Samsung Syncmaster 2233RZ No power

[accesspoint2007]

Hi everyone,

I have a Samsung Syncmaster 2233RZ with no power. The power LED does not light up.

Power cable : OK
No visible Burnt component
No Blown Capacitor on the power board : Model IP60135A (image attached)

Can anybody please help me troubleshoot. Does anyone have a schematic diagram of this board?

Thanks!

 

[KeepItSimpleStupid]

Visually, I see a fuse by the input connector (brown cylindrical thing). Check the p/n of the transistor on the heat sink and try to check the transistor/FET. A possible diode looks popped near the end of the heat sink.

 

[accesspoint2007]

Thanks for your response.

>>>> Visually, I see a fuse by the input connector (brown cylindrical thing).

The Fuse (F101) is OK.


>>>>> Check the p/n of the transistor on the heat sink and try to check the transistor/FET.

transistor? The one atached to heatsink is IC101 and has 6pins.

>>>>>A possible diode looks popped near the end of the heat sink.

The three diodes close to IC101 (attached to the Heatsink) are all good. I'm not sure which diode your are referring to that looks popped up. If you are referring to BD101 (also close to IC101, in between ZD101 and ZD102), it does not seem to be a diode (symbol looks like an inductor, not the anode and cathode) but seems to be OK as there is continuity.


I just noticed that there is a continuous soft clicking sound close to the power input when the power cable is plugged in. Seems like coming from C101 or C102.

I also did not get any reading of 3.3V on CN3 where the power switch is connected

What do you think?

 

[KeepItSimpleStupid]

Did you test the diodes on the diode scale and get an open on one direction and <0.7 V in the opposite direction?

 

[accesspoint2007]

I tested all diodes using VOM with no supply voltage on the board. All diodes open on one direction and close on the opposite direction except for BD101 which is close on both directions.

 

[KeepItSimpleStupid]

BD101 looks like a Ferrite Bead and would be a short in both directions. Can you read a part number of the device attached to the heatsink?

 

[accesspoint2007]

It's DMO7652R

 

[BGAmodz]

Hi access point , try at first to power up the card and see if the big capacitor has a voltage on it , BE AWARE voltage should be approximately 300 V dc if using a 220 V line .

Visually, I see a fuse by the input connector (brown cylindrical thing). Check the p/n of the transistor on the heat sink and try to check the transistor/FET. A possible diode looks popped near the end of the heat sink.

BTW can you put the marking code of IC101 , my guess its the power IC

 

[accesspoint2007]

The capacitor has a voltage on it around 180VDC to 190VDC using 110V line. Yes I think IC101 (DMO7652R) is a power management IC. What do you mean by marking code?

 

[BGAmodz]

The capacitor has a voltage on it around 180VDC to 190VDC using 110V line. Yes I think IC101 (DMO7652R) is a power management IC. What do you mean by marking code?

Its is the name marked on the IC usually two letters followed by a 3 or 4 digit number . the one you got is also called PWM ic .

 

[accesspoint2007]

IC101 is DMO7652R. I already tested all diodes and seem to be OK. I've been trying to look for a datasheet for DMO7652R but I can't find any. Could it be that the IC is defective?

 

[BGAmodz]

IC101 is DMO7652R. I already tested all diodes and seems to be OK. I've been trying to look for a datasheet for DMO7652R but I can't find any. Could it be that the IC is defective?

If possible look for the datasheet of that ic and check its VCC , just to make sure the ic is having the required entry voltage , as for the output , i don't know if there is a mosfet around or it is integrated on the IC itself .

You can also make a quick shorts/opens check for the diodes and other semiconductors before and after the transformer , of course while the power supply is shut down and big cap discharged .

 

[accesspoint2007]

>>>>If possible look for the datasheet of that ic and check its VCC , just to make sure the ic is having the required entry voltage , as for the output , i don't know if there is a mosfet around or it is integrated on the IC itself .

I will keep looking for a data sheet..

>>>>>You can also make a quick shorts/opens check for the diodes and other semiconductors before and after the transformer , of course while the power supply is shut down and big cap discharged .[/quote]

I Already did that..

 

[Misterbenn]

Have you checked the capacitors? I've seen other Samsung monitors with this type of clicking noise and it was always a blown capacitor.

 

[BGAmodz]

IC101 is DMO7652R. I already tested all diodes and seem to be OK. I've been trying to look for a datasheet for DMO7652R but I can't find any. Could it be that the IC is defective?

That ic is the transition from primary side to secondary side , i you make sure it working , the fault can be found after that section starting from the transformer .
Maybe someone here can help you know that .

Good luck .

 

[accesspoint2007]

Thanks KeepItSimpleStupid and BGAmodz for your time and inputs. I will keep on trying to troubleshoot with all your inputs. Hopefully I can figure out the problem.

Have you checked the capacitors? I've seen other Samsung monitors with this type of clicking noise and it was always a blown capacitor.

I checked all capacitors but no sign of visual defects. I even pulled out the caps and were tested ok.

 

[vtech]

IC101 is DMO7652R. I already tested all diodes and seem to be OK. I've been trying to look for a datasheet for DMO7652R but I can't find any. Could it be that the IC is defective?

That one is a "Green Mode" power switch from Fairchild Semi; Add a "FS" suffix in front and here is the datasheet
https://www.fairchildsemi.com/ds/FS/FSDM07652RB.pdf

 

[accesspoint2007]

Thanks Vtech!

 

[accesspoint2007]

Here are the readings I got from the IC101 pins:

VCC to GND : 8V to 14V
VFB to VCC : (-4.5V -to -8.8V)
VFB to GND : 10V - 12V
VSTR to GND : 40V to 130V

 

[Nigel Goodwin]

I checked all capacitors but no sign of visual defects. I even pulled out the caps and were tested ok.

How did you test them?.