Mitsubishi LT-52246 has sound but no backlight, i.e. the televised images are visible using the flashlight test. I am reading voltages that are what I believe in range and am having a tough time discerning which components have gone bad. Anyone have any insight to a surefire method to determine which board needs to be replaced? ...or might the ccfl's be at fault -- and how do I tell? I'm a novice here so step by step would be greatly appreciated. Thanks!
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Re: Mitsubishi LT-52246 has sound but no backlight
Old LCD CCFL TVs are obsolete and usually not worth it to repair. The inverter circuits are a high shock hazard with thousands of volts. That being said, I have seen bad transformers, shorted FETs and bad caps on inverter boards. The bulbs are likely near end of life at this age as well.Last edited by neilc6; 07-02-2021, 04:02 PM. -
Re: Mitsubishi LT-52246 has sound but no backlight
Thanks neilc6 for the quick reply. I realize the set is rather old at 12 or 13 years, but man it has got one gorgeous picture, or had one anyhow. It sounds like you have seen most of the problems like this related to bad components on the inverted boards. As such, if I can source replacement boards at a good price it might be worth a shot to fix it. If it turns out to be a bad ccfl it would have to hit the scrap heap. Thanks for your help. Anybody else care to chime in?Comment
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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... -
TCL 75S421
PSU BOARD: 40-L402H8-PWD1CG
it shows not even a flash of backlight when powering up.
but the tv appeas to turn on and i can hear the sound of the menus moving and clicking. i can power down the tv with the button.
testing the backlights with my tester all 4 strings lit up and showed similar voltage drops. around 110 or so.
unplug mb and leave only psu plugged into backlights (PSU + BL SELF TEST MODE?) does not light the backlights.
i do see 24v but 0v on PSON and BLON (i didnt write this down tho so cant be sure)
with mb connected, PSON... -
so i took out one of my spare gigabyte ep35-ds3r mobos from storage for use to do some cpu, ram and video card testing of stuff i bought from ebay and got for free from momaka. he bought 50 e8400 cpus for cheap from ebay some years ago and i decided to help him relieve him of some of his supply since he had waaaay too many!!
what did we say about hoarding too much stuff and depriving others of them?! *cough* socialism *cough* lol! 
i had to blow some dust off the board and heatsinks with the datavac as i didnt clean it up before putting it in storage. after finishing... -
I have a 60 inch Samsung UN60EH6000F flatscreen TV. The screen went black a few months ago Sound is good, backlight is good, no menu. I replaced the TCon board with a used board purchased from Ebay. It worked fine for a 3-4 months, then the screen started ‘fading' back. Once again, sound is good, backlight is good, no menu. However, this time the picture looks fine for about 10-15 minutes, then fades back. If I power cycle the TV, the display reappears, for another 10-15 minutes, then fades black again. Repeatable ever time.
I ordered a supposedly ‘new' Tcon board this time, and... -
Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.
Upon bringing it home and plugging it up, it showed a standby light.
I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.
The screen seems to blackout and stay black, but with a flashlight I can see the display.
With my Playstation 4 connected via HDMI, and running a game I can hear sound.
Assuming...
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