JVC w/white lines
#1
05-14-01, 01:27 PM
Slightly different question. In my case it appears to be the TV - reproduceable when cable is disconnected. I get several inches of white horizontal lines at the top of picture. The picture in this area appears inverted (upside down). The picture is also off-center (black bar at top but none at bottom).
Set in question is a relatively new (2 yrs) JVC AV27920. Wife and kids leave it on for long periods. OK when watching letterbox format - horrid for all else. Help!
Set in question is a relatively new (2 yrs) JVC AV27920. Wife and kids leave it on for long periods. OK when watching letterbox format - horrid for all else. Help!
#2
05-14-01, 01:48 PM
Good Afternoon, jeffs763:
Gleaning the information from your post, I would make the determination that you have two conditions present: you're at the end of a long cable system and have a weak signal and (2) there's an electric motor involved. The electric motor is radiating or is showing up in the electrical system and causing the horizonal lines.
One program comes through okay? Okay, let's think about signal to noise ratio. A strong signal will overcome the problem and shove it into the background. So, think about improving the signal. Stop by Radio Shack and pick up a small signal amplifier, put the signal amp between your TV and the cable, and turn it on. Result: stronger signal and perhaps will over-ride the motor problem. Incidentally, a small signal amplifier may cost you $15 but it will give you a lot of relief and less stress.
Smokey
Gleaning the information from your post, I would make the determination that you have two conditions present: you're at the end of a long cable system and have a weak signal and (2) there's an electric motor involved. The electric motor is radiating or is showing up in the electrical system and causing the horizonal lines.
One program comes through okay? Okay, let's think about signal to noise ratio. A strong signal will overcome the problem and shove it into the background. So, think about improving the signal. Stop by Radio Shack and pick up a small signal amplifier, put the signal amp between your TV and the cable, and turn it on. Result: stronger signal and perhaps will over-ride the motor problem. Incidentally, a small signal amplifier may cost you $15 but it will give you a lot of relief and less stress.
Smokey
#3
05-16-01, 10:14 AM
Still confused
Smokey,
I took your suggestion and bought a signal amplifier. Hooked it up in between the digital cable decoder box and the TV set. No luck, still have horizontal lines at top of set.
It is OK when in letterbox mode because the top and bottom of set are unused (black) - not that I get any single program OK.
Notes: the same problem happens when cable is disconnected -also when viewing DVD or videotape. Also, the other TV sets in the house (running analog cable) do not have any problems. Cable switched out the box on Monday, still the same.
I'm still confused. Is there anything else I can look for? Thanks for your help.
I took your suggestion and bought a signal amplifier. Hooked it up in between the digital cable decoder box and the TV set. No luck, still have horizontal lines at top of set.
It is OK when in letterbox mode because the top and bottom of set are unused (black) - not that I get any single program OK.
Notes: the same problem happens when cable is disconnected -also when viewing DVD or videotape. Also, the other TV sets in the house (running analog cable) do not have any problems. Cable switched out the box on Monday, still the same.
I'm still confused. Is there anything else I can look for? Thanks for your help.
#4
05-16-01, 01:13 PM
Good afternoon, jeff763:
No doubt about it! I'm getting old. This Alzhemers is terrible.
I missed one word in your original post and it is the key to the problem. It's the word "inverted".
The problem is "Vertical Over-drive" and the white lines are vertical retrace lines. What has happened is a component failure between the vertical oscillator and the vertical driver circuit. The component is usually a capacitor that is leaking and allowing voltages to appear where they shouldn't be.
I know this is all very confusing. The problem is in the vertical driver circuit and it is overdriving the picture on the screen. The picture expands to the top of the picture tube and then reverses, and starts back down toward the bottom. The only thing that is going to fix this is a little time on the bench to find the leaking capacitor (or sometimes called a "Condenser"). Capacitors are designed to block DC voltages (Power Supply voltages within the set) and allow AC voltages (Signals) to pass. Your problem component is leaking and allowing DC voltages to appear where they don't belong. It's causing the vertical driver transistor to run "flat out" and will ultimately burn out the transistor from internally generated heat.
I'm sorry I misunderstood the description.
Smokey
No doubt about it! I'm getting old. This Alzhemers is terrible.
I missed one word in your original post and it is the key to the problem. It's the word "inverted".
The problem is "Vertical Over-drive" and the white lines are vertical retrace lines. What has happened is a component failure between the vertical oscillator and the vertical driver circuit. The component is usually a capacitor that is leaking and allowing voltages to appear where they shouldn't be.
I know this is all very confusing. The problem is in the vertical driver circuit and it is overdriving the picture on the screen. The picture expands to the top of the picture tube and then reverses, and starts back down toward the bottom. The only thing that is going to fix this is a little time on the bench to find the leaking capacitor (or sometimes called a "Condenser"). Capacitors are designed to block DC voltages (Power Supply voltages within the set) and allow AC voltages (Signals) to pass. Your problem component is leaking and allowing DC voltages to appear where they don't belong. It's causing the vertical driver transistor to run "flat out" and will ultimately burn out the transistor from internally generated heat.
