Wednesday, September 16, 2009

Project 1 - CRT TV Set - Day 1

Finally the journey begins...

I would like to precede this post with a warning.  There are several parts inside a CRT Television that are extremely dangerous to touch, if they still contain an electrical charge.  This does not mean just unplug them.  Proper methods should be taken to insure that the parts are discharged of any electricity stored within them.  A good guide on doing this is contained here:  How to Safely Discharge a CRT TV
Be sure to perform this action once the TV is open, and we have access to the CRT anode lead.  Also, be careful with the actual CRT, as this is a vacuum and could implode if broken.  Eye protection is encouraged.

Now that we have the formalities out of the way, lets begin with a nice view of the project.

This TV, like many electronics you will see in future posts on this site, has led a long and healthy life.  Unfortunately for it, I support the complete euthanization of electronics who can challenge me in age.  Now, at first glance, a TV doesn't appear that special.  It have a big glass screen, a plastic covering, and some plugs on the back.  To reveal the true glory of the TV, we must first strip it of its covering.  After a simple removal of a few screws on the back with my trusty screwdriver, the back panel lifted quite easily off of the rest of the TV.  This left my TV nicely exposed to the goldmine of parts it concealed.

Suddenly the TV becomes exponentially more complex.  Now, we can proceed witht he directions at the beginning of this thread.  The first thing to disconnect is the Anode Lead, which looks like a suction cup attached at the top of the TV.  Simply follow the instructions from the guide, sliding the screwdriver underneath the cup and prying it loose from the TV.
Now that the Anode Lead is disconnected from our CRT, we need to remove the CRT board, which is resting on the back of the CRT Monitor.  It should be pretty easy to identify as the green board that looks out of place, sitting up in the air by itself.  It should be fairly easy to unplug from the monitor, with its one round white connection.  After it is removed, then the actual TV Board needs to be removed.  This is the larger circuit board that is actually down in the TV.  It will most like require the removal of a few screws to pull it out.  This should give you the capability to remove most of the components from the actual TV Housing.
Even though we have extracted all of these parts from the case, they still have alot of wires running off of them, making it very difficult to maneuver either of the boards.  Follow each of these connections, and you should be able to disconnect all of the wires attaching the board to the TV.  Now the only component remaining in the TV, will probably be speakers screwed into the case.  Remove the screws and remove the speakers.  Now put the back of the case back onto the front and screw it back closed.  This will help protect the CRT from being broken, causing health hazard and an annoying glass mess all over your room or workshop.
You should also be able to remove the connections between the CRT Board and the TV board, leaving a naked CRT Board.  The best value for these is if left completely in-tact, although if you really want to remove the few components on the board you are welcome to. 
If we look at the CRT Board as a town, then we are moving in to the big city.  The TV Board is full of enough parts, that it may appear overwhelming at first glance.  To simplify the process, we will remove large bulky parts first, and clear up alot of space at the same time.  One part, we have already dealt with moderately.  The Flyback transformer is on the other end of that suction cup we removed from the CRT.  It should be a fairly large black object with red cables coming from it.  Mine was located on one of the corners of the board.
This is possibly the most valuable part of the entire TV.  It is also extremely useful in many of the DIY projects available on the internet, particularly dealing with High Voltage projects (It can also be extremely dangerous when charged with electricity. Use extreme caution when using the Flyback Transformer in any projects).  On closer examination you will find it is attached to the board by a ring of metal leads soldered in place.
One thing of note on my board is that the leads are labeled.  This is very useful later on for testing the Flyback Transformer, although not all boards will have these convenient tags.  If your board has them, be sure to document them somehow.  Now it is time to begin use of the soldering iron.  Heat each point, removing the solder with a solder sucker.  After all points are clean of solder, the Flyback Transformer should pull out of the board quite easily.  If it is sticking, determine whether you need to clean a point a little better, or if you just need to be a little rougher with pulling it out.  Once free,you can set it aside for whatever purposed you have planned for it.
Two other pieces of note are directly related to watching your TV.  One is the coaxial input for the TV, and the other is the Tuner located inside the TV.  The coaxial input should be directly connected to the Tuner, so it should be fairly simple to find.  The coaxial input will probably be attached to the board with just a screw or two.  The Tuner, on the other hand, will be soldered on the board like the Flyback Transformer.  Simply find the solder leads and remove the Tuner in the same method.
Unfortunately, that is all I have time to work on tonight.  Next time, we will resume work on the TV, and go deeper into the TV Board.  There is still alot of interesting, valuable, and useful parts to be found and removed.
Until next time,
Fletch

3 comments:

  1. you may want to get warning on the flyback transformer

    ReplyDelete
  2. I'll add that in. Thanks for the tip.

    ReplyDelete

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