Samsung Syncmaster 245B Black screen and blue Power LED

[delight]

Hi all

i've read this post https://www.badcaps.net/forum/showth...?t=9343&page=1

I have the same problem like this user - stewart710
(The monitor powers on, the blue power led comes on, but there is no image displayed. I tried this with a DVI cable and VGA cable hooked up to my computer, no dice. The only thing I did notice is that my computer can detect the monitor and knows what resolutions it supports. Also after the computer goes to standby the blue Led on the monitor starts blinking. It comes back on when I wake the computer. This suggests that the lcd motherboard is functioning properly.)

I opened the case and cant see a faulty cap. Do you think it can be the resistor RB805, RB806 and RB807 which are burned? Many users write about the same problem like my one and solved it by changing this three resistors.

I dont have good knowledge at electrical components but i think to can repair it myself

Of course i can upload some pictures after work so u can take a look on the boards.

[Rtech]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

Have you a meter,to measure resistance ?? or can you borrow one ??You will also probably need a soldering iron and solder ??

[delight]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

Have you a meter,to measure resistance ?? or can you borrow one ??You will also probably need a soldering iron and solder ??

All available via friend at university

[alexanna]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

Hi all


I opened the case and cant see a faulty cap. Do you think it can be the resistor RB805, RB806 and RB807 which are burned? Many users write about the same problem like my one and solved it by changing this three resistors.

I dont have good knowledge at electrical components but i think to can repair it myself

Of course i can upload some pictures after work so u can take a look on the boards.

Well the older I get it gets harder to remember, but I fairly sure if the 67ohm resistors fail you will lose the standby 5volts, and that equals no power LED.
As Rtech suggests you will need a DVM
Pitcures would realy help!

[delight]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

Here are the pics.

[Rtech]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

Measure the resistane of the resistors and change as required....then should that not fix it, there are lots of other options.

[Perineum]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

It was those resistors for me. Replace them with 3W versions just because it's open now.

[pthyme]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

I found this thread searching by google.
It looked like the same issue and beasureing the three resistors showedthat one of them were burned.
I bought three new 5W 68 OHM resistors as 3W was not available (I think that the original were 1W) for 4 euro. and replaced all three now the monitor was opened any way.

The monitor is now working perfect!

THANK YOU to everybody for both the pictures and advices

Regards
Per

[hydafl]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

we stopped in at the local radio shack but they had none in stock, so I checked with MCM electronics but no luck there as well. I am very new to this. Are these wire wound or ??
the shack had 1/8 1/4 and 1/2 watt rated resistors but nothing in the 3 or 5 watt range. Im sure its something I havent put together in ratings.. Any help would be appreciated

[Esquive]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

Hello everybody, i have the same problem with the screen failing to get a signal. The resistance to change are the 3 adjacent red resistances right? Meanwhile my monitor has a second problem:

I'm running the monitor using DVI. When I switch to VGA the display makes a crackling sound. The same happens when I turn the brightness higher than 20%. The brighter the screen is, the louder and faster the sounds are. The sounds are clearly coming from the supply board.

Do you think changing the resistance ill solve that problem to? Or do you think there is something else broken?

Thanks in advance, regards, Eric

[Rtech]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

One problem at a time looks the best way to approach this,so if the resistors do need changing, then do that,and then move on to the other problem IF it still exists.

[Esquive]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

Ok thanks for your reply. I will post my progress on this.

[NEOFEAR]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

Yes i just had the same problem and i replaced those 3 resistors with ones from an old AC-Power adopters and it works now
Thanks guys! I didn't have no tester so i saved some money and time

[TechAMP]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

well..mine has the same symptom, the 5V st.by is working, but the other supply 24V & 5.2V are missing! What is the next step to solve the error!? Thanks a-lot!!

[PlainBill]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

well..mine has the same symptom, the 5V st.by is working, but the other supply 24V & 5.2V are missing! What is the next step to solve the error!? Thanks a-lot!!

At this point I have two options. I can go dig up pictures of the two different supplies used in your monitor, I can ask you to provide on, or I can give you a general answer. I chose the last.

Check the voltage at the PC_ON pin. It should be about 3.3 volts. Check the voltage across the large cap. Is it about 1.4 times the AC voltage in your home, or is it about 385 volts?

For further assistance at least give the model number of the power supply (starts with BN44-).

PlainBill

[TechAMP]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

The model number of the power supply is BN44-00173A. The Prim. DC-supply is ok, otherwise there 'll not be any 5V st.by- supply! I can also measure pulses around L801 & TB801S and the prim.side of TM801S (not at pin connected to RM814), and no pulses at sec.-side of this trans, that deliver the +5.3V & +24V DC! I need a schematic on this board if anybody could help me with that!!??

[PlainBill]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

The model number of the power supply is BN44-00173A. The Prim. DC-supply is ok, otherwise there 'll not be any 5V st.by- supply! I can also measure pulses around L801 & TB801S and the prim.side of TM801S (not at pin connected to RM814), and no pulses at sec.-side of this trans, that deliver the +5.3V & +24V DC! I need a schematic on this board if anybody could help me with that!!??

Three points:

1. We are not exchanging messages by cell phone. Proper spelling and punctuation is appreciated.

2. There is a partial schematic in one of the other threads. Use the search function.

3. If you are getting pulses at the primary of TM801S check CM802. That is a known failure point.

PlainBill

[TechAMP]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

Thank you mr. PlainBill.!
U're a genius...It was right. I changed CM802 (18n 630V with a 22n ) and it's working now!

[PlainBill]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

Thank you mr. PlainBill.!
U're a genius...It was right. I changed CM802 (18n 630V with a 22n ) and it's working now!

Don't thank me too much. Thank the other guy who spent hours finding the fault, then reported it.

PlainBill

[synergy]

Re: Samsung Syncmaster 245B Black screen and blue Power LED

Thank you to all who contributed to this thread I purchased 3 5W 68 OHM resisters off ebay swapped out the old ones and its working like a dream now.