Samsung 2232bw recaped and still nothing

[benobeno]

Re: Samsung 2232bw recaped and still nothing

That is not good news. It's time to search for a service manual or schematic. I am afraid that the problem is the processor chip has died.

PlainBill

So its not just the 5V regulator?

And what part is the processor chip? Is this still a easy and cheap fix?

bye

[PlainBill]

Re: Samsung 2232bw recaped and still nothing

So its not just the 5V regulator?

And what part is the processor chip? Is this still a easy and cheap fix?

bye

A little background: Your monitor could be considered a special purpose computer. It takes signals from the VGA and DVI inputs and displays them on the LCD screen. It also checks the two lines from the front panel and interprets them to make changes. AND it switches certain things on and off - the backlight, the display panel, and the power led.

All of this is done by the processor. I've circled it in the picture below.

As far as replacing it, it's a custom Samsung chip, so it's unlikely you would find replacements available. And there are a lot of pins to solder.

PlainBill

[benobeno]

Re: Samsung 2232bw recaped and still nothing

Hello

I have one more question.

So I am going to try to change the regulator and hope for the best, before I throw it away.

Can you please tell me what kind of a regulator that is? I only know that it is 5V. What more info do I need, so that I can teel the dude in the shop to give me the right one.

Thanks

Bye

[Agent24]

Re: Samsung 2232bw recaped and still nothing

Even if it doesn't work, you don't have to throw it away - you could sell it for parts!

[PlainBill]

Re: Samsung 2232bw recaped and still nothing

Hello

I have one more question.

So I am going to try to change the regulator and hope for the best, before I throw it away.

Can you please tell me what kind of a regulator that is? I only know that it is 5V. What more info do I need, so that I can teel the dude in the shop to give me the right one.

Thanks

Bye

I seriously doubt that changing the 5V regulator will make a difference, but I won't even pretend that I'm infallible. I'd ask for an AP1501-50K5. It is a 150Khz, 3A PWM Buck DC/DC Converter in a TO263-5L package. As closely as I can tell, that is the original manufacturer. If your supplier doesn't carry Anachip Corp parts, there are a number of other manufacturers that produce parts that are identical.

PlainBill

[poly25]

Re: Samsung 2232bw recaped and still nothing

Hello,

I have the same problem whith my samsung 2232BW the AP1501-50K whith HW2596-50c and I have the same problem - only blue led on no invertor start no display.
Some solutions please.

[retiredcaps]

Re: Samsung 2232bw recaped and still nothing

Some solutions please.

1) Start with post clear focused pictures of your boards using the manage attachments function and please do not post inline.

2) Do you have a multimeter?

3) Hookup a working computer with your favourite wallpaper to the lcd. If you shine a flashlight on the lcd, do you see the wallpaper?

[Agent24]

Re: Samsung 2232bw recaped and still nothing

I suggest he start his own thread. Posting in other threads just makes everything harder to follow.

[benobeno]

Re: Samsung 2232bw recaped and still nothing

Hello

It is some time ago since we have last talked about my samsung LCD , but no I have aquired a working signal board and the LCD is almost working perfectly, but...

Ok the situation is like this: when i turn the LCD on the picture shows for about a second or two and then the ccfl goes off, but the picture is still there in the dark.

But if the situation (red multimeter lead on the marked pin and the black lead on grounf bolt) is like on the picture attached the LCD is working normal. And it also works if only the red lead si touching the pin.

Can somebody tell me why is that so and what to do?

Thanks

Bye

[selldoor]

Re: Samsung 2232bw recaped and still nothing

I wouldnt "play" on that pin - could be 2000-3000 volts!!!!!!
Try resoldering it and all the joints on route to the lamp socket.

With the power off you could test the secondary resistance on each of the two transformers - should be within 3% .

[budm]

Re: Samsung 2232bw recaped and still nothing

You should make two test lamps to verify if you do have inverter problem or lamp problem:
https://www.badcaps.net/forum/showth...er+testing+cfl

Did you check the resistance of the high voltage winding of both transformer yet, check the power MOSFETs?

[benobeno]

Re: Samsung 2232bw recaped and still nothing

Hello

The resistance is 1.187 in the 2k mode, is that ok? The lamps are both working if i make the connection with a multimeter as described in the previous post.

[selldoor]

Re: Samsung 2232bw recaped and still nothing

Is that the resistance on BOTH transformers. Are any of your blue high voltage
caps in that area discoloured?

[benobeno]

Re: Samsung 2232bw recaped and still nothing

One has 1.187 an other 1.184. Both blue caps are blue as they should be.

[selldoor]

Re: Samsung 2232bw recaped and still nothing

Well they look ok - I dont know enough about circuits to comment further -
Could try tracing where the circuit goes from that blue cap and see if resistance differs
from the same tracing from the other transformer.
Could try swapping the lamp leads over if they are long enough and despite me saying dont play in that area , if you are courageous enough test to see if the problem moves.

Perhaps budm will come back with an idea.

[budm]

Re: Samsung 2232bw recaped and still nothing

Resistance are OK.
There are two Power MOSFETs 8-pin SMD in that inverter section. Can you get the P/N as printed on top so we can look for the pin out? We need to check the resustance between S pin and the D pin of those two MOSFETs.

[benobeno]

Re: Samsung 2232bw recaped and still nothing

stm8309
75h71

[Agent24]

Re: Samsung 2232bw recaped and still nothing

stm8309
75h71

Here's the datasheet

[benobeno]

Re: Samsung 2232bw recaped and still nothing

If i measured it corect there is no resistance between s and d pins.

[budm]

Re: Samsung 2232bw recaped and still nothing

OK then, next thing to do is to use test lamps otherwise you can be spending lots of time trying to narrow down where the problem is.
BTW, the DC voltage (around 16~19VDC) on cap C111 is always present, right?