors you're expectations are lower and tolerance to
imperfections higher. You probably feel pleased to have saved a few (lots
of) £s even if the image isn't quite as good. Indeed you may not even
notice.
If you've paid £10k then presumably you want a big, bright image and you
care about the image quality. Things like roll-off where the image gets
darker towards the edges because the lamp isn't aligned quite correctly and
loss of brightness are probably not acceptable after a relamp, certainly not
if you buy an OEM part.

I guess it's a bit like tyres on a car. I don't buy expensive cars, when it
comes to replacing tyres I tend to buy cheap as I'm not looking to get the
last little bit of performance and I can tolerate quite a lack of refinement
if I save cash.
You might buy an expensive performance sports car in which case you'd
probably be quite prepared to pay for expensive tyres in order to keep the
benefits which go with them. Putting cheap tyres on means it doesn't
perform as well so why spend the money on it in the first place?

In article ,
Calvin Sambrook wrote:
I guess it's a bit like tyres on a car. I don't buy expensive cars,
when it comes to replacing tyres I tend to buy cheap as I'm not looking
to get the last little bit of performance and I can tolerate quite a
lack of refinement if I save cash. You might buy an expensive
performance sports car in which case you'd probably be quite prepared
to pay for expensive tyres in order to keep the benefits which go with
them. Putting cheap tyres on means it doesn't perform as well so why
spend the money on it in the first place?

Heh heh - strangely I have Colway remoulds on my old Rover, and they out
perform the previous 'brand' tyres in every way. They grip better wet or
dry, are quieter, and more comfortable. Too soon to say how long they'll
last. But long standing prejudice against re-manufactured tyres means they
sadly have stopped trading.

--
*Shin: a device for finding furniture in the dark *

Dave Plowman London SW
To e-mail, change noise into sound.

"Calvin Sambrook" wrote in message
...
"Dave Plowman (News)" wrote in message
...
In article ,
Calvin Sambrook wrote:
Er, no. While I wouldn't defend individual relamp prices as I don't
know the specifics of individual projectors I do know that lamp
technology in DLP is nothing like that used in other projector
technologies. DLP demands really short arcs and very precise alignment
if the image on screen is going to look good. Manufacturers go to a
lot of trouble to get it right and if you're prepared to spend £10k on
a projector in order to get a superb image why on earth would you ruin
it at relamp time?

Well, I have a Sagem DLP rear projector, and a new lamp for that costs
nothing like 600 quid. And surely any type of projector requires both a
precision light source and optics to give the best results?


Yes and no, DLP requires much shorter arc lamps than LCD et al, it's
fundamental to the design. As the arc gets shorter the other complicating
factors get harder to handle so the cost goes up. If you're using a
small, cheap DLP, the sort you might buy in the high street, then the
power is relatively low which makes things significantly easier, the
complexity rises exponentially with power. Compare your friend's
projector power consumption with yours, most of the power goes into the
lamp and very little comes out the lens, then think what's got to happen
to keep that internals of the lamp cool.
With cheaper projectors you're expectations are lower and tolerance to
imperfections higher. You probably feel pleased to have saved a few (lots
of) £s even if the image isn't quite as good. Indeed you may not even
notice.
If you've paid £10k then presumably you want a big, bright image and you
care about the image quality. Things like roll-off where the image gets
darker towards the edges because the lamp isn't aligned quite correctly
and loss of brightness are probably not acceptable after a relamp,
certainly not if you buy an OEM part.

I don't see why you think the original manufacturers parts are going to be
any better than an "OEM" part.
The original manufacturer is probably not a lamp manufacturer and probably
buys the same "OEM" lamps in the first place.


I guess it's a bit like tyres on a car. I don't buy expensive cars, when
it comes to replacing tyres I tend to buy cheap as I'm not looking to get
the last little bit of performance and I can tolerate quite a lack of
refinement if I save cash.

I guess that says it all.. save cash when its important and potentially life
saving but pay OTT when its to watch a film.

You might buy an expensive performance sports car in which case you'd
probably be quite prepared to pay for expensive tyres in order to keep the
benefits which go with them. Putting cheap tyres on means it doesn't
perform as well so why spend the money on it in the first place?


Vanity in most cases.

"dennis@home" wrote in message
...


