Re: Samsung UN55HU6840 Solid red light, won't turn on
BLU_ON is 0V, unless I remove the MB, that becomes ~3.3V. P_DIM1 is always 3.3V, with and without MB.
Yes, I don't see any image or sound, not even backlight. I get the backlight only if I remove the MB.
AlexVaq
New Member
Last Activity: 08-12-2021, 10:26 PM
Joined: 12-17-2020
Location: Salt Lake City, UT
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Re: Samsung UN55HU6840 Solid red light, won't turn on
Hi budm, thank you for your help!
I do not have the remote, so I grounded the PS_ON using the button on the back of the TV. I connected PS_ON to arrow up, both of them are ~3.3V, and upon pressing the button up, everything goes safely to ground. The PS turns off when I do this, but as soon as I stop pressing the button (and stop grounding PS_ON), PS_ON raises again.
I'm 99% percent sure that pressing arrow up won't turn on the TV (actually, the manual says "long press power on, and that's not...Leave a comment:
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Re: Samsung UN55HU6840 Solid red light, won't turn on
Ok, if I connect to ground PS_ON, the PS turns off. As soon as I remove the ground connection, the MB turns on the PS, which I think is utterly wrong.
I'm tempted to buy a new MB, but it would be great if you had any ideas on how to repair this one. It's a pity to throw away the whole main board just because a capacitor/transistor etc is wrong, but I understand it can be extremely difficult to find the culprit.Leave a comment:
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Re: Samsung UN55HU6840 Solid red light, won't turn on
Got more info. The power on sequence is:
- Main board gets 5V (stand by). This seems right.
- Upon pressing the power on button, the voltage on pin PS_ON raises to 3.3V, and the PS returns 12.8V on the 13V lines. I think Vamp should be ~13V as well, but I'm not sure (other models are 18V).
- Then, the main board returns something on BLU_ON, up to 3.3V. This controls the backlight, 3.3V is maximum brightness.
- Then other stuff happens, which is not very relevant to the discussion.
My...Leave a comment:
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Re: Samsung UN55HU6840 Solid red light, won't turn on
BD228 is the one next to the 23. Can this be a diode?...Leave a comment:
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Re: Samsung UN55HU6840 Solid red light, won't turn on
Thanks for the answer! No, it is not a regulator transistor. It looks like a resistor or a small capacitor, but honestly I don't know what it is. I'll upload a photo when I get back home.Leave a comment:
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Re: Samsung PN50A510 P3FXZA Plasma Cycling On/Off
That was so helpful! I didn't even have to replace C102, just resoldered the connections and the TV fired again. Thank you guys....Leave a comment:
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Samsung UN55HU6840 Solid red light, won't turn on
Hi guys, I hope you can help me out with your experience.
I have this wonderful Samsung 4K TV that shows a solid red light when connected to power (standby, I guess), but refuses to turn on. When I press the physical button to turn the TV on (on the back), it does nothing. So I opened it and try some tests. So far I have checked:
- That the button works properly.
- That the backlight turns on if I disconnect the main board from the power supply.
- That the power supply board (a BN44-00755A) gives the right output without load on the CNm803 connector... -
Re: New Members - please post your introductions here
Hi guys, just trying to fix some good old TVs here. I successfully repaired a Samsung Plasma by resoldering a capacitor, and now I'm trying to repat the feat with a 4k TV. Hopefully, you guys will be able to guide me a little bit.Leave a comment:
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