OK, OK, time for me to step in. 20 some odd years ago, I repaired TVs for pocket money whilst in high school. In my junior & senior year I took Radio & TV repair at vocational school (where they sent folks not deemed suitable for college). After high school, I went on to earn a BS in electrical engineering I think I have some credentials for issuing an opinion on this subject.
Cathode ray tubes (CRTs) require an operating voltage in the 30K volt range. Furthermore, the physical structure of a CRT acts as a capacitor which will retain this 30KV charge even after the monitor is turned off. Depending on the leakage current, this charge can last for a long time (months). Now 30KV sounds like a lot of juice, but you have to understand that it is current, and the length of time the current is applied that kills you, not voltage. A CRT acts as a capacitor, but a very small one. If a CRT discharges through you, current flows only for a *very* short time - not enough time to do any damage. It is exactly the same as walking across a carpeted floor with rubber sole shoes in the winter and seeing a nice fat blue spark jump from your finger to a doorknob. The very small capacitor (you) was charged (by walking across the carpet) and then discharged to ground (the doorknob). Even though you can build a 10KV charge this way, the current that flowed as a result does not kill you, or even burn you. So, you are not going to be killed or burned by monkeying around with an *unplugged* monitor. You may receive a nasty shock, but no lasting damage, unless you happen to snag your rapidly retreating arm on a bit of metal framework and rip a nice gash (don't ask...) With that said, there is just about zero chance you will be able to fix anything once inside. Most monitor problems are either power supply or flyback circuit related - both of which are complicated animals and would probably require factory literature to troubleshoot and repair. Even if you could isolate the failed parts, buying replacements would likely prove impossible. If you want to open it up and look for something obvious, go ahead (but, please, with the monitor unplugged). You can discharge the CRT by: 1. take a 2' piece of wire 2. strip a couple of inches of insulation off each end 3. wrap one bare end of the wire securely to some of the monitor's metal framework (i.e. ground) 4. wrap the other bare end tightly around the shaft of a long, skinny flat-blade screwdriver. 5. Slide the end of the screwdriver slowly under the rubber boot on the CRT where the high voltage wire connects. Continue sliding the tip toward the center of the boot until the tip touches the metal clip in the center of the boot. Don't be alarmed by the loud crack that happens. Please, please, please keep in mind that all this applies to an unplugged monitor. A plugged in monitor with the back off could easily be lethal! Also, keep in mind that a CRT is a glass bell evacuated to a high vacuum. While they are not extremely fragile, they should be treated with respect. They can send glass flying if ruptured. Lastly, one thing to think about. If you find a simple problem and fix it, is your unskilled repair going to turn your monitor into a fire hazard? -----Original Message----- From: Ken Davis [mailto:[EMAIL PROTECTED]] Sent: Thursday, January 03, 2002 11:54 AM To: Exchange Discussions Subject: RE: fix monitor Well, Depends on the User. I know how to discharge the capacitor in a safe manner, and which Pots to tweak. But would I recommend someone on this list Doing it not knowing their technically ability? No. Someone might be one Hell of a Mail engineer, but be all thumbs when it comes to this type of thing. And The Flyback should scare you. Unless of course, Getting shocked by a few thousand volts and maybe having to take a ride in the back of an ambulance sound like a good time to you. I've worked on CRTS for a few years. And even though I know what I am doing with them, I am still Scared of what they can do. P.S. Unplugging the thing for a few minutes does nothing to discharge the Capacitor. -----Original Message----- From: Dillon, Jeff [mailto:[EMAIL PROTECTED]] Sent: Thursday, January 03, 2002 11:47 AM To: Exchange Discussions Subject: RE: fix monitor If you have a zero budget or zero boss, don't let the 'ole flyback "capacitor" scare you away. There are lotsa useful pots in there that can fix the focus, the brightness, etc, and you can futz with the magnets if the screen is lumpy. Likewise, many a monitor has been resurrected by replacing a $.25 fuse or the smelly burnt component smoldering on the board. Unplug the thing for a few minutes (an hour if you're paranoid--"years" won't be necessary), use insulated tools, and borrow some rubber gloves if your hair is already spiked. I do agree that it is rarely worth paying for this, so dive in.... -----Original Message----- From: Ken Davis [mailto:[EMAIL PROTECTED]] Sent: Thursday, January 03, 2002 11:15 AM To: Exchange Discussions Subject: RE: fix monitor I realize I am late to this discussion, as I have read many catapult references, however I don't think it was addressed. I am relatively new To the Exchange World, only a year and a half working with it. But I have Been involved with Networking and Computers in general for the last 12 years. I got my start (as probably did everyone here) working on hardware. Richard, I can tell you there are most certainly no user serviceable parts In a monitor. And Opening one up can be Fatal. The Flyback Capacitor Can hold a charge of several thousand volts for years. There is more than enough Voltage there to severely burn you, if not kill you. Like everyone one else Here has said, it's cheaper to buy a new one, then get an old one fixed..... Unless.....You live near a High School that has a Vocational Education Program that specializes in Electronics. These kinds of schools Will usually Fix the equipment at no charge save for parts. Just An idea. Ken Kenneth Davis IT Manager American Wood Moulding, LLC "For a moment, nothing happened. Then, after a second or so, nothing continued to happen." -----Original Message----- From: Tener, Richard [mailto:[EMAIL PROTECTED]] Sent: Wednesday, January 02, 2002 10:58 PM To: Exchange Discussions Subject: fix monitor for all u hardware/monitor geniuses out there do u know a good place on the web to tell me how to open/fix a monitor? _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Archives: http://www.swynk.com/sitesearch/search.asp To unsubscribe: mailto:[EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED] _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Archives: http://www.swynk.com/sitesearch/search.asp To unsubscribe: mailto:[EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED] _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Archives: http://www.swynk.com/sitesearch/search.asp To unsubscribe: mailto:[EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED] _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Archives: http://www.swynk.com/sitesearch/search.asp To unsubscribe: mailto:[EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED] _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Archives: http://www.swynk.com/sitesearch/search.asp To unsubscribe: mailto:[EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED]
