Samsung ue55hu8500t tcon board fuse blowing

[Chrissygizmo]

Hi , I've got a Samsung UE55HU8500T that has sound but no picture, I've had it open and done a quick check of voltages etc, I found that the F2 fuse on the tcon board had blown (T-CON BOARD VD_STV5565EU22BC6LV0.3 -) so I replaced it with a similar value fuse but still nothing, ten I noticed the replacement fuse had blown too . I would appreciate any help with this. Thank you in advance

[diif]

Re: Samsung ue55hu8500t tcon board fuse blowing

I see two fuses, did you check the diodes next to them, you have a short somewhere.

[Chrissygizmo]

Re: Samsung ue55hu8500t tcon board fuse blowing

I see two fuses, did you check the diodes next to them, you have a short somewhere.

Thanks for your input, no I only checked the fuses , I will check the diode later, Could I just ask you to point out the diode that I should be checking please? I was going to go around the board and googling each component to find out which ones are diodes , as you can gather I'm new to this.

[dick_barton]

Re: Samsung ue55hu8500t tcon board fuse blowing

Diodes are prefixed with D so D111 & D121 are diodes

[Chrissygizmo]

Re: Samsung ue55hu8500t tcon board fuse blowing

Diodes are prefixed with D so D111 & D121 are diodes

Brilliant, thank you , I will update later tonight

[Chrissygizmo]

Re: Samsung ue55hu8500t tcon board fuse blowing

I see two fuses, did you check the diodes next to them, you have a short somewhere.

Yeah I checked both fuses , I've just checked both diodes and here's the readings..

D111 - 4GZNJ - 559 / OL

D121- 4GZNJ - 000 / 000

I am guessing that D121 needs replacing and is there a compatible diode I can try for testing purposes tonight as I'm having trouble trying to find the exact same one on the old boards i have to hand .
Thanks

[R_J]

Re: Samsung ue55hu8500t tcon board fuse blowing

D121 is a littlefuse SMCJ14A tvs diode (14v protection diode) you should be able to remove it and check the board operation. If the board works ok, install a new protection diode.

[Chrissygizmo]

Re: Samsung ue55hu8500t tcon board fuse blowing

D121 is a littlefuse SMCJ14A tvs diode (14v protection diode) you should be able to remove it and check the board operation. If the board works ok, install a new protection diode.

Thanks for that, do you mean I can remove the diode and put the board back into the tv to try it ? If I get a picture then order a replacement diode ? Put a new fuse in before trying though I'm guessing? I thought by removing a component from anything there wouldn't be a circuit so it couldn't work ?

[R_J]

Re: Samsung ue55hu8500t tcon board fuse blowing

Yes you can remove the diode, install a fuse and check the board. The diode is there to protect the 12 volt line from any spikes above 14v, For some reason it shorted, either from a voltage spike or it was just it's time, If there was a voltage spike, both protection diodes should have shorted.
The diodes should be between ground and the +12 volt input

[Chrissygizmo]

Re: Samsung ue55hu8500t tcon board fuse blowing

C

Yes you can remove the diode, install a fuse and check the board. The diode is there to protect the 12 volt line from any spikes above 14v, For some reason it shorted, either from a voltage spike or it was just it's time, If there was a voltage spike, both protection diodes should have shorted.
The diodes should be between ground and the +12 volt input

Ok, I really appreciate your help, I'm going to give this a go now, I'm not slow , honestly �� , but just to grasp properly what you have just said - is this correct?

Remove the diode
Replace the blown fuse
Leave diode position empty
Replace the board & try ?

I just can't get my head around how it can work with a break in the circuit... I don't really care though so no need to explain that to me �� and

Thanks again ��

Edited***

I've done this , put tcon back in place, but before switching on I went around with the multimeter and found that both fuses & diodes are earthed. Any suggestions on what to check for ?

[R_J]

Re: Samsung ue55hu8500t tcon board fuse blowing

Ok, I really appreciate your help, I'm going to give this a go now, I'm not slow , honestly 🤨 , but just to grasp properly what you have just said - is this correct?

Remove the diode
Replace the blown fuse
Leave diode position empty
Replace the board & try ?

I just can't get my head around how it can work with a break in the circuit... I don't really care though so no need to explain that to me 😊 and

Thanks again 👍

There is not a BREAK in the circuit, The diode connects ACROSS the 12 volt input.

[budm]

Re: Samsung ue55hu8500t tcon board fuse blowing

Just think of it simple example, such as AC outlet strip, one with surge protector device installed and another one without. If you remove the surge protector device from the outlet strip with surge protector, the outlet strip will still work and provide power to the socket but it will no longer has surge protection.

[Chrissygizmo]

Re: Samsung ue55hu8500t tcon board fuse blowing

Just think of it simple example, such as AC outlet strip, one with surge protector device installed and another one without. If you remove the surge protector device from the outlet strip with surge protector, the outlet strip will still work and provide power to the socket but it will no longer has surge protection.

I've decided to order a new tcon board as they are quite cheap on spares2repair..

This is probably an obvious question but I've read somewhere that when the cable from the one box isn't plugged in to the tv there is a logo on the screen to let you know, would that logo be displayed on a tv with a bad tcon ? I don't want to buy a replacement tcon if the panel is dud .

Thanks

[R_J]

Re: Samsung ue55hu8500t tcon board fuse blowing

What BOX are you talking about? If the fuse is open, the t-con is not going to work at all so you will not see anything on the screen.
Remove the shorted diode, check it after it is removed to be sure IT is shorted and not something else on the board, If it is just the protection fuse that is shorted, install a fuse and try it.

[Chrissygizmo]

Re: Samsung ue55hu8500t tcon board fuse blowing

Sorry my bad, this TV has a Samsung One connect box

[Storyteller12]

Re: Samsung ue55hu8500t tcon board fuse blowing

I have this same board. Also check the ceramic capacitors. Usually one of them is bad.

I’ve seen it on c104 or c103 and also cd3011