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Hello, you will want to check a capacitor. I have replaced many of them in this power supply. When you remove it you will feel a slight bulge on one of the sides. It is c614a . Hope this helps.Leave a comment:
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TCL 75S421 New Backlight LED's Still No Backlight
Hello everyone, I got a TCL 75S421 with no backlight. I swapped out the LEDs and still getting nothing. I checked a few readings, see pictures below. Can anyone point me in the next testing area or what to look at next?Attached Files -
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This is A2289, board 820-01987-A. It came in with the screen not working. We could not see any image on the screen, so we ruled out a backlight issue and instead replaced the panel. The display now comes up, but no backlight.
I didn't see any signs of liquid damage, but there was some odd looking spots around U8400. F8400 has voltage on either side of it, and I have 5v present on R8444 and R8445. I did not have 3.2v at R8442 so I figured U8400 was bad, and I replaced it. After replacement, a brief probe to R8442 showed 3.2v so I assumed I had fixed the device. After reassembly however,... -
Hi, This model has bottom mounted leds . Got it with right ride 1/3 of the display black. So I checked the 6 + and - wire that powers 6 different zones and found that the 5th zone was open, which opens 6th zone too makes the right 1/3 of the display dark. Opened it and found one blown led on the 5th zone and shorted that path using solder. So now all the zones works when I check it using the bl tester , but when I put everything back together there is no backlight! The voltage I am getting when neg to chassis is 387v. How does that happen? Still individual zones working with bl tester .
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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... -
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 -
Hello, I have an "ASUS ROG Strix G713QR" laptop, and for approx. 3 months I have the following problems:
1. Laptop keyboard doesn't work
2. The backlight on the laptop keyboard doesn't work
3. The x2 side LEDs (red) on the laptop don't work
The power button works, the touchpad works, and all the USB, HDMI, Ethernet, etc. ports work.
I already tried to reinstall all the drivers and reinstall Windows. So I don't know what to try anymore that is software-related.
But I am strongly aiming that it is somehow a BIOS-related problem,...
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