Diagnosing EAX64905001

[pi3141592]

Hi All,

I am trying to diagnose a EAX64905001 power board. The back-light will not come on. I have tested the LEDs and they are fine.

From reading another post - if I short 3.5V and PWR_ON with a 1k resistor - these are voltages I get.

PIN --- OUTPUT
3.5V = 3.47v
24V = 24.7v
12V= 11.94v

If I need to test the LED+ and LED-. Do I need to short DRV_ON with 3.5V? (I'm guessing this stands for LED DRIVER.)

Many Thanks, J

[nomoresonys]

Re: Diagnosing EAX64905001

Yes, give it a shot, see if the backlights come on.

[nomoresonys]

Re: Diagnosing EAX64905001

Can try test #3 below, that will tell us if your getting the right voltages and proper signals from the mainboard too.

[neilc6]

Re: Diagnosing EAX64905001

32LN series? Probably bad backlights. How are you testing them? You can remove the panel and see if they flash or check this Shopjimmy video. DRV ON turns on the backlights. Make sure it goes high when you turn on the tv.

https://youtu.be/2pyuXwNkBMA

[R_J]

Re: Diagnosing EAX64905001

You can also check the voltage on P801-4 LED+, You need to monitor this voltage when the tv is first turned on. Then do the same check on P801-1.

[pi3141592]

Re: Diagnosing EAX64905001

Hi All,

Thanks for your replies. I've checked LED+(Pin4) and LED-(Pin1) on P801 when the DRV_ON is shorted to 3.5V and the voltages are in the mV range and jumping allover the place.

Anyone seen symptoms like this? is it likely the chip IC801(MAP3202) is faulty?

I have also tested the LEDs with a donor board and so I know they are good.

Many Thanks, J

[nomoresonys]

Re: Diagnosing EAX64905001

"If I need to test the LED+ and LED-. Do I need to short DRV_ON with 3.5V? (I'm guessing this stands for LED DRIVER.)" Yes, do it with 2 resistors pwr_on and drv_on both to 3.5 stndby, see if backlights come on and stay on if they do the powerboard and backlights are ok. Did you do it??

[nomoresonys]

Re: Diagnosing EAX64905001

We can't help if you don't do the tests requested, we don't have the tv in front of us.

[dick_barton]

Re: Diagnosing EAX64905001

What dc voltage do you have at these pins of the MAP3202

VCC Pin 2 =
EN Pin Pin 1 =
REF Pin 8 =

Readings given from an earlier post on this forum.

What dv voltage do you have at P802

[ngth82]

Re: Diagnosing EAX64905001

+1 to post #7 from nomoresonys.

You don't want to directly short pins together. A small value resistor (the through hole, legged kind) - ~10K to ~100K range should do just fine. The idea is to provide a pull-up voltage. Not much current runs through this at all so you don't need to worry about the IR drop across it.

[R_J]

Re: Diagnosing EAX64905001

The supply that gives you +24 volts, also provides the base voltage for the led's from D204, through L801, so you should have at least +60v on L801 when you have the PWR-ON forced on. (A 1K resistors is recomended) anything higher might not turn on the power supply causing you to think there is a PS problem when there is not.

Check J34 (should be +24v)
Check J14 (led base voltage)

[pi3141592]

Re: Diagnosing EAX64905001

Hi All,

I shorted PWR_ON and DRV_ON through a 1K resistor. Then I checked the voltages on MAP3202 and got the results below.

1 - EN 2.9V
2 - VCC 11.9V
3 - GATE ~0V
4 - GND 0V
5 - CS 0V
6 - RT 3V
7 - SYNC 0V
8 - REF 5V
9 - PWMO ~0V
10 - OVP 2.8V
11 - PWMI 4V
12 - COMP ~0V
13 - FBP 0.8V
14 - FBN 0V

I went ahead and touched up the solder on on all the pins. Put it back together and it all seems to be working now. Not sure if that actually made a difference or the act of me taking it apart and putting it back. Will see how long it lasts.

Well hopefully this tread may help someone else out.

Thanks all for your input.

J

[nomoresonys]

Re: Diagnosing EAX64905001

Good to hear, yep the solder joints should should be one of the first things looked at, lots of times a bad joint is easy to spot and if that's all that's wrong can save a lot of time wasted doing a bunch of other tests, just because they didn't check the simple junk first. (Karl Childers rules)

[litec systems]

Re: Diagnosing EAX64905001

32LN series?
https://youtu.be/2pyuXwNkBMA

Hi
Could you please help me diagnose my(EAX64905001) 32Ln5400. Psu too? If so should i open a new thread or you can help me Here ( so iv someone will find this page from Google he'll have more troubleshooting ideas at one post + maybe the above dear members might be able to help me too?
The issue is no standby voltage no matter if the mainboard is connected or not.
Basically the mosfet + its 1kv capacitor + a 2w resistor + the fuse blown up ( known issue on this set)
So I've replaced them with new ones, but didn't knew that I have to pay attention to the fact that its a plastic ( isolated) mosfet
So as I've solder it up, the fuse got blown right away.
It tooks me time to understand that. Then I've isolate the mosfet from the heatsink, and plugged it in.
Now the tv isn't blowing up the fuse or something, it looks like there is a power to the main cap and not on the secondary side( I'm little afraid to probe the mosfet to prevent a short if i accidentally move my hands
Anyway
Do you have an idea what it could be and how to fully diagnosing it?
I suspect the mosfet isn't compatible with the PS \ it's got bad after the short because I haven't isolated it\\ the mosfet ic.., how could I test the mosfet ic?
Do you suspect that something else fried on the PS?
Hope you'll be able to help me out with this issue
Thanks alot!! :-)

[dick_barton]

Re: Diagnosing EAX64905001

Do you have the screen label numbers eg Qxxxx, Cxxxx, Rxxxx and what was the original mosfet part number (printed on it) and what did you replace it with part number?
A picture is worth a thousand words so photo's of your boards would be helpful.

[litec systems]

Re: Diagnosing EAX64905001

Do you have the screen label numbers eg Qxxxx, Cxxxx, Rxxxx and what was the original mosfet part number (printed on it) and what did you replace it with part number?
A picture is worth a thousand words so photo's of your boards would be helpful.

Hi
Thanks so much for your reply! 🙏🙏😃
By "Screen label" you meant to the sticker on the chasis? If so I've attached a picture of it. ( it's says 32ln542z because it's a local model number) but it looks the same as the international \ USA models ( the difference is probably the 1080p vs 720p but according to the videos on YouTube, they're all build from the same boards, just different panels + firmwares)

About the Mosfets
The original one was MDF11N65B

And I've replaced it with an st 15NM65N
g408t v6 *
chn 150 *
* ( the "0" might be "o" lol ST uses special font that I'm not always identify the characters 😂😂😂

[nomoresonys]

Re: Diagnosing EAX64905001

Some of your solder joints look a little funky as well, maybe touch them up.

[litec systems]

Re: Diagnosing EAX64905001

Some of your solder joints look a little funky as well, maybe touch them up.

Hi
It's because It didn't worked ive tried on the solder joints and added more solder to it that's why It looks like that...

[nomoresonys]

Re: Diagnosing EAX64905001

[/url] https://www.google.com/search?q=exam...w=1280&bih=645

[nomoresonys]

Re: Diagnosing EAX64905001

More examples: https://learn.adafruit.com/adafruit-...ommon-problems