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Crumbtrail TV Forums: TV Equipment: TV Repair Forum:
Need Help

 
 


tremonti04
New User

Jan 26, 2008, 5:42 PM

Post #1 of 12 (1644 views)
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Need Help Can't Post
My 2 year old Insignia TV, is causing me some troubles. The sound works fine but there is no picture except for a very skinny line across the whole TV. any ideas what this could be? I'm basically just trying to find out is it worth fixing or buying a new TV.
Thanks.



cademan
New User


Jan 27, 2008, 12:46 AM

Post #2 of 12 (1637 views)
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Re: [tremonti04] Need Help [In reply to] Can't Post
Your vertical output has collapsed! Since I don't have a schematic of the circuit, it could be a couple of things. 1): vertical output transistor is shot. 2): a winding on the flyback transformer could be shorted. 3): a vertical oscillator coil, and the very worst, 4): picture tube. Other minor problems could be open resistors somewhere in the vertical circuit.


tremonti04
New User

Jan 27, 2008, 3:21 AM

Post #3 of 12 (1629 views)
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Re: [cademan] Need Help [In reply to] Can't Post
Do you think its something worth fixing or just buying a new TV?


cademan
New User


Jan 27, 2008, 6:15 AM

Post #4 of 12 (1626 views)
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Re: [tremonti04] Need Help [In reply to] Can't Post
Most of todays TV's are designed by computer with a lot of cheap parts and cheap labor, but most of the top brand names come with 1 year warranty and may last up to 5 years. 10 if your lucky! With that said, most TV's today are what we consider throw-aways. If your TV needed repair after only 2 years, then I would go with some other brand. As far as repair goes, how much did your TV cost. Did you buy it brand new? How much was a repair shop estimate? Are you willing to put in the time to chase down a schematic? Do you know how to use a volt meter? If you find a schematic, then troubleshooting can be pretty easy and straight forward. Overall, is it worth your time and trouble?


shadetree
Veteran

Jan 27, 2008, 6:50 PM

Post #5 of 12 (1615 views)
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Re: [cademan] Need Help [In reply to] Can't Post
how in the world could it be the picture tube


techchris
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Jan 27, 2008, 11:08 PM

Post #6 of 12 (1610 views)
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Re: [tremonti04] Need Help [In reply to] Can't Post
i think cademan is being rather over enthusiastic about something he or she knows little about. first resolder the pins on the vertical scan ic which is a flat ic mounted on a big heatsink. if that does not cure it then change the ic and check you have about 25-35 volts feeding to the ic. It def. wont be the tube or the flyback transformer


terminator4
User


Jan 28, 2008, 3:50 AM

Post #7 of 12 (1605 views)
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Re: [techchris] Need Help [In reply to] Can't Post
as i said before in another post older tvs in the 1980's were built to last,unlike tvs today where if the parts break like the tv tube, you have to throw it away, most of the parts in tvs now in days is probley unlikly to be repairable


cademan
New User


Jan 29, 2008, 8:29 AM

Post #8 of 12 (1582 views)
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Re: [techchris] Need Help [In reply to] Can't Post
I'm a TV tech from way back but haven't done it for about 20 years now. I actually had a picture tube that was shorted that caused my flyback to develop a short in the windings which developed a white vertical line so the picture tube can be bad, so I had to replace the tube and the flyback. Also check out Robert's Television Repair Manual 1974-1978, a shorted winding in the flyback can also cause a vertical white line. Please understand and be careful not to say hurtful things about people you know nothing about! I was just trying to throw out some basics and add a little help. Most TV's today are computer controlled anyway and I usually won't touch 'em. I'm still watching a 35 year old zenith that I have had to repair 5 times. It's a hybrid (half tube - half transistor) guess I'll be screwed if my flyback or deflection coil goes tits up. I'll just have to leave the 'IC' circuits to the younger generation. Without knowing the guys TV or schematic, I was just trying to be a general help!


(This post was edited by cademan on Jan 29, 2008, 10:46 AM)


techchris
Veteran

Jan 29, 2008, 6:14 PM

Post #9 of 12 (1567 views)
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Re: [cademan] Need Help [In reply to] Can't Post
no offence meant but the original post was about vertical scan collapse ie horizontal line across, not a vertical line up the screen,which could well be s- correction or flyback troubles


cademan
New User


Jan 29, 2008, 10:02 PM

Post #10 of 12 (1563 views)
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Re: [techchris] Need Help [In reply to] Can't Post
Mmmmph (lol) my bad! I meant horizontal line. See what age can do to a person. I sold all my television test equipment years ago, and was given a TV that won't turn on. I still have my trusty volt meter. All resistors check out, the fuse is good but it's almost all microchip driven (I hate 'em). Can you teach an old dog new tricks? Can you give me some insight?


techchris
Veteran

Jan 29, 2008, 10:42 PM

Post #11 of 12 (1557 views)
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Re: [cademan] Need Help [In reply to] Can't Post
check the horizontal out transistor for short circuit.if ok check for 5v on the micro,and check the secondary diodes off the power supply for short circuit or a short across one of the supply lines, from cathode end to chassis


rrobor
Veteran

Jan 30, 2008, 9:24 AM

Post #12 of 12 (1547 views)
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Re: [techchris] Need Help [In reply to] Can't Post
Come on lets not get silly here a vertical line ----- is lack of vertical scan. There is no way other than some magical and unlikely issue that its the tube. The flyback transformer would have to lose a wind to cause it. As a pro tec for over 30 years I have had that twice and I averaged 12 sets per day 5 days PW. That the output IC is gone, the booster cap and perhaps the feed resistor. Anyone want to guess how many of those Ive changed. Next it may be the jungle or now the micro, but lets be honest this is bread and butter stuff, I fixed those in my sleep, lets not get into the one that got away, this just aint it.

 
 
 


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