Samsung UE65KS9000 lines and reboot loop

[Storyteller12]

Re: Samsung UE65KS9000 lines and reboot loop

Looking closer at your pics in the first post. The 7th pic shows the cof tab burned up if I not mistaken. I had this happen on a 75” ks9000 model before.

I got it from a customer. I plugged it in to test and flames shot out the bottom. Opened it up and the cof tab caught on fire and burned a whole through it.

Unfortunately it’s trash at this point. But just to confirm you can pull the tab off completely and power on. Should stay on but will have a black strip on the screen when the cof tab was pulled.

[mrsith]

Re: Samsung UE65KS9000 lines and reboot loop

The COF tab isn't burnt, it was just reflection on that photo.
I'm suspecting mainboard at this point, a resistor or possibly a diode fail. Not sure how to identify VGH-responsible components though. Do you know if any boardview or schematic is available for this board? BN41-02504a / BN94-10989A

Also I have noticed one of the diodes (Ajs7, see photo) measurements seem odd, gives me 126 one way and 210 the other way. Shouldn't it conduct just one way?

Do different sizes of this model share the exact same maninboard? Seems like it looking on service manual. Thinking about sourcing replacement mainboard. Found one from UE65KS9000T but BN94 number slightly differs (BN94-10844F vs mine BN94-10989A). Would this one do? It's price is a third of bn94-10989a's available no ebay...

[nomoresonys]

Re: Samsung UE65KS9000 lines and reboot loop

.

[nomoresonys]

Re: Samsung UE65KS9000 lines and reboot loop

ok, my bad, i didn't notice it was from same size.

[mrsith]

Re: Samsung UE65KS9000 lines and reboot loop

The board I found is from the same size TV, think I'll give it a try then.

edit: not sure what's the difference between those two (if there is any). Mine says UE65KS9000TXXU, the cheaper ones I could find are from UE65KS900LXXH or UE65KS9090T(X/K)ZG (blurry photo). They're both BN94-10844f. Looking on the photos there is no visible difference between them and mine board. Why different BN number then? Not really keen to spend almost 100 quid for the same model as I have, but if there's any risk of incompatibility I'd rather not try.

[nomoresonys]

Re: Samsung UE65KS9000 lines and reboot loop

what is your panel number? white sticker on metal chassis someplace.

[nomoresonys]

Re: Samsung UE65KS9000 lines and reboot loop

or if the seller knows their business, they might be able to tell you if it will work, most don't want to sell the wrong thing, because usually only the shipping companies win when that happens.

[mrsith]

Re: Samsung UE65KS9000 lines and reboot loop

Cy-xk065fllv5h

Edit: ebay sellers say it's a trial and error and it might work, it might not. Googling/ebaying screen number doesn't clarify that, but I couldn't see any single proper match for my panel number + bn94-10844f.

I'll try to hunt my exact board number in reasonable price, in the meantime any advice/ideas how to diagnose and fix mine would be highly appreciated.

[nomoresonys]

Re: Samsung UE65KS9000 lines and reboot loop

.

[nomoresonys]

Re: Samsung UE65KS9000 lines and reboot loop

hard to get any conclusive results of what matches with this tv, I see one here that matches your part number so we know it will work, not sure if it's a good price or not: https://www.electromix.co.uk/main-pc...l5514-wg2.html

[mrsith]

Re: Samsung UE65KS9000 lines and reboot loop

I managed to get a straight answer - BN94 number has to be a match. I was digging yesterday and ordered exactly the same board as you linked above, it's the best deal available. The rest are ~£80+ so almost double this money.

Thank you once again and I will let you know as soon as the parcel arrives and I'll test it. Pretty excited, I really hope this is it.

Just in case though - how do I test diode packs? 2-legged diodes are straightforward, not sure how the 6-legged ones should be operating. Many many thanks

[mrsith]

Re: Samsung UE65KS9000 lines and reboot loop

Cannot edit the post unfortunately.

Please see pic attached: all of the top pins of all 3 diodepacks marked .e5 are shorted together and to the ground. I have checked bottom pins vs other bottom pins, no continuity. Top pins vs bottom pins, no continuity. I have tried every single combination possible, switched black and red probes etc. I think I'd expect middle pins to be ground, left side continuity top-to-bottom (or opposite) with the same on the right side?

I've measured kb0n diodes in different place and they seem to measure as expected - both middle pins are ground, there is one-way continuity between top and bottom left pins, same with right side.

Does it mean the .e5 diodes are bad, or that there's actually a short on that line?

Also there's an IC (photo included), what is it responsible for and is it any way to test it as well? Just want to completely rule out panel boards while I can still cancel the mainboard order today

[nomoresonys]

Re: Samsung UE65KS9000 lines and reboot loop

Wish I knew, I'll have to leave that question for the pros, was a good thread about them on here not long ago, I'll take a look for it.

[mrsith]

Re: Samsung UE65KS9000 lines and reboot loop

This big IC seems to be a flash memory so I can probably rule it out. It's just the weird diodes' behaviour that concerns me. And given that this sets have common problems with diodes...
If anyone could help me identifying them, I'd just try and replace all 3 to see if anything changes. I'll wait with trying new mainboard until I'm 100% sure the panel boards are okay.

Pros

[mrsith]

Re: Samsung UE65KS9000 lines and reboot loop

Been trying to identify these components over weekend. I have attached a datasheet of the closest thing I could find (same or similar package type SOC363 and marking E5), but I am far from being sure this is it. Any ideas how to proceed?

[mrsith]

Re: Samsung UE65KS9000 lines and reboot loop

Apologies for yet another post, I hate that I cannot edit older ones anymore.

So I decided to give it a go and check once again everything on the panel boards. Again didn't find any shorted caps, so started taking measures of all resistors to try and find something out of order.

Firstly I was a bit surprised that one of the resistors had only 0.2ohms while most of them ranged in Kohms. But going further there was something that looks like schottky diode - didn not get continuity either way on it. Checked with ohms - resistance was rising, from about 0 to 60k ohms. Switched probes and again - from negative values until around 28k ohms. The higher the value, the slower it went up. Took about 20-30 seconds until it stopped.

I have also noticed that if I took a probe away and put it back on a pin within short time (5 seconds?), it didn't raise from 0, started mid-way.

Not sure if this is wrong because I'm not entirely sure what smd I have been measuring (suspecting schottky but is it really it?), but the behaviour seems similar to the lines appearing on the screen - almost nothing on cold start, the longer the set is on, the more lines appear, up to the point they are over whole screen.

If it is indeed a diode, how can I identify it's values so I can search for replacement?

I'm getting repair-depressed again, desperately need a success

Any help at all highly appreciated!

[Diah]

Re: Samsung UE65KS9000 lines and reboot loop

take out all esd diode from the buffer boards and see if the short remain... tv will work with out them

[nomoresonys]

Re: Samsung UE65KS9000 lines and reboot loop

hopefully that's a cap you have been measuring, don't think diodes should read like that.

[mrsith]

Re: Samsung UE65KS9000 lines and reboot loop

It doesn't look like a cap, see last photo in my previous post.

Took all 3 ESD diodes out and measured the pads, still all 9 of them shorted to ground.

[nomoresonys]

Re: Samsung UE65KS9000 lines and reboot loop

i think that's a resistor.