TV repairable?

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Hi all: My 15-yr old Toshiba 27" crt television has recently developed a problem which is that approx 15 minutes after being turned on, the picture bows inward on the left and right sides. Then, after a few more minutes, the picture resolves and returns to normal and remains perfect for the remaining time the tv is on. If the symptom described above means the crt is wearing out, so be it, the set will soon be history. However, I'm wondering whether some other, replaceable part, might be going bad and causing the temporarily distorted picture.
Would appreciate any suggestions re. probable cause(s) of symptom described above. Am basically novice, but handy and with soldering skills, and have done a few simple tv repairs in the past. Thanks for your replies!
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See if the problem can be influenced by vibration. Smack the set on it's side to see if you can influence it. If so turn the lights out and look inside the vents. See if you can see small sparks that could be a bad solder joint. Because the problem comes and goes it may very well be a bad solder joint or connection. Be safe. If you don't know of the dangers involved then stay away from the repair.
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Bowing in of the sides of the picture has nothing to do with the crt , it is the deflection yoke (coils) at the base of the tube that move the beam from one side to the other and top to bottom. Have you tried running the set with the back loose enough to greatly lower the internal temperature, and see what effect that has.
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On 01/16/2011 10:05 PM, hr(bob) snipped-for-privacy@att.net wrote:

The real answer, sadly (it offends me to say this) that it's likely not *worth* repairing, as you can likely get an equivalent size widescreen 1080i flat screen that won't require a DTV converter box for $300 or less.
nate
--
replace "roosters" with "cox" to reply.
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wrote:

Yes, but don't give the impression that replacing the yoke will solve this, because he might go do it, even though yokes are expensive. I think it more likely it is the circuit that powers the yoke.

Maybe, but this is a "repair" group. Some of us live to repair.
STill, what I would do at my stage is nothing, and figure a few minutes of distorted picture is nothing, and I'd watch it the way it is until it got intolerably worse, or I got a free tv somewhere.
When I was eager to repair tvs, I might have tried looking for swollen nd broken capactitrs, or signs of burned parts, but otoh by 15 years ago, everything may have been in an integrated circuit.
OP, whatever you do rememeber that the picture tube holds thousands of volts, even after the set is turned off and unplugged. The picture tube is one big capacitor. I've always deeply avoided the thick red wire that goes to the picture tube, and I've always avoided the whole surface of the picture tube also. Especially if it is dust covered. Maybe dust conducts elecricity, for all I know. (It has 15 to 20 thousand volts when running, maybe more for a picture tube as big as yours.)
The yoke also has a couple thousand volts on some leads, but only when the tv is on IIUC. YOu can always use a voltmeter to check on that, but not so much the picture tube, whose voltage tends to be hidden under a big rubber wafer at one the picture tube end. There used to be a metal cage at the other end, for the tech's safety, but those went away 20 or 30? years ago to save weight. It's also hard without a lot of experience, more than I have, to fix these things without a schematic, and they are about 30 dollars last I looked, years ago.
It stinks, doesn't it?

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Yeah, it's only *worth* repairing if that's what gets you off, but then you become that weird TV guy whose house is stacked with old sets awaiting repair, and your hair is sticking straight out from one too many encounters with the high-voltage on the CRT.
The state of affairs is such that the low failure rate and low cost to manufacture "durable" goods these days, that it's cheaper to replace the few that fail with new units than it is to staff and stock a repair facility.
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On Mon, 17 Jan 2011 13:05:08 -0800 (PST), snipped-for-privacy@rochester.rr.com wrote:

That would be me. Once in college I ended up with an electric percolator, but only the main piece. By the time I bought the pipe in the middle and the basket and its lid, and maybe the pot's lid and glass middle, and the cord, it cost more than a new coffee pot, even in 1967
I wouldn't do exactly that again, but I've never regretted it. And I don't even drink coffee.

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Since a little after vacuum tubes went out, there's not much you can do unless you have some electronics skills or want to learn them. Back in 1980 a buddy gave me my first color TV, but it had no color. There was a repair shop and I took it there after the mechanical tuner screwed up. That guy fixed the tuner and replaced the "color chip" for $75. Good deal, since a TV like that was about $300. Now you can a much better CRT TV for $50-100 at a thrift shop. I've got a perfectly working 27" Magnavox in one room my wife paid $30 bucks for, and a 30" Bell-Howell in another room that my son picked up for $100 at a place called Cash Converters around here. Not a pawn shop, but you they'll pay for used working electronics and other crap. Add $10 for a universal remote and you're set. I've got perfectly good 18" and 21" CRT monitors that I paid good money for sitting idle because I got flat screen replacements as gifts. Kinda pissed me off but I couldn't say anything. Wouldn't look right. Waste of money to me. Probably be a waste of money for you to get that fixed. I've got a 27" CRT TV in my bedroom that I was sure needed replacement about a year ago when it would go blank. Smacked it a few times and it hasn't acted up in months.
--Vic
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?

