Samsung 55KS8005TXXE power cycling

[nomoresonys]

Re: Samsung 55KS8005TXXE power cycling

did not see your exact model but more testing there: https://www.youtube.com/watch?v=Aes6WiG2044

[baldharry]

Re: Samsung 55KS8005TXXE power cycling

its tough, here's a little of what Tampatac went thru, I can't see if he made another video on this tv or not, last thing he says I think, is that he's going to try to fix the mainboard but I don't see the next video, he may have gave up, not sure: https://www.youtube.com/watch?v=-_e9DFeZYKI


Diah or Lotus might have a better idea on whats wrong, mainboards are not an easy tackle.

Ok thanks, I'll have a look.

So strange that both mainboards act the same... The mainboards do look intimidating for sure

[Storyteller12]

Re: Samsung 55KS8005TXXE power cycling

If the tv won't stay on with the lvds cables disconnected from the panel then the only thing it can be is the main board. There is no tcon. If the backlights come on when the mainboard is unplugged then the power supply and backlight is good.

Don't order from Ali express. Try eBay and Ali express as a last resort.

[Storyteller12]

Re: Samsung 55KS8005TXXE power cycling

?

[baldharry]

Re: Samsung 55KS8005TXXE power cycling

If the tv won't stay on with the lvds cables disconnected from the panel then the only thing it can be is the main board. There is no tcon. If the backlights come on when the mainboard is unplugged then the power supply and backlight is good.

Don't order from Ali express. Try eBay and Ali express as a last resort.

Yes, that is what happens as you described.

Aliexpress was the only place to find a matching board $46 for the board, not that much of a loss. But now for a special price, only for you, a Samsung 55KS8005 carcass for $46. Only pickup, will not send

[baldharry]

Re: Samsung 55KS8005TXXE power cycling

Found this on another forum:

Question about the power cycling on this TV that others have experienced. They have replaced the main board on this and it did'nt fix the issue and now they are replacing the power board. My extended warranty is expiring soon and wanted to know if it's worthwhile for $75 for another year of service or not. Should replacing the power board fix this issue or is there something else that may come up later making it wise to extend the warranty.

Because my two mainboards make the TV behave "identically", is it the PSU to blame afterall...

[Storyteller12]

Re: Samsung 55KS8005TXXE power cycling

Take voltage measurements and compare with the legend on the board. But as I mentioned if the backlights come on when mainboard is disconnected that shows the power supply is good.

Your going down the rabbit hole now. Lol

[lotas]

Re: Samsung 55KS8005TXXE power cycling

Or maybe the panel is faulty. For some modern Samsung models, the TV will not start if the panel is not working and if you disconnect one or two LVDS loops, then it will not start either, you need to set jumpers on the motherboard (T-Con) to simulate the panel (as if it is connected).

[baldharry]

Re: Samsung 55KS8005TXXE power cycling

Or maybe the panel is faulty. For some modern Samsung models, the TV will not start if the panel is not working and if you disconnect one or two LVDS loops, then it will not start either, you need to set jumpers on the motherboard (T-Con) to simulate the panel (as if it is connected).

Oh, that's interesting! How do I know which pins to jump?

[lotas]

Re: Samsung 55KS8005TXXE power cycling

The signals "FB_TRDY" are responsible for the simulation, you need to connect all the loops (not including the TV in the socket) and measure these points between each other with a multimeter (for continuity), then turn off one loop and measure again and draw a conclusion where the jumper is placed, mainly between FB_TRDY_1 and FB_TRDY_3.

[Devil_rider]

Re: Samsung 55KS8005TXXE power cycling

Does this look like your psu?

[baldharry]

Re: Samsung 55KS8005TXXE power cycling

Thanks lotas, will try.

@Devil rider, yes. Except that the resistors basecolor is different, those are green, on mine pinkish or more maybe like pig skin. And thermistors, green on yours and black on mine.

[baldharry]

Re: Samsung 55KS8005TXXE power cycling

Oh almost forgot. Noticed that after TV has been in standby for a while, the voltages drop. For example, the Vamp and stby voltages drop down to 8.99 volts. That shouldn't be happening?

[Devil_rider]

Re: Samsung 55KS8005TXXE power cycling

There should be a 9000 series technical guide in which you might find the bypass and simulation procedure. The 2 series are almost identical.