Samsung LN52A750R1FXZA Turning on and off

[powerblackout]

Re: Samsung LN52A750R1FXZA Turning on and off

Nice, well you can test it in standby without turning it on, for the 160.

The TV turns on as soon as i connect the power supply to the TV.

I made a video of the process:
https://youtu.be/0Z0mq7BCWU0

The chimes sound, the backlight comes on, sits for ~10 seconds, then shuts off and repeats.

[powerblackout]

Re: Samsung LN52A750R1FXZA Turning on and off

I measured the caps. Most of them read fine, but two are weird. They're supposed to measure 1000uf but the meter is saying they are 4500. Guessing those are bad then lol?

[nomoresonys]

Re: Samsung LN52A750R1FXZA Turning on and off

n/a

[nomoresonys]

Re: Samsung LN52A750R1FXZA Turning on and off

The TV turns on as soon as i connect the power supply to the TV.

I made a video of the process:
https://youtu.be/0Z0mq7BCWU0

The chimes sound, the backlight comes on, sits for ~10 seconds, then shuts off and repeats.

Oh so no steady backlight then?

[nomoresonys]

Re: Samsung LN52A750R1FXZA Turning on and off

I measured the caps. Most of them read fine, but two are weird. They're supposed to measure 1000uf but the meter is saying they are 4500. Guessing those are bad then lol?

lol, was your meter set to capacitance?

[nomoresonys]

Re: Samsung LN52A750R1FXZA Turning on and off

Ok, lets try unplug inverter and see if it quits cycling, always unplug tv before unplug any boards just for safety so no errant voltage messes anything up. Careful inverter carries high voltage too.

[freakaftr8]

Re: Samsung LN52A750R1FXZA Turning on and off

Usually if the tcon were at fault, when you removed the LVDS cable that goes from the main board, that flat white ribbon like I mentioned earlier , the TV would stay on if the tcon were at fault.

So right now this is looking more or less like a main board failure.

[powerblackout]

Re: Samsung LN52A750R1FXZA Turning on and off

Ok, lets try unplug inverter and see if it quits cycling, always unplug tv before unplug any boards just for safety so no errant voltage messes anything up. Careful inverter carries high voltage too.

Sorry, what is the inverter board on this, the two pcbs on the sides of the TV?

[freakaftr8]

Re: Samsung LN52A750R1FXZA Turning on and off

Your inverter is fine you are not getting an image when the back lights come on. If your inverter or your bulbs behind the panel were at fault you would still receive an image on the screen after the back lights come on after the Samsung Chime.

I'm looking all over the Internet for a clear photo of your main board, can't find one, can you take a clear photo of both the front and back of your main board?

This may be a failure of C102 on mainboard if it has one.

[powerblackout]

Re: Samsung LN52A750R1FXZA Turning on and off

Are there another more ways to ensure it's the main board?

[nomoresonys]

Re: Samsung LN52A750R1FXZA Turning on and off

My bad, I read the other post wrong, so unplugging tcon made no difference=tcon probably ok.

[freakaftr8]

Re: Samsung LN52A750R1FXZA Turning on and off

Are there another more ways to ensure it's the main board?

Grab a hairdryer. Heat up the mainboard. All over it especially concentrating on the 2 processors and the various ram modules inside the white line area.

[powerblackout]

Re: Samsung LN52A750R1FXZA Turning on and off

Does anyone know if the various main board models for this TV are interchangable?

My part says: bn94-01708C
Part on ebay says it works with my model TV but is BN41-00995C on ebay.

Here's an ebay listing https://www.ebay.com/itm/Samsung-BN4...gAAOSwPpZaFCua

[nomoresonys]

Re: Samsung LN52A750R1FXZA Turning on and off

https://www.ebay.com/itm/Samsung-BN4...gAAOSwPpZaFCua took a quick look on ebay one there for 26 +9 shipping, always check all numbers to make sure you get a match.

[budm]

Re: Samsung LN52A750R1FXZA Turning on and off

Here is what SJ has about your board and the substitute board:
http://www.shopjimmy.com/samsung-bn9...a750r1fxza.htm

[nomoresonys]

Re: Samsung LN52A750R1FXZA Turning on and off

http://www.shopjimmy.com/samsung-bn9...a750r1fxza.htm
check lower right for interchange.

[nomoresonys]

Re: Samsung LN52A750R1FXZA Turning on and off

https://www.ebay.com/itm/Samsung-BN4...gAAOSwPpZaFCua took a quick look on ebay one there for 26 +9 shipping, always check all numbers to make sure you get a match.

Appears to be a match.

[nomoresonys]

Re: Samsung LN52A750R1FXZA Turning on and off

Too bad you cant do a factory reset or a firmware reapply in this one, might not have helped tho.

[cliff_hootarski]

Re: Samsung LN52A750R1FXZA Turning on and off

PTS electronics has a "repair and return" for that board.

I'd try to see if you have a C102 on the back side of the mainboard, as this cap has been known to cause power cycling.

[freakaftr8]

Re: Samsung LN52A750R1FXZA Turning on and off

It's probably a processor timeout issue. It's looking for a signal or certain function call out it's not receiving it so resets itself thinking that this is going to be the fix. A lot of times it can just be a BGA soldering problem on the processor ram modules that's why I mentioned to grab a hairdryer heating up the board up a little bit.

C102 failure Doesn't allow some circuit voltages to come up for the processor to operate properly. More sometimes introduces crosstalk in the voltages