If you can find the problem and repair it yourself, it may be worth it. If you have to pay for repair, it is not worth investing much in a 15 year old set. There are some amazing prices on 42" sets now and the picture quality for HD is a huge step up.
When my old CRT got fried after a power surge, I was happy to buy a new set. After 6 months, I'm still amazed at the picture quality with HD.
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besides a brand new LCD tv of the same size will save lots of electric. the savings on your electric bill might just pay for the replacement over a few years.
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Ed Pawlowski wrote:

I'm with you. Santa got me a 37" LED/LCD and it didn't cost much more than $500. Wattage on the 27" old tv, 180 Watts; new tv, 56 Watts.

If only I could remember the HD channel numbers that carry my usual channels. Getting there.
nancy
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On 1/16/2011 9:18 PM, PE wrote:

I'll bet it is a bad capacitor, fixed hundreds of video game monitors with similar symptoms. Most of the time we don't even test the caps, look for parts of the circuit board that look like they run hot, then replace all caps in that area. Also replace all caps rated for 100 volts or higher, they go bad much more often. Also if you know your way around a monitor, be sure to change the caps in the vertical and horizontal circuitry. For newbies in the video game monitor repairs, lot's of people put together a list of all the common caps that fail on that particular model and sell you a bag of caps and a picture showing what goes where. The "cap kits" will fix several problems at once, including problems you didn't notice yet but are about to go.
Actually my TV is doing the same as yours but it stays that way. When it quits I'll probably take a look inside, but chances are I'll toss it and get a new one instead of fixing mine. TV's have a lot more components than cheap video game monitors and aren't as easy to fix (not for me anyway).
OH, no way is that a sign of a bad CRT, and no way is the yoke itself bad, just the circuitry that powers the yoke.
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On 1/16/2011 10:25 PM, Tony Miklos wrote:

You beat me to the bad capacitors. 15 years is a darn good life for consumer grade electrolytic capacitors. I had a customer who's Viewsonic LCD monitor on his server/office computer died after a year. I thought it a shame to toss a nice monitor so a little Google search turned up a common problem with an electrolytic in the power circuit on the main circuit board. The store had a problem with recurring power surges and even though there is good surge protection on the computer system, what can get past the surge arresters will damage some components. I believe it was a 100uf 16volt electrolytic and when looking at the circuit board I noticed lands on the board for a parallel capacitor. I installed two 47uf 35volt caps and there have been no more problems with the monitor.
TDD
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On 1/17/2011 5:06 AM, The Daring Dufas wrote:

Google might work. I fixed a couple of DTV converter boxes by googling the problem and found a cap that failed in all of them. Likewise replacing caps is a common problem in switching supplies (Mac supplies in particular) although that is not the issue here. Claire is close to having this nailed, the symptoms are almost classic.
Capacitors have gotten a lot smaller for the same ratings, I suppose it's not to be unexpected that they would fail more often. The digital stuff in particular as switching supplies are hard on them.
Not sure how long modern HV sections hold a charge, but some caution should be exercised.
Jeff
The store had a problem with recurring power

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On 1/17/2011 7:46 AM, Jeff Thies wrote:

I just reread his post and I've seen the same symptoms caused by cold solder joints. After a warm up the device starts working correctly but it will GRONK if you jar or slap it hard. I used to repair a lot of two way radio gear and when I finished repairing a problem, I would smack the unit against my carpet covered work bench much to the consternation of the other techs in the shop. I explained to them that the radio was going to get a lot rougher treatment in the field. I've also seen a lot of very strange thermal intermittent malfunctions.
TDD
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On 1/17/2011 9:18 AM, The Daring Dufas wrote:

It's the bowing part that lead me to think cap, but you are right that healing like that is not really a cap thing. I've got a friend who still fixes TVs, though mostly it's all flat panel stuff now. I'll ask if I get a chance...
After a warm up the device starts working correctly but

It's better to know sooner than later. Toward the end of my repair "career" I was mostly fixing giant car amps. Nothing I could do to them could come close to the abuse they would get later! Oh, the abuse!
I've also seen a lot

I've used more than my share of freon tracking them down. Or not tracking them down!
Jeff

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On 1/17/2011 5:05 PM, Jeff Thies wrote:

I got a call a little while ago from the customer who had the Viewsonic monitor quit because of a bad electrolytic, an identical monitor on another workstation just did the same thing. I have to pick it up today and repair it.
TDD
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The Daring Dufas wrote:

Hmmm, Repair? In our town we get an 18 inch monitor for 79.00 on sale. What is your hourly rate? Mine is 250.00 plus T&L minimum 2 hours. My hobby is fixing tube gears specially guitar amps for poor local musicians. No chaege for them. Just I let them buy necessary parts.
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On 1/17/2011 6:55 PM, Tony Hwang wrote:

Good for you. But, you wouldn't have many customers fixing consumer electronics at that price.
For a reasonable price, putting a Viewsonic Flat Panel back in service is worth it. Neither is it junk, nor is it worth sinking $500 in.
Myself, I don't have to charge $250/hr to feel like I have self worth. Just how big is your hwang, Tony?
Jeff
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Jeff Thies wrote:

Hi, I am in large scale comm. system support. Worldwide there are ~100 of them. I am officially retired. Still they bug me when in big trouble.
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