Taking the case off a television.

[DreamWeb]

Hey folks!

I'm now building my Cabinet now.. and I'm thinking about putting a television in instead of an arcade monitor to help save money.  I'm one of those guys that just wouldn't notice (or care) for the increase in quality that a real arcade monitor would provide.

With that said..  My cabinet is exactly 25 3/4" wide.  So, I'm considering a 27" television.  Obviously it wouldn't fit unless I took it out of it's plastic casing.

what I'm wondering is... how dangerous is this?  How easy is it to do?  How hard is the mounting if it's out of it's case?

Would I be better off just finding a smaller TV that would fit in with the case on?  I'd really like to maximize the size.. 

Thanks guys!

David

[D_Zoot]

Once you get the back off the TV,  discharge the tube.  That should address any safety concerns.  Search this forum for discharging tubes, there have been some excellent posts on the subject.

The problem with de-casing a TV is that often the case is also the frame for the tube and chassis.  Once you get the case off, there won't be any way to mount anything without some fabrication.    You'll have to pull the back off to inspect the thing inside and see what you are dealing with.


Regards,
D
 

[DreamWeb]

Ok, after reading some previous posts on de-casing..  I'm thinking it's not such a hot idea.

Now I'm wondering if I can keep the case on the television... but saw off the sides (which are mostly speaker anyhow (I won't even be using the speakers)  Should the TV still operate fine if the speakers have been sawed off?

I'm thinking of this television.

http://www.jvc.com/product.jsp?modelId=MODL026901&pathId=73&page=2&archive=true

Has anyone tried something like this before?

d.

[D_Zoot]

Assuming there is clearance inside the set to do that,  I would wonder if that would effect the stuctural integrity of the case.   Since it's simply a plastic box, cutting the sides off may weaken the case to the point where it doesn't hold the set together.....    Food for thought...


D

[ericball]

The first step to decase a TV is to unplug it!  Then open it up to get a feel for how easy it will be to take apart in the first place.  You're looking for screws and hoping it comes apart into two pieces.  One TV I tried to take apart had lots of stuff connected to the back and I couldn't see any way to easily re-attach and put everything back together.

Okay, assuming you have the back off have a look inside at the corners of the tube.  You will probably see some "ears" screwed into the front bezel.  That's all that typically holds the tube to the case.  If you decase the monitor, that's what you will use to hold the tube to the cabinet.  If you don't decase the monitor, that's what is holding the tube against gravity.  (So if you are building a cocktail cab and don't decase the monitor, the weight of the tube has to be transferred by the front bezel, through the sides of the case, to the back of the case.  Ugh.)

The next thing to look at is how the rest of the innards are attached to the case and each other.  This is where things may get ugly.  For the TV I decased the PCB  was attached to the bottom of the case in such a way that I couldn't get at it without disconnecting the tube.  The front panel was worse, I ended up attacking it with a drill and hand saw to cut it (and the bottom of the case with the PCB intact) away from the rest of the case.

I did all of this without discharging the tube (or the large caps).  I just made sure I didn't grab those parts.

[ginno]

Dream Web.

Im in the process of mounting my decased TV, i have been stuck on this process for months. :S

This is my experience so far:

Cutting the sides off the TV will probably be a bigger issue then removing it completely.
The only thing that made the case of my Sony Trinitron strong is the fact it forms a bond around all 4 sides of the tube.

[Cuba]

I might be able to help if you want to go the decased route.  I did it with a 27 inch tv on my second arcade.  Definitely not easy, but it was the only way to make it fit inside the cabinet. It was this machine here.
http://home.comcast.net/~communistcuba/capcom.html
There arent any pictures of the mounting process, but I can take a few of the brace if youd like.  If you do go this route, there are some things you must know, so Ill try to mention the most important things.

1-Safety. Learn how to discharge a picture tube. If you dont want to learn, then leave it unplugged for a couple days before you do anything.

