I just parted out an LG 46" 1080, and peeked inside the lamp section....yikes! 16 horizontal ccfls with their HV caps on the end of the boards. Looked back at the inverter stage and noted the 1200v at 140mA output. Since this unit only had 2 HV leads and 2 inverter transformers, how is the voltage supplied/distributed? The LCD monitors usually have one xformer per tube, and all the complex feedback to the logic board. Do the LCD TV's have similar set ups? If one tube fails, does it shut down like the monitors do?
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Re: TV CCFL circuits in general
read post #33
https://www.badcaps.net/forum/showth...t=12151&page=2
Al.
Well that my not be what you ask but it's intrestringLast edited by alexanna; 12-11-2010, 08:28 PM.Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!
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Re: TV CCFL circuits in general
Thanks, and that helps. I suppose in this 46" TV, then we're running 8 ccfls from one xformer, using a sort of series circuit and one that provides feedback to shutdown if needed. Interesting. I'll see if Electrotanya has the schematic, just to satisfy my curiosity.Comment
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For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.
Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.Comment
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Re: TV CCFL circuits in general
my mistake...I meant to say parallel. Still wondering how they maintain a complex feedback of individual lamps in such a circuit with only two big sources of HV. Just looked at a post with multiple individual xformers feeding each tube. That I can see, the other setup seems very ingenious and cost effective. Granted, this LG I was parting out is just a year old...Comment
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Re: TV CCFL circuits in general
They probably have some sort of ballast built into the lamps themselves, or onto the board, before they sum into the transformer.A working TV? How boring!Originally posted by PeteS in CAComment
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Hi everyone!
I managed to get my hands on a rough condition B&K 707 for "the best price" because it was not working. It's my first tube tester and I'm really wanting to get it up and running. I downloaded that manual that has the schematics and tested every resistor and capacitor and replaced the ones that failed. I replaced the missing 83 rectifier tube with a used but tested-good one. I also have a number 80 rectifier tube that I have used in tests before I found the 83 tube.
Initially I noticed that I was not getting the red on-light to turn on, but it... -
Hi,
This monitor previously is my main working monitor which i have been using for 8~9 years. Yesterday, when i switched on my pc from fresh to power on, the monitor is just black no display. I started dismantle to look inside the monitor power board but nothing looks suspicious or burnt. So i took my external ccfl inverter to try to power the monitor ccfl lamps which consisted of 2 lamps on upper part and 2 lamps on the lower part.
Found out the upper ccfl lamp which is supposed to connect to cn304 on the power board did not light up. Then i installed a used working... -
Greetings everyone,
I have a HANNSG Hi221 monitor that exhibits two seconds to black issues (backlight goes off, display is still on as confirmed by shining a flashlight on it) with some additional oddities...
The monitor failed on me with a standard "2 seconds to black" some time ago prompting me to initially replace most of the electrolytic capacitors (some of them were bulging/leaking).
Things kinda sorta worked for a night, then the problem returned along with some flickering and "buzzing" noises.
Upon closer inspection... -
Recently I acquired an Eico HFT 92 AM/FM radio made back in 1958. The unit has had some decent modifications done such as replacing the rectifier tube with silicon diodes and replacing the main filter capacitor with electrolytic capacitors. When I powered it up FM wouldn't tune past 105Mhz. I checked the FM tuner front end assembly and found a capacitor not soldered to the coil from the Plate B+ to and ground on the other side of the coil. Some calibration was needed on the trimmer capacitor on the tuner. My question is AM is extremely weak. When I tap on the tube I get all kinds of snapping and... -
Good time of day to all,
I have a laptop - PC Specialist PC50DS - that I am attempting to repair.
(Also manufactured and (was) sold under names of Clevo PC50DS and Schenker XMG 15 Pro)
Laptop is:- Not powering on
- Not taking charge.
Before I proceed, I would like to add some context: I am by no means experienced in laptop board repair. I have one repair under my belt, for which I had access to Boardview schematics (.brd), which helped me greatly by being able to see HOW and WHAT WITH each component interacts and "Follow the circuit"....03-16-2025, 03:56 PM
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