Samsung UN46C6300SFXA keeps clicking

[tibimakai]

I have picked up this TV and I don't know where to start.
The person who sold it to me, replaced some capacitors, purchased from Mouser. The replacement did not change the problem.
It seemed like he knew what kind of capacitors to purchase. He even gave me the extra capacitors that he purchased.
All the voltages are turning on and off.
I can measure these voltages 384V, 12.27V, 5.2V, but only for a couple of seconds and then they turn off and then right back on.
The red LED is on all this time without any blinking.
Backlight doesn't turn on at all.
Where should I start?

[tom66]

Re: Samsung UN46C6300SFXA keeps clicking

Main board fault is very likely. Replacement only usually.

However, do isolate the T-con first and see if set powers up with backlight. If so, you have a shorted T-con or panel.

[tibimakai]

Re: Samsung UN46C6300SFXA keeps clicking

Thanks for the fast reply.
I have tried disconnecting mainboard from power supply, which didn't do anything. TV did not turned on at all, not even the LED.
With the T-con disconnected, the TV just did the same thing, keeps clicking with red LED always on.
I understood that with the newer TVs, if you disconnect the wire harness between the main and PS, the TV should turn on the backlight.

[tom66]

Re: Samsung UN46C6300SFXA keeps clicking

May not apply for new Samsung LED, using multi-region dimming, it might need commands to set up the dim level on each LED.

[tibimakai]

Re: Samsung UN46C6300SFXA keeps clicking

I have took some measurements on the PS connector and this is what I have got:
PS= 0V
SB= 5.3v this is the only one stable voltage
D5.3V= 5.3V
GND= 0V
GND= 0V
H-Sy=4.5V
PWM= 3.99V
BL= 0V
DET= 3.3V
Vamp= 17.08V
Vamp= 17.08V
D5.3V= 5.3V
D5.3V= 5.3V
GND= 0V
GND= 0V
D12V= 12.76V
D12V= 12.76V
D12V= 12.76V
So it seems that the STBY is working, but everything else is turning on or off.
I have read at justanswer a similar case, but with a different model number and after they have replaced the mainboard, it didn't fix the problem.
After replacing the power supply, the TV worked as it should.

[budm]

Re: Samsung UN46C6300SFXA keeps clicking

You can disconnect just the PS_ON pin and the BL_ON pins to see if the Voltage will go up, we just trying to find out if it has built-in pull up resistors for these two signal pins on the power supply board, if not, then you can force on using the resistors between 5v and th those two pins as usual to force it on.

[tibimakai]

Re: Samsung UN46C6300SFXA keeps clicking

OK, I have removed both pins and it didn't turn on.
I have used a 2.2Kohm resistor and it turned on with a flickering backlight.
The 3.3V measured by itself(unplugged) it shows the fluctuating 0V and 3.3V.
So it seems that the problem is from the mainboard.

[budm]

Re: Samsung UN46C6300SFXA keeps clicking

I never have any luck trying to repair Samsung main board yet, not like old Vizio with just bad regulators IC's.

[tibimakai]

Re: Samsung UN46C6300SFXA keeps clicking

Probably nobody can repair them on this forum.
It's safe to say that I need another one, no?

[tibimakai]

Re: Samsung UN46C6300SFXA keeps clicking

What could cause the PS_ON to keep switching on and off? Can be some bad SMD capacitor causing this?
Which component gives the command to turn on the PS? The main processor?

[tom66]

Re: Samsung UN46C6300SFXA keeps clicking

I would be surprised for now if a capacitor was causing it.
The main processor or sub micom generates the power on signal.

Depending on the architecture (cheap to manufacture vs. cheap to design) they may have gone for one of two solutions:

1. All in one chip that handles everything. Video, audio, processing. This is probably not the case, we can see what appears to be at least three heatsinked chips, with the option for a fourth. (This is expensive to design, but good for cheaper TVs as it costs less to make.)

2. Multiple chip option - what they've done here. In this case the on-off signal may come from any one of the chips or another sub micom (sub microcontroller.) The sub micom often handles the IR and side buttons too, passing information to the main micom. Sub micom design may also use less power. (Cheaper to design, from off the shelf parts, if you want to get a low-quantity TV shipped, like an early LED prototype. But costs quite a bit to make...)