2-Take pictures of the wiring. All tvs have cabling going from the back of the tube to the circuit control board.  If you unplug the wire and dont remember where they go, your screwed.

3-Purity controls.  On the back of the picture tube will be a set of magnetic rings. They are the fine tunning adjustments for the picture. DO NOT TOUCH THEM. I completely messed up a tube cause I didnt know what they were and once moved I didnt know how to set them back.

That covers the "how not to mess stuff up" part.

Alright, dissasembly. I began by placing some folded towels on the ground and place the tv face down on them.I removed the case screws and took off the back.  Then I examined the wiring and took pictures of the way it was hooked up.  At this point I discharged the tube just to be sure, and then I began unhooking the wiring.  At the back of the tube will be a circuit board, this pulls straight off. The Anode is the black plug on top of the tube with a thick wire. Thats the dangerous part that needs to be discharged before working on it.  Once discharged, it can be removed by unclipping it.  With everything else unhooked, the control board can be removed and put aside.  You should be left with only the picture tube inside the plastic case.  This is held in by 4 big screws, one in each corner,  Removing these will free the tube.

If youve gotten this far, then this is the part to care about: mounting it in a cabinet.

Things to remember: 
1- The tube is extremely heavy so whatever brace you build must be extremely strong. 
2- The wiring between the control board and the tube is usually short, so once the tube is mounted you might have to build some kind of shelf to hold the control board. 
3- You might have to solder wirings to the "on switch" on the control board in order to turn on the tv from a convienient place.

Alright, with the picture tube now lying face down by itself, its time to design the frame to mount it in.  I decided to use a combination of heavy steel "L" brackets and wood beams (1.5 in x 1.5 in x 28 in).  Originally I thought I could just mount the brackets in the case, but it was way too hard to get the spacing right. So here is what i did.
I cut 2 wood beams the exact width of the inside of the cabinet.  One would be for the bottom and one for the top of the tube.  Then I mounted the L brackets to the beams, so that they also touched the walls of the cabinet.  With that built, I lined it up with the tube, and started cutting the L brackets so they matched up with the mounting holes of the tube. Its hard to describe in words, so I did a real quick paintshop picture.


The center of the tube would rest on the beam, and the mounting holes would line up with the L brackets.  Once I had the two mounts perfected, I screwed them into the cabinet and the  tube matched up perfectly.

Honestly it was a big pain in the ass,  but it came out nice in the end.  If you want any more details, just ask.

[JoeB]

There's one other thing that is ***ULTRA*** important when working with TV's:

Don't forget to put an isolating transformer between the AC plug and the TV power!  Normally, the chasis of a TV is hot!  This is normal because the case protects you (and cases are made from pastic).  But if you remove the case, and screw the TV into your cabinet, you'll make your entire cabinet hot!!!

The iso transformer will protect you from that.

[ginno]

Hi guys i dont want to divert this topic from DreamWebs original question but i just thought i'd post a few pics of the frame i am looking to use.

This is the SONY trinitron tv i am using



This is the frame i have tacked together (still have to complete welds before joining it to the TV)



Basically the frame will just support the TV to sit upright with the bottom of the frame bound to a monitor shelf in my cabinet.

The points on the TV and frame circled in red are the points where the 2 will be joined.

The circuit board will sit behind the back of the TV, im still not sure how i am going to mount the plastic casing its in to the metal brace on the back of the frame.

Joe B, i will have to use the isolating transformer you talk of because of the metal contact the frame will have with the TV right?

Does anyone have any comments on my solution? (will it work?)

DreamWeb maybe this frame could be an option for you? Have you decided on what your doing yet?

Cheers ginno...

[AndyWarne]

About isolating transformers: Most modern TVs don't need them and no longer have live chassis.
If the TV has no outside-world connections such as composite in, etc then it just might have a live chassis.
If it does have external connections (other then the antenna) it will not have a live chassis since provision of any external plug is not possible on a live-chassis TV. The plug connections would be live and so would anything connected to them.

