Re: RCA RLED4778A No Backlight no Pic No Response
Same tv, same symptoms. 400deg for 10 mins in the oven for the main board and it works again
Same tv, same symptoms. 400deg for 10 mins in the oven for the main board and it works again
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Re: RCA RLED4778A No Backlight no Pic No Response
Same tv, same symptoms. 350deg for 10 mins in the oven for the main board and it works again. How strange is that, does anyone have an explanation for why this works, and how long has this fix lasted? Also is this the only set that this method has worked on?Comment
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Re: RCA RLED4778A No Backlight no Pic No Response
Bga on the mainboard overheats, try rigging up a fan solution to keep it cool, it may last a long time, without the extra cooling of a fan it might only last a day a week or a few months more than likely. I've seen where a second heating after tv quits working again may work but many times the second heating does not work.Last edited by nomoresonys; 04-26-2020, 09:47 AM.Comment
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Re: RCA RLED4778A No Backlight no Pic No Response
I expect it re-flows the solder. The TV I fixed was my brother's, and he gave it to his girlfriend. I've asked him about it at times and as far as I know it's still working, after 5 years.Comment
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Re: RCA RLED4778A No Backlight no Pic No Response
There's no reason to think if the BGA has only failed after 10 years then it should last another 10, if the reflow is done well. If it's not cost effective to reball then I reflow and I haven't had one back yet.Comment
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Problem
Fixing a dimming zone TV with LEDs not lighting up. Dimming zone circuit introduces added variable to diagnose LED and/or Dimming Zone Driver board? Some 1/2 rows of LEDs appears to be out in active dimming zone off AND some brightness flickering with active dimming zone high while playing changing video
Model & Board Pics
Conflicting Spec
Vizio indicate this TV has 10 dimming zones. However, LED strips and Zoned light driver connector suggest 12
https://www.shopjimmy.com/vizio-gj-2k1... -
Currently trying to save a 65β 850D that definitely has a main board issue. Power supply has standby voltage and PS ON pin shows 3.5VDC but main has no signs of lifeβ¦..no light under Sony logo and no optical port lit up. 12VDC is created by main board but no input triggers from main = no TCON 12V and no BL ON voltage present. I know about the trick of pulling the main to trigger the test pattern from the TCON but I get no backlight. If I jumper the 3.5VDC to TCON ON and BL ON, I can shine a light on the panel and see solid green, red, blue and white cycling. The 4 + backlight pins on the power... -
this tv is throwing me for a loop. do samsung tvs no longer have the backlight self test feature built into the power supply?
i tested the backlight with my LED tester and it lights up both strips. one of them reads 100v and the other reads 63.7v.
unplugged mainboard from power supply but left backlight plugged in, and then plugged psu wall power in. expected to see backlights light up but see nothing.
according to how ive diagnosed in the past, this would almost always be a bad power supply. replacement power supply was cheap like 20$ from ebay. but still i get not even... -
Full model of the TV is 65UJ6300-UA.BUSYLOR. TV was given to me by a relative as non-operational so I'm trying to get it working so I have a nice cheap upgrade for my living room. This is my first TV repair so if it sounds a little like I know what I'm talking about, I don't.
TV turns on and has audio, but backlight doesn't turn on. Getting 230v from LED+ to chassis. Also can't see anything with flashlight test. Another forum suggested I replace the LED strips because that's the most common failure on LG TV's and the flashlight test doesn't always show results.
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Hello all!
This post will mostly just act as documentation for my undertaken troubleshooting steps for this TV. Advice will also be appreciated for things to try next
Picked up the TV in thread title from a retail returns auction, symptoms were as described. I started my troubleshooting attempts by shorting the 19V PSU rail to the 3v rail with my multimeter... Doh. Big spark, dead PSU, TV not turning on anymore. Picked up a new mainboard and PSU locally from someone here in Sydney, wasn't sure if my butterfingers had killed both and was a big drive to pick them...
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