I have a JVC AV27320 TV that is only few years old. The screen of the set becomes to too dark in recent week. The color is also turning poor, which I don't know if it's caused by lossing the brightness. I have adjusted the Brightness on front panel to max and even adjusted the Screen on the FBT, it didn't help much. Does anyone can help on this set or know where can I get a free diagram for the set. Thank you for your help.
Hi solution #2 was correct. the adjustment knobs r on what's called the "flyback" i adjusted the bottom knob and the difference was from "night to day" !!!
I think it may be a possibility of low heater voltage. The heaters are the filiments inside the picture tube that gives off the electron emissions that are guided through the tube by the grids and bounch on to the CRT face. If the emissions are low the picture will look all muddy and washed out with poor color. This could be a bad coil or resistor or even a leaky capacitor in the filiment circuit. Although Jomaru could be correct by saying the picture tube is bad also, but I have seen sets that had poor connections in the heater circuits that were condemded for bad CRTs as well. Like he said if you have no TV repair experience, play it safe and call in a tech to assist you in this repair, as there are no user replaceable parts inside this set. A tV set is no place to be experimenting inside if. Good Luck PS please do not forget to rate this thread
oops almost forgot There is a AV27260 available for free here http://www.eserviceinfo.com/downloadsm/1... Click on the small red 0 Its not the same model but is almost the same with the same parts inside.
OOps forgot to say, you must download part 1 and part 2 for the service manual to open up propery
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Thanks for your help. I was about to trash my TV and buy a new one. You saved me lots of money. I adjusted the brightness on the back and it's like having a new TV. Thanks again
Brightness on the JVC AV27320
by rtaylor013 ,Aug 07 '06
Pros: The brightness problem was easy to fix.
Cons: I shouldn't have had to adjust the television in the first place.
I was recently given a JVC AV27320 television by a neighbor that was moving he gave the television to me because it wasn't bright enough. So with a flashlight and a small Phillips screwdriver I adjusted the brightness with the master controls in the back of the set. On the back of the set; the right hand side you will find two vertical slots. The top one is for focus. The bottom one is for picture brightness. With the flashlight I looked into the slots located the place for the Phillips and adjusted the brightness. Simple I know but not all fixes are hard.
I was NOT electrocuted! I took the advice proffered by Dave Mil. IT WORKED!!!! Took about 30 seconds. I'm a 72 yr. old widder woman who's been suffering for over 3 years with this DARK pix. If there was a night scene in a good movie-I'd have to go to another tv. This condition was extant from the day of purchase! Many thanks to Dave & the TEAM for this great site!
If your tv is older than 5 years it qualifies for a possible bad picture tube but it can also have a regulation problem in the power supply making all the voltages supplies lower than normal,specially the volts supply to the horizontal output transistor,he energizes a transformer that produces the high voltage that lights up the picture tube.You can purchase a service manual at http://www.servicemanuals.net/ ,you can also check your local library,in big cities some libraries have squematics.If you need more information please let Us know.
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Thank you Jomaru,
The TV is less than three years old and was not used very offen.
Where can I measure the regulate voltage you mentioned and what could be the possible defective part. I know that I can purchase the service manual on line. However I want to know if there is a site I can find it for free.
Thank you again for your help.
Thank you Techman.
Please tell me what is the voltage for this CRT heater and which part can be replaced to adjust the voltage. Is there other possible defective parts that can cause this problem?
Looking forward to hearing from you.
james15602
I also have a JVC AV27320 with a lack of brightness, esp. for night scenes. Solution #2 described in this site was the fix. 2 minutes to find a flashlight and phillips and just a very small tweak of the bottom screw and I was back in business. Probably less than 1/12 of a turn if you think of it like a clock. Use the menu function to reset the brightness on the front panel control back to the mid position or slightly below mid position before you make the adjustment. After adjustment, use the brightness menu to run the level up and down scale to make sure you are satisfied with the result, and check with day and night scenes.
Just wanted to say thanks. After two years living with a JVC that was too dark and all the frustration thinking it was a lemon, your simple fix worked fantastic!! Thanks again and happy holidays! :-)
I had the same problem with my set and was in the same situation as Julip, thought I was going to have to junk it and spend big bucks on one of the new ones. I didn't have to because you guys were there to help. I tried the "Best Solution" as shown in this article and it worked like a champ; my TV is back to normal (before, the screen was very gradually getting darker and darker even though I had the brightness and picture controls maxed out high to compensate). One thing I would mention is that the slots in back are VERY narrow and so you must have a very small Philips head screwdriver to be able to reach the screw inside. As it happened, I did not have one that small but I was able to make do using the smallest Philips head screw tap I had. Thanks again!
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