Re: Polaroid P40LCD12
how to check if STBY voltage is coming back from main board, is next step?
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Re: Polaroid P40LCD12
Basically you have to find the 5V STBY and check if that voltage is going to the main board (which I think it is). Then you have to figure out, if the STBY voltage is coming back from the main board to the power supply, which turns on all other power supply voltages, while you "turn on" the TV.
So in other words: The only voltage always present is 5V.Leave a comment:
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Re: Polaroid P40LCD12
Ive only been able to find 5 and 3V3 present on the power board.Leave a comment:
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Re: Polaroid P40LCD12
Hi again,
I've had a look through the schematics and what not and am a bit lost I'm afraid.
What controls what? Do you usually get a standby voltage that tells the main voltages on the power board to come up or should 24V 12 and the rest be present all of the time?
Can I connect the SW connector to 3v3 or 5 to get it to fire up without the mainboard there and if so do I use a link or resistor?
Regards
DaveLeave a comment:
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Re: Polaroid P40LCD12
Hi thanks for the reply,
I've checked and found 5V present, What looks to be 3V3. There is no 24V but it doesn't seem to have tried to get that far. I'm thinking mainboard at the moment. There are a few voltages generated on board so I'll see if I can probe for these.
I was interested to see if these particular Vestel boards had any known faults.
I get a beep from the buttons on the front when pressed and there's 5V to that PCB.
As it stands I've found the datasheet for the Boards and will try the voltage fail test points to see if it's complaining about any one in particular and will have a go at reflowing the SoC and memory chip on the off chance that it's a bad ball on the BGA. I can only hope.
It seems that this TV may only have been £200 new so am a bit reluctant to throw 60 pounds at a new maonboard and PSU board.
Thanks again.Leave a comment:
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Re: Polaroid P40LCD12
Have you checked voltages on the psu 24v,12v,5v etc ?Leave a comment:
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Re: Polaroid P40LCD12
Having trouble with pics I'm afraid.Attached FilesLeave a comment:
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Polaroid P40LCD12
Hi all,
I've inherited the above tv. It has vestel gubbins, specifically a 17pw82-3 psu board and 17mb65s-3 mainboard.
When I push the buttons on the front of the tv there is a beep so 5 volts is there somewhere.
Am I better off starting diagnosis with the mainboard?
I can't see any poorly caps with my esr meter and have checked the components found in the online repair kits for the psu board.
Has anyone had experience with these TVs or these vessel boards?
Thanks in advance.
Dave.Attached Files -
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Hi everyone,
I've got a little "problem child": my Dell Latitude 7420 2-in-1, which had a faulty mainboard.
I replaced it, but ever since, the touchscreen no longer works — and honestly, I’m running out of ideas…
In Windows Device Manager, I just see an I2C HID Device with error code 10. Sporadically, the touchscreen is recognized correctly for just a few seconds, but I haven’t been able to determine under which circumstances this happens.
The touchscreen also doesn’t work in UEFI/BIOS, although it’s enabled... -
Hello,
I have an old MASTER TL-240 LED TV. Since it stopped working and it had a DVB-T receiver that is being dismissed in Italy, I've decided to replace the mainboard with a DVB-T2 one.
The original problem was that when switching on the TV, the power LED was transitioning from red to steady blue, without showing video or audio.
After checking some voltages on the power supply board (HKL-240101-B Rev. 1.4, HKL from now on) someone suggested me to replace the mainboard.
Now I have some doubts about how to connect the new mainboard to the old power supply.
First of... -
I have a Vizio M43-C1 stuck in a reboot loop with no backlight.
I've tested all the voltage rails coming out of the power supply and they are "normal" for this model (PS_ON & DIM go high when turned on, BL_ON & 3D_ON are close to zero due to backlight power flowing through the mainboard, 5VSB is 5V, and 12V is 19V, which is apparently normal for this board).
Basically, I get similar results to Garry in this post: https://www.badcaps.net/forum/showthread.php?t=80346
So, I've ruled out the PSU for now.
The reboot loop... -
Hi everyone,
I'm trying to repair my LG 49UB850V TV (WebOS 1.0, UHD model from 2014).
Mainboard model: EAX65684604
PCB marking: EBT62954607
SPI chip: Winbond W25X20CLNIG Problem description:
Originally, the TV would turn on (backlight and LED OK if I force them on), but it shut down as soon as any input was received from the IR sensor or remote. The backlight and power board were working fine.
After testing and verifying the voltages (DRY ON, PWR ON, 12V/24V rails), I suspected a corrupted SPI firmware. What I tried so far:- I bought another
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Hi
I have a QN65QN90A which was purchased around launch I guess making it about 1.5-2 years old... had been working fine until a few days ago, simply went black and would no longer turn on (at all). No standby light and no typical PSU relay click etc. Absolutely dead.
Pulled it apart without doing much research first, suspecting the power supply as it had a faint buzz (I guess due to the forthcoming found short), investigated PSU for some time and concluded there was no fault that I could spot with the board removed.
Came to learn after a bit more research...
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