I'm sorry I misunderstood the description.
Smokey
#5
06-04-01, 01:06 PM
Smokey,
Do you have any idea about whether this is a big job, or a small one? I'm in Silicon Valley, so the labor is likely to be outrageous.
I'm wondering whether or not to get a new set. I love the picture quality when it's working.
What I really need is an industrial grade set. Would like something inexpensive that will last. Won't buy another high-end set because wife and kids run it 24 hrs/day. Do you know of anything that would be a good choice for such abuse?
PS. 27" is minimum size as I'm a hockey fan.
Do you have any idea about whether this is a big job, or a small one? I'm in Silicon Valley, so the labor is likely to be outrageous.
I'm wondering whether or not to get a new set. I love the picture quality when it's working.
What I really need is an industrial grade set. Would like something inexpensive that will last. Won't buy another high-end set because wife and kids run it 24 hrs/day. Do you know of anything that would be a good choice for such abuse?
PS. 27" is minimum size as I'm a hockey fan.
#6
06-04-01, 01:54 PM
Good Afternoon, jeffs763:
I can't answer your question honestly, my friend, because prices vary so badly from one place to another. I am familiar with Silicon Valley, of course, and know the cost of living is above the roof....but you guys make great wages. The only thing I can tell you is to get some estimates on the job and make the judgment call yourself. You know how much money you have in the bank and what you can afford. I don't.
Give them the information about "Vertical Overdrive" as we posted on this thread. Most techs will "ballpark" a figure for you.
Industrial strength TV's? You came to the right house for that one. For the last ten years I have been building conference rooms and training centers for the government and had to produce equipment lists based on the worst possible abuse. I know what survives.
Television sets in this order:
1) Mitsubishi
2) Sony
3) Sharp
I loved these brands of television sets because they run forever (or so it seemed), had maximum manufacturer's support if and when a problem occurred, and they endured the worst of situations. Imagine a lone television set sitting in a room of 50 people who all claim to be an electronics expert. The set's only salvation was to be turned on and work the first time....or else! I can tell you some horror stories when the set didn't work. One rogue installation had a Hitachi that they bought on their own. By the time I got to it, we never did find all the parts to put it back together again.
Smokey
I can't answer your question honestly, my friend, because prices vary so badly from one place to another. I am familiar with Silicon Valley, of course, and know the cost of living is above the roof....but you guys make great wages. The only thing I can tell you is to get some estimates on the job and make the judgment call yourself. You know how much money you have in the bank and what you can afford. I don't.
Give them the information about "Vertical Overdrive" as we posted on this thread. Most techs will "ballpark" a figure for you.
Industrial strength TV's? You came to the right house for that one. For the last ten years I have been building conference rooms and training centers for the government and had to produce equipment lists based on the worst possible abuse. I know what survives.
Television sets in this order:
1) Mitsubishi
2) Sony
3) Sharp
I loved these brands of television sets because they run forever (or so it seemed), had maximum manufacturer's support if and when a problem occurred, and they endured the worst of situations. Imagine a lone television set sitting in a room of 50 people who all claim to be an electronics expert. The set's only salvation was to be turned on and work the first time....or else! I can tell you some horror stories when the set didn't work. One rogue installation had a Hitachi that they bought on their own. By the time I got to it, we never did find all the parts to put it back together again.
Smokey
#7
06-22-01, 02:46 PM
Follow-up - thanks Smokey!!
Just wanted to follow-up and say thanks to you, Smokey. The problem was as you described. It got worse (collapsed) a couple of days later. It was fixed by replacing a capacitor and an IC chip. Price paid was $115. Estimates from several shops ran from $100-$200.
Interestingly enough, one of the biggest repair-only businesses in the area (2 locations - 30+ years) was also the closest one to my home. When I gave them the info that we discussed, they told me it was the picture tube. I think they were trying to prepare me for a large bill.
Thanks to the info you provided me with and some subsequent reading of Sams troubleshooting and repair (so I could better understand) - I was able to recognize this and walk away. Thank you!
We found a reputable shop and are now enjoying the TV again in our home. Hope you have a great weekend!
Interestingly enough, one of the biggest repair-only businesses in the area (2 locations - 30+ years) was also the closest one to my home. When I gave them the info that we discussed, they told me it was the picture tube. I think they were trying to prepare me for a large bill.
Thanks to the info you provided me with and some subsequent reading of Sams troubleshooting and repair (so I could better understand) - I was able to recognize this and walk away. Thank you!
We found a reputable shop and are now enjoying the TV again in our home. Hope you have a great weekend!
#8
06-23-01, 09:51 AM
Good Afternoon, jeffs763:
It always makes my day when I hear that someone got a good deal and didn't get ripped off. Tell your friends about us at DoItYourself.com. We enjoy hearing from folks and love to help.
Come back and see us anytime.
Smokey
It always makes my day when I hear that someone got a good deal and didn't get ripped off. Tell your friends about us at DoItYourself.com. We enjoy hearing from folks and love to help.
Come back and see us anytime.
Smokey
