Rear Projection CRT - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
Thread Tools
post #1 of 4 Old 09-19-2001, 06:25 PM - Thread Starter
The Dew's Avatar
Join Date: Aug 2001
Location: Virginia Beach Virginia
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
What is the maintenance required for a rear projection CRT, and how much does it usually cost? Is this something that I can without the help of costly professionals?
The Dew is offline  
Sponsored Links
post #2 of 4 Old 09-20-2001, 08:21 PM
AVS Forum Special Member
Sean Nelson's Avatar
Join Date: May 2001
Location: Vancouver BC, Canada
Posts: 3,355
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 25 Post(s)
Liked: 24
I don't own a RPTV, but I've been extensively researching them in preparation for a purchase, so let me attempt to answer your questions.

The kind of maintenance that an RPTV requires is probably best described as a kind of a "tune-up" that you would give a car to keep it running well. If you don't tune your car it will continue to run, but over time it will gradually perform more and more poorly - the same is true of an RPTV.

RPTVs have three "guns" in them that project a red, blue and green image on the screen. To simplify matters somewhat, there are two fundamental things that must be done to these guns to make sure that the picture you see is of the best possible quality:
  • The guns must be properly focused so that the image they project is as sharp as possible.
  • The aiming of the guns must be adjusted so that the overlapping images from all three of them fall in exactly the same place. If the aiming is off, then you get a blurry, colour-edged picture rather like you see in a poorly-printed newspaper. This is called "convergence".

(This is rather oversimplified, and there are many other adjustments that can also be made, depending on how discriminating you are).

To get the best picture, these adjustments should be made after you have first bought the TV and watched it for some period of time, perhaps 100 hours or so. Then, the TV should be readjusted on a periodic basis, perhaps once every year or two, depending on how well it "holds" the adjustments.

Some adjustments you can probably do yourself - there are lots of sources of information available. If you use a search engine like and enter search keywords which include the model number of your television and "calibration" you're sure to find a lot of useful info. There are DVD discs available which contain test patterns you can use to help calibrate your TV - popular ones are called "Avia" and "Video Essentials". They cost around US$50-ish each.

For the more discriminating viewer, there are other adjustments that require special equipment such as colour analyzers. You can hire professionals to perform these adjustments - most people would recommend that you hire an "ISF-Certified" technician ("ISF" stands for "Imaging Science Foundation", see: ). Depending on the depth to which you want to go the cost can range from about $100 to several hundred dollars.

Many people enjoy their RPTVs without any of these procedures, but even a basic calibration will probably make a substantial improvement (I believe in the 80/20 rule - 20% of the effort gets you 80% of the result). It's prudent to perform at least some basic calibration steps because RPTVs "out of the box" are usually set to give an overly-bright picture (this is often referred to as "torch mode") which can cause "burn-in" on your screen (burn-in is a permanent discolouration in the screen where a motionless bright image has been displayed over a long period of time - think of the spots you see after looking at the sun to get an idea how this works).

[This message has been edited by Sean Nelson (edited 09-20-2001).]

[This message has been edited by Sean Nelson (edited 09-20-2001).]
Sean Nelson is offline  
post #3 of 4 Old 09-20-2001, 09:08 PM
Senior Member
M.Hat's Avatar
Join Date: Sep 2000
Location: Alberta
Posts: 404
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
DEW: I'm sure you're aware that there are new LCOS and other chip-based HDTVs that have recently entered, or are now entering the market. They are much lighter than CRT sets (under a hundred pounds), have a much smaller footprint, and they require no convergence or maintenance. Unfortunately, they are new and still quite expensive. The RCA L5000 LCOS HDTV seems to be a good set based on CEDIA reports and seems about the cheapest chip-based HDTV at the moment, but it is still appearing on the market at about $6000, I believe.

If you look around this forum, you can learn everything you need to know about the new LCOS sets and CRT RPTVs. There are great buys on some of the great CRT RPTVs and they will be much cheaper, despite the convergence costs.

I bought myself a relatively inexpensive 36 inch HDTV direct view to hold me until the technology advances a bit. No convergence or maintenance on it. Anyway, just look around. And use the Search Engine too. Just type in the appropriate search words like "RCA LCOS" and make sure in the little window that you're searching the Hardware Forum. Good luck. Cheers. Don.

[This message has been edited by M.Hat (edited 09-21-2001).]

M.Hat is offline  
post #4 of 4 Old 09-22-2001, 11:37 AM
AVS Forum Special Member
Join Date: Jun 2001
Posts: 2,650
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 69 Post(s)
Liked: 29
I could be wrong, but regarding maintenance, it seems apparent that the delivery "crews" for an awfully lot of CRT RPTV's are arriving at consumer doorstep really screwed up! They are either damaged beyond repair, or require major surgery. I am just wondering if these 50"+ units are just too big and sensitive to realistically be delivered without damage???
WOLVERNOLE is offline  
Sponsored Links
Closed Thread Local HDTV Info and Reception

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off