[MonitorGuru]

I havn't posted in months, but the discussion in this thread have required me to post.  I've posted the same info in numerous other threads and FAQ's but it seems a lot of DISINFORMATION is still out there. Some of it DEADLY!


1) If you are NOT working (e.g. soldering, diagnosing, replacing components, swapping tubes), you *NEVER NEED TO DISCHARGE A TUBE*. Doing so when you don't need to actually INCREASES the risk of damage to the unit and to safety issues to yourself and surroundings.

It's simple: Do you take apart your TV or computer monitor and discharge the tube every time you move it to the other side of the room?  Nope? Well, you don't need to discharge an arcade monitor or TV removed from it's case either.

The *ONLY* time you should discharge the tube is if there is a REASON you neeed to detach the large red anode wire from the tube.  That is the ONLY TIME YOU MUST DISCHARGE -- period. (e.g. replacing the flyback transformer would require this, replacing the horizontal output transistor might require this, doing a Cap kit, etc..)

If you're working with a set and it's all still complete, it is safer to have the anode wire attached to the tube, because as long as the set is working fine, and you don't stick your finger under the grey attachment cup, the set is keeping the deadly charge in a closed loop with ground on the outside of the tube, netting nothing.  A tube without anode cap on it can actually build up a static charge (though not as much as when it is on of course) since the inside isn't connected to the outside.

Plus every time you discharge you run the risk of:
a) Scratching or breaking the glass around the anode, thus increasing the risk of failure or sparks jumping out from under the cape
b) bending/breaking the anode wire ends
c) sending the discharge though the circuitry it can't handle in the time you zap it
d) zapping yourself attempting to discharge
e) hitting something and breaking the tube, either simply ruining it (letting air in) or causing a dangerous implosion.

Again.. if there is no reason to separate the electronic board (chassis) from the tube, there is NO reason to detach the anode wire from the tube. 

Also, the largest capacitors on the electronic board (chassis) hold quite a charge, regardless if the chassis is attached or detached from the tube--usually when the board itself has blown a fuse. Therefore discharging the tube does nothing to disappate this charge, and you then think you can handle the board without fear, only getting one heck of a shock even with it detached from the tube.  When all together, treat it with respect, only handle the frame/outside of the thick part of the glass and never touch the bottom of the circuit boards and you are safe.


2) NEVER ASSUME A TV DOESN'T NEED ISOLATION.  I have picked up quite recent TV's that indeed require isolation to be worked on or have something connected inside past their inputs. You can never go wrong using an isolation transformer when NOT needed, but you certainly can go wrong assuming one isn't needed when in fact it is.


3) The fact that a TV has or has not any external connectors cannot be used as a basis for judgement as to if it has a live or non-live chassis. Absolutely NOT.  Filter capacitors and Optocouplers are frequently used on live chassis TV's to protect inputs.

For years, many TV's have used simple ceramic capacitors between the antenna, cable and other similar inputs to allow the frequency through but not allow the voltage/amperage (shock) out.  Also some TV's use what are called OPTO couplers that isolate the input from the chassis.  They are basically like a remote control transmitter and a remote control receiver, in a tiny little chip. They use light to send the signal across a gap. Since it's light, no electrical connection exists and therefore the hot chassis cannot get grounded to earth from the external connector.


These points I want to make it clear that seem to always go around due to people being too scared or not done enough research to understand how things are implemented.

[DreamWeb]

Thanks folks for contributing!

I'm sure all this information will be helpful for someone!

I decided to go with a slightly smaller television... that I could keep the case on.

Thanks!

d.

[ginno]

Not sure if anyone is still following this thread, just thought i'd post my progress

Have mounted the TV in the frame and spent the day trying to fit it in the cabinet

Here is some pics of it in the frame






As you can see the main board has been left in its plasic mounting and just zip tied to the back of the frame.