The video flow on this board appears to be, starting from the bottom right corner: an input buffer/conversion IC, which converts formats to one standard format, an applications processor (likely running Linux), and the frame rate converter IC. The sub micom may be on the bottom, or there may not be one, and it is on the applications processor. You can tell the middle processor is the applications processor because it's the only one with flash memory in addition to RAM. The flash memory stores the software.

[tibimakai]

Re: Samsung UN46C6300SFXA keeps clicking

So, if the PS_ON state changes from on to off and then on again, then one of the processors are bad, no other component can do this, right?

[tom66]

Re: Samsung UN46C6300SFXA keeps clicking

Well, there could be a protection circuit, such as a DC rail from PSU being bad, a T-con fault (maybe T-con not plugged in considered same as faulty T-con), maybe even bad firmware for the applications processor. So, no, maybe there's more than one possible cause, and you need to do your best to isolate each by making tests and eliminating causes. If you're looking for easy fixes... those are becoming rarer and rarer in the TV repair business.

My opinion on these TVs is the firmware is bad on the main board, and it must be possible to upgrade it/rewrite it but I do not know how. Short of desoldering the flash chip and programming it externally.

[tibimakai]

Re: Samsung UN46C6300SFXA keeps clicking

I have found a compatible board for this TV, shopjimmy confirmed it that it should work.
By comparing the original board with the "new" one, the new one seems "empty".
What I mean there is a big portion where is not populated with components as the original. Do you guys think that it's still OK?
Here is a picture with the "new" one and below is the original:

[tom66]

Re: Samsung UN46C6300SFXA keeps clicking

To me, it looks like it has no Motion Interpolation IC, unless that has moved to the chip with the black heatsink. Very big change between boards. Also, the applications processor has less RAM, and there's no video frontend IC. So you'd be taking a big chance.

It looks like Samsung made some major, major design changes (perhaps "f#ck, f#ck we need to get this product out in 2 weeks time for the holidays, just throw together what we've got" and "phew, sold a lot of them, LED LCD looks like it is a big hit, now lets cheap-ify it and milk this cow as much as we can")

[tibimakai]

Re: Samsung UN46C6300SFXA keeps clicking

You may be right there.
What would you do in my place? Specially that I was thinking of keeping it for myself?
A couple of days ago were two boards on Ebay, by asking the seller if they are compatible with my TV, somebody in that time grabbed them.
So when I was ready to buy them, they were gone.

[tom66]

Re: Samsung UN46C6300SFXA keeps clicking

I don't know if I'd ever keep a newer Samsung TV for myself. I just really don't trust the reliability one bit at all. I've got one at home, older LE40A656, for the parents, but as soon as I get the chance, I'll swap it out for a better model (probably when it keels over... Panasonic plasma would be nice and I've recently found a good amount of the older models with common 10 blinks issue.)

If ShopJimmy have a returns policy, then you'd only be out on shipping cost...

[tibimakai]

Re: Samsung UN46C6300SFXA keeps clicking

They don't have these boards, I would have to get it from Ebay.
I would keep it just for a while. The Sony that I have now, it's the third TV in a bit over a year.

[tom66]

Re: Samsung UN46C6300SFXA keeps clicking

What Sony do you have?

LED vs LCD you won't be impressed, there's hardly but a difference between them. LCD vs Plasma will impress you. LCD vs Tweaked/Modded Plasma will blow your mind.

Of course, that's only important if you watch films or care much about picture quality. Pops don't, so they've just got a basic 1080p LCD. My dad doesn't, but he's got poorer eyesight, so he's got an older 50" plasma I fixed (still beats the socks off my brother's new LED TV, though.) I care a lot over meaningless things, so I have a Panasonic plasma.

And this TV you got is weird. It's got some ungodly hybrid between AUO and Samsung panels. No idea how that works one bit. Looks like Samsung supplied the LED backlight, but AUO supplied the LCD glass.

[tibimakai]

Re: Samsung UN46C6300SFXA keeps clicking

Right now I have a KDL-46EX400. It cost me less then $100 repaired.
Before I had a Samsung 46A550.