Got this LG tv, no picture or backlights, check volts and get 24v ok, but blon only .01v, so suspect mainboard, can these be swapped out ok?
Attached Files
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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... -
Hi everyone.
I am diagnosing my personal laptop, because it wont power on and no leds light up.
At the dc-in there are 8 pins, 1 and 2 shows healthy 19.66 volts. The next three are ground, but the 6th one shows .283 volts. This is strange to me, it should be 3.3 or 5 or aome volts not 0.283v. As I am new to this, I would like some guidance. Please someone advise me on what to check next.
Oh the boardview and schematics I am using is for a similar model as I cannot find the proper one anywhere. Quanta DA0P5HMB8F1 rev F. Nowhere on the internet.09-23-2025, 12:13 PM -
Hi everyone,
Brought a non functionnal PS5. Apparently only a bad PSU...
No beep, nothing.
After some tests i found this :
- PSU is fine (12 volts stable)
- 12 volts line is shorted
- DA9065 was fried, F7003 also => Replaced both of them, short is gone on 12 volts line, no dead short anywhere else.
- By the way, nothing change. No signal, no power, no beep.
Mesuring all rails with my workbench psu (12 volts input)
- 0.00 amp drawing
- 12 volts, 5 volts, 2 volts, 1,15 volts are presents (suppose new DA9065 do is... -
Hello, I have a problem with my Samsung UE48H6410SSXZG with the main board BN41-02156A and the power board BN44-00709A. Everything seemed like this, the TV could no longer be switched on, the standby LED always flashed 5x2 times. Backlight was off and no sound from TV. Also made the flashlight test and there was no picture.
I made the following tests:
1. Disconnected the main board from Power Board = backlight works.
2. Connected the main board and disconnected the T-Con = backlights does not work.
So I ordered a main board from Ebay also BN41-02156A but from... -
Good day to all. The bite alarm drains 9-volt Krona batteries. Current consumption when switched on is about 50 mA. I wiped the board from oxides, I will attach a photo (on the board there is a j3y transistor and a 7533 stabilizer, the microcircuit is erased = (the 3.3-volt stabilizer heats up weakly. I replaced it, nothing changed. I unsoldered the microcircuit, the consumption disappeared. The resistance on the pins of the unsoldered microcircuit from the point clockwise is more than 2 megaohms, the 11th leg is presumably ground. I warmed up the microcircuit, the consumption does not change....
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