"Calvin Sambrook" wrote in message
...
"Dave Plowman (News)" wrote in message
...
In article ,
Calvin Sambrook wrote:
Er, no. While I wouldn't defend individual relamp prices as I don't
know the specifics of individual projectors I do know that lamp
technology in DLP is nothing like that used in other projector
technologies. DLP demands really short arcs and very precise alignment
if the image on screen is going to look good. Manufacturers go to a
lot of trouble to get it right and if you're prepared to spend £10k on
a projector in order to get a superb image why on earth would you ruin
it at relamp time?

Well, I have a Sagem DLP rear projector, and a new lamp for that costs
nothing like 600 quid. And surely any type of projector requires both a
precision light source and optics to give the best results?


Yes and no, DLP requires much shorter arc lamps than LCD et al, it's
fundamental to the design. As the arc gets shorter the other
complicating factors get harder to handle so the cost goes up. If you're
using a small, cheap DLP, the sort you might buy in the high street, then
the power is relatively low which makes things significantly easier, the
complexity rises exponentially with power. Compare your friend's
projector power consumption with yours, most of the power goes into the
lamp and very little comes out the lens, then think what's got to happen
to keep that internals of the lamp cool.
With cheaper projectors you're expectations are lower and tolerance to
imperfections higher. You probably feel pleased to have saved a few
(lots of) £s even if the image isn't quite as good. Indeed you may not
even notice.
If you've paid £10k then presumably you want a big, bright image and you
care about the image quality. Things like roll-off where the image gets
darker towards the edges because the lamp isn't aligned quite correctly
and loss of brightness are probably not acceptable after a relamp,
certainly not if you buy an OEM part.

I don't see why you think the original manufacturers parts are going to be
any better than an "OEM" part.
The original manufacturer is probably not a lamp manufacturer and probably
buys the same "OEM" lamps in the first place.


Sorry, some mix-up over the term OEM. I think it means Original Equipement
Manufacturer, ie. the guys who made the projector. They will of course have
bought the actual bulb from a lamp manufacturer but they will have aligned
it in the housing for you. You may well be able to re-create an identical
thing by buying the *correct* bulb and doing the alignment yourself, indeed
some manufacturers tell you how to align bulbs but bulb replacement is not
easy and can be really dangerous with some bare bulbs.

The discussion had touched on the idea of fitting some other bulb, even a
small difference is likely to have a huge effect which is the point I was
trying to make.


I guess it's a bit like tyres on a car. I don't buy expensive cars, when
it comes to replacing tyres I tend to buy cheap as I'm not looking to get
the last little bit of performance and I can tolerate quite a lack of
refinement if I save cash.

I guess that says it all.. save cash when its important and potentially
life saving but pay OTT when its to watch a film.


That's a bit unfair! I'm not saying fit unsafe tyres to a car, just
"normal", "nothing special". I accept they may not perform as well at the
absolute extreemes of use but then I'm not racing. I'm also not paying OTT
to watch a film, certainly far less than average as I have a hand-me-down
CRT for a telly (which I don't watch much at all anyway).
I accept however that some people value such things and are prepared to pay
for them, be it performance cars or performance projectors.

You might buy an expensive performance sports car in which case you'd
probably be quite prepared to pay for expensive tyres in order to keep
the benefits which go with them. Putting cheap tyres on means it doesn't
perform as well so why spend the money on it in the first place?


Vanity in most cases.

Calvin Sambrook wrote:

I guess it's a bit like tyres on a car. I don't buy expensive cars,
when it comes to replacing tyres I tend to buy cheap as I'm not looking
to get the last little bit of performance and I can tolerate quite a
lack of refinement if I save cash.
You might buy an expensive performance sports car in which case you'd
probably be quite prepared to pay for expensive tyres in order to keep
the benefits which go with them. Putting cheap tyres on means it
doesn't perform as well so why spend the money on it in the first place?


On the owner's group for my car a fairly common term is "TDF", applied
to the tyres often fitted to cars imported from Japan.

It stands for "Taiwanese Ditch Finder".

Andy

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Calvin Sambrook"
saying something like:

The discussion had touched on the idea of fitting some other bulb, even a
small difference is likely to have a huge effect which is the point I was
trying to make.

shrug

The used price of lamp-expired projectors is so cheap now as to make
some experimentation with positioning very worthwhile. Doesn't take a
genius to measure, with a fair degree of accuracy, where the arc is in
the reflector housing and molish a replacement to suit.