Getting rid of a CRT. Anything worth keeping?

Started by boogietone, September 14, 2013, 09:13:30 PM

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boogietone

I have an old, working Viewsonic 17" that Goodwill won't take. Is there anything worth taking the time to cannibalize before sending to the dump?
An oxymoron - clean transistor boost.

pappasmurfsharem

Quote from: boogietone on September 14, 2013, 09:13:30 PM
I have an old, working Viewsonic 17" that Goodwill won't take. Is there anything worth taking the time to cannibalize before sending to the dump?

Probably dangerous to disassemble. I wouldn't recommend it. CRTs can explode
"I want to build a delay, but I don't have the time."

haveyouseenhim

If you have any experience with high voltage save the flyback transformer and make a plasma speaker.   Seriously, if you don't have experience with high voltage, don't bother.
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I'm sorry sir, we only have the regular ohms.

boogietone

I am aware of the high voltage issue. The thing has not been plugged in in years.
An oxymoron - clean transistor boost.

pappasmurfsharem

Quote from: boogietone on September 14, 2013, 09:23:57 PM
I am aware of the high voltage issue. The thing has not been plugged in in years.

Crts can still explode due to pressure.
"I want to build a delay, but I don't have the time."

J0K3RX

#5
If anything they will implode.. it is highly unlikely that a monitor would explode. CRT's are very thick and are usually imploded by something hitting them. That being said I have broken quite a few of them with rocks, hammers, dropping them face down etc and they are very disappointing as far as explosions go!  However, the CRT can hold a charge for quite some time especially if it was been powered on recently. To discharge the tube you have to Run/twist a wire around the shaft of the screw driver and run it to ground. Slide a flat head screw driver under the rubber flyback/anode plunger on the top of the CRT until you hit the 2 metal prongs. You should hear a pop or see a spark if there is a charge and you discharge it. You really should ALWAYS do this as a precautionary measure, I have seen these hold a charge for months just sitting on the shelf and not being powered up! A charged CRT carries high voltage, about 25,000 to 27,000 volts in a color unit!!! NEVER use both hands when working on these! The shock will go right in one arm and out your other arm passing right through you heart and you won't be able to let go if it is powered on!!! It can KILL you or cause secondary injury from you pulling your arm back wildly from the shock and you could slice your arm or hand on something etc...! After you have discharged the CRT you then should discharge any caps on the boards! The caps can also hold a charge for a long time (DON'T TRUST bleeder resistors!)... You can use the same tool you used to discharge the CRT by carefully turning over the circuit board/s and run the screw driver tip across both leads of all of the high voltage caps. I usually bridge them out from the + to the - side of each cap with the screw driver. I have had some caps arc out and actually weld into the end of the screw driver. I have carelessly picked up boards before not knowing the caps were still charged and touched across the leads, believe me I don't forget anymore to discharge them first!!  After doing those simple steps there are many usable parts inside, have at it!



Doesn't matter what you did to get it... If it sounds good, then it is good!

thelonious

Quote from: boogietone on September 14, 2013, 09:13:30 PM
anything worth taking the time to cannibalize before sending to the dump?

Heat sinks, headers and wire, lots of components. I snagged a bunch of BC548s and 558s, various caps and diodes, 5W resistors, etc.

J0K3RX

Quote from: haveyouseenhim on September 14, 2013, 09:20:57 PM
If you have any experience with high voltage save the flyback transformer and make a plasma speaker.


Or, you could build a Jacobs Ladder :icon_mrgreen: I have made a few... don't know why, it just intrigued me.. :icon_rolleyes:

Doesn't matter what you did to get it... If it sounds good, then it is good!

J0K3RX

Quote from: thelonious on September 15, 2013, 01:18:07 AM
Quote from: boogietone on September 14, 2013, 09:13:30 PM
anything worth taking the time to cannibalize before sending to the dump?

Heat sinks, headers and wire, lots of components. I snagged a bunch of BC548s and 558s, various caps and diodes, 5W resistors, etc.

Usually a few nice heavy inductor coils in there also... If anybody is building the GTFO these might work well?
Doesn't matter what you did to get it... If it sounds good, then it is good!

duck_arse

you must chew through a lot of screwdrivers, jok3rx.
You hold the small basket while I strain the gnat.

boogietone

Thanks everyone for the replies (and the safety tips, though I am aware of the issues). I have always wanted a plasma speaker. So, we'll give that one a go.
An oxymoron - clean transistor boost.