Can't turn it On and Off unless you unplug it....That sounds like your Microprocessor is locking up on you.
Have you ever tried turning it back off right after the TV is turned on, to see if the unit locks up? I'm thinking this problem might be related to the micro switching Modes, or possibly heat-related.
The way to test this....see if you can turn on and off before the Picture and Sound take over. Then turn it on...see if you can turn it off AFTER the picture/sound take over.
If it does, check to see if you can adjust volume and access menu.
These are step by step test procedures.
Lastly, Wait... give it an hour and see if you LOSE the ability to adjust volume or activate the menu. Then turn it off and see if you lose all control of the TV --check the remote, then check the Keyboard on the TV.
The Key tests are the On/off before and after the TV exchanges control to the Picture/Sound circuits.
That would be your DMD board, which is located right behind the fan in the center of your TV set.
The older models have some disassembly drawings, but they're worthless compared to the newer models --
Attachments are only available to registered users.
Not much detail in those....
The DMD part number is -- BP94-00478A
I Googled about 10 suppliers with your part number. It's either out of stock or no longer available.
I suspect the only way to get one right now is by buying an optical engine.
The part number for the Engine -- BP96-00087A
Here's one --
Looks like the engine is available, but the DMD isn't, so the only choice is to buy the Optical engine with the DMD board on it.
Once you get that part, let me know. I've got better pictures of the light engine and how to get it out.
Most engines on Samsungs all come out the same way. Your model has drawings only. They moved to pictures a few years later and those help you out a lot better than their drawings do.
If you have any questions, just ask
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Tips are greatly appreciated !