Deconstructing a Rear Projector Tv

[vortish]

I found someone giving away a rear projection tv for free. I snapped that up. So far I have just removed one main power board and one of the lens assemblies. It is surprising little in the way of actual electronics in these tvs. I will take some pictures later on when I dissemble it some more. I got tired and quit for today


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[Jimmymcjimthejim]

Score! There are tons of goodies inside of RPTV's. Among them are the projection lenses, the fresnel lens, the giant front surface mirror (I can't tell you how many times I've scared myself looking into the mirror not realizing that it was a mirror), various electronic components, and even some speakers. Taking apart a RPTV was definitely one of my favorite things to take apart. (I made my own thread a few years back!)

Have fun and stay safe with the capacitors!

 

[vortish]

Score! There are tons of goodies inside of RPTV's. Among them are the projection lenses, the fresnel lens, the giant front surface mirror (I can't tell you how many times I've scared myself looking into the mirror not realizing that it was a mirror), various electronic components, and even some speakers. Taking apart a RPTV was definitely one of my favorite things to take apart. (I made my own thread a few years back!)

Have fun and stay safe with the capacitors!

thanks jimmymc I am having fun taking it apart I also think there is photomultiplier tubes in this one it is a toshiba

 

[Trendkilla254]

Yeah I took one apart myself, mine actually didn't have a front surface mirror in it, it was a normal mirror. I was very surprised to see that.

 

[Deleted member 16589]

Yeah I took one apart myself, mine actually didn't have a front surface mirror in it, it was a normal mirror. I was very surprised to see that.

Mine Had a first surface but the Fresnel Lens was crap some are better than others Mine is Huge but wont focus dow enough to burn Get really hot but that's it.

I was disappointing that all the optics in mine were acrylic.

I already told you this on Skype but just to restate for others between the CRT and optics on mine was filled with mineral oil Got it all over the patio so be careful.

Are the RGB filters in your any good The blue and green on mine had dissolved into the oil

 

[paul1598419]

Keep in mind that the coolant used between the CRT lenses and the CRT is poisonous and you need to use extra care when draining it off. It is an ethylene glycol or similar liquid. You really don't want to get it on your skin and especially don't want to ingest any.

 

[Benm]

Ehtylene glycol doesnt seem too bad though. It's basically antifreeze, the stuff you'll put in your windshield wiper liquid if you live in climates where it freezes sometimes.

By no means go a ahead and drink the stuff, but if you get some on your hands just wash it off under a tap - your hand will not fall off, and normally there should not be a mark on it.

 

[BowtieGuy]

I had a large front surface mirror from an RPTV given to me by a member (starlight); it was 28" x 29" in size. I had it cut into 4 rectangular pieces similar to what brucemir uses.
I'm going to have to mount it to some hardboard, or plywood to make it more rigid since it is quite thin and is fragile in large sizes.

 

[paul1598419]

The stuff they use for coolant in these are a pure form of antifreeze and it states on the container to not let it contact your skin. The stuff you get for your car is diluted and not nearly as dangerous. It is also optical grade and may have other compounds in it.

 

[Benm]

Ethylene glycol is exactly that, one single compound.

As antifreeze you can get it either pure or pre-mixed. The latter is a roughly 50/50 solution in water that you can dump straightly into your windshield washer reservoir. The pure stuff is also sold and recommends you add an equal part of water. In addition to the ethylene glycol the stuff for cars usually has some detergent mixed in as well, but that makes it more dangerous from a toxicological point of view.

Perhaps they do add something dangerous in the TV coolant, but it's surely not the ethylene glycol itself that will harm you.

 

[paul1598419]

I can't say for sure it is ethylene glycol, but pure EG is toxic at a level of 0.1 ml/ Kg. So, it is not a harmless substance. It causes kidney damage and liver failure. I'm sure it won't cause your hand to fall off, though.

 

[SyKo]

Frensel lens in these can be quite fun, lots of burning done during aussie summers.

when i first took one apart i was rather young and the 3 projectors (RGB CRT's) needed re aligning so i tried to turn it into a floor to ceiling projector, curiosity got the better of me and i removed the cap for the color filter for one of the CRT's and liquid ( i think it was coolant?) spilled over every piece of electronics in the thing.
and i had to quickly relocate the TV outdoors permanently.

My advice, dont remove the caps

 

[Trendkilla254]

The coating on my filters also deteriorated. I wasn't going to keep them anyway. Did you take the whole lens assembly apart though? I had 3 acrylic lenses and 1 glass lens in each housing times 3 housings. I don't have a laser powerful enough to warrant trying to make something with it just yet.

 

[paul1598419]

Frensel lens in these can be quite fun, lots of burning done during aussie summers.

when i first took one apart i was rather young and the 3 projectors (RGB CRT's) needed re aligning so i tried to turn it into a floor to ceiling projector, curiosity got the better of me and i removed the cap for the color filter for one of the CRT's and liquid ( i think it was coolant?) spilled over every piece of electronics in the thing.
and i had to quickly relocate the TV outdoors permanently.

My advice, dont remove the caps

Yeah, I've seen this happen before. The correct way to do it is to remove the CTR and lenses together after discharging the CRTs and laying them out, lens down, on a piece of carpet. Then you place the CRT in the lens up position and carefully take it off. There is a rubber gasket inside and the coolant is usually off color and full of particles if it has been used for a long time.

 

[Benm]

I can't say for sure it is ethylene glycol, but pure EG is toxic at a level of 0.1 ml/ Kg. So, it is not a harmless substance. It causes kidney damage and liver failure. I'm sure it won't cause your hand to fall off, though.

Just checking on that, the -lowest- lethal dose to humans known is 0.8 grams/kg, equating to ingesting something like 50 grams off the stuff. This can happen when kids drink it because of its sweet taste, but there is no way you'd ingest that much my taking apart any device even if you licked your fingers while doing so.

As a reality check i tend to compare lethal doses to those of commonly used substance such as table salt, which kills about 50% of mammals at a 3g/kg intake.

There is no known lowest-fatal-dose for table salt as it's effects are usually chronic, not acute. Then again if you shared a kilogram package of salt (commonly sold) equally with 4 people, chances are 2 of them would die from that (and the other 2 ending up in hospital for a while).

Ethylene glycol is realiscally as poisonous as ethanol is. Ingesting a shot glass off it will probably do you little harm, but if you down a liter of the stuff the outcome is probably bad. Try drinking a liter of vodka or whiskey and the outcome of that is also not that good, and that's only a 40% solution in water

 

[BowtieGuy]

Remember to be very careful with ethylene glycol if you have pets! It doesn't take nearly as much to be fatal for our dogs and cats, and they love the sweet taste of it.
Many animals are poisoned every year, by ingesting anti freeze, sometimes accidently, and other times purposely.