Re: no backlight supply volts hisense ub50ec591uwt
thanks for cct now im off to check volts around the led driver ic
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Re: no backlight supply volts hisense ub50ec591uwt
full raw dc 378vLeave a comment:
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Re: no backlight supply volts hisense ub50ec591uwt
What voltage do you have between the legs of either of the 68uF 450V capacitors
The led voltage is given as 200V @ 400mA which appears to be missing.
Possible schematicLast edited by dick_barton; 08-04-2020, 05:33 AM.Leave a comment:
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no backlight supply volts hisense ub50ec591uwt
hi im no stranger to these and its almost always the backlight leds
but not this time ive stripped down and tested all leds and they are all good .
the psu comes out of sby and sound is present the 12v and 16v supplies are all good but the backlight feeds are only 3volt ,
this has two chains of leds and two plugs feeding
when i unplug the feeds even with peak hold meter theres only 3v the two fets ca5b3d that supply the tx test ok,
and i now suspect the surface mounted driver ic msc lx 27901 id ,i wonder
does it contain a comparitor cct that monitors the two strings of leds ?
and if the two current demands of the strings arnt the same then it switches off the fets ?
any ideas pleaseAttached Files -
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Hello Sharp TV experts
Our Sharp LC-80LE642U displays one short one long flash error code which is a backlight error. I went into service mode and there were 8 lamp error counts recorded. I reset the count to 0 and did a reset. The last monitor error cause was 16 B00014639:12. 16 is the code for backlight error. I tried to power the tv up but went back into error mode.
> I checked voltages on the power supply board and they all check out .. including 3.28 volts at the error pin.
> There is power to the cpu and T-CONN and no faults found there. The cpu has a flashing...01-24-2025, 11:51 PM -
This was my initial thread.. https://www.badcaps.net/forum/troubl...-m-at-wits-end
(All the Electrolytics are brand new.)
I started a new one, hope that's ok, because my question is different now! (Strangely enough, after I walked away for a few weeks, it stopped lighting up at all!!)
I am determined to fix this power supply because I have the skills to replace bad components, I just need to find out... -
Background:- Hisense 65H6570G stopped working and I root caused to a burnt out LED in the backlight. (For anyone interested the power light pattern when the backlight has gone is 1) two long flashes, 2) a very short third flash, then 3) back to solid red )
- I replaced all 6 of the backlight LED strips with these replacements: amazon
- The TV worked again perfectly for ~2 weeks.
- After that 2 weeks the colors became "inverted". The TV powers on and shows the boot screen in correct colors initially (aqua hisense logo on black background, pic on the left) but a few seconds after boot
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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... -
Currently trying to save a 65” 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 life…..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...
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