GNR TS902W no power , help please

[lcdcaps1]

Hi

I need some help from this magnificent community please.

I have an 19" WXGA TS902W LCD Monitor made by GNR has no power
no front light, nothing

I have checked the power outlet and cable, fuses all good.

I have checked the caps on both boards including the no signs of bulging

There are no burn marks nothing on the boards

The power board is made By Delta electronics and model number is
DAC-12M034.

I have seen that this power supply is used in other monitors
If some one has the schematic for this board, then please share.


I know I can buy a used board and replace but would prefer to fix this Myself


There is no voltage on the pins that connector connects to on the board
There is mains voltage coming in


Please can some one help me
I will appreciate it very very much

Many Thanks in advance

[lcdcaps1]

Re: GNR TS902W no power , help please

Bump

[rddube]

Re: GNR TS902W no power , help please

Ok, it would help if you posted clear photos of the power supply board.

[lcdcaps1]

Re: GNR TS902W no power , help please

The power board seems like it is used in other devices
I googled the power board model number

Please can some one help me diagnose this

[lcdcaps1]

Re: GNR TS902W no power , help please

Attached Image of My board
Taken from google

Looks the same
I don't see any burn marks or burnt components

checked the fuses
all ok

[rddube]

Re: GNR TS902W no power , help please

Attached Image of My board
Taken from google

Looks the same
I don't see any burn marks or burnt components

checked the fuses
all ok

No we can't do much with a photo of another board taken from Google. We actually need the photos of YOUR board, both sides.

Which fuses did you check, please mark them on the photos you will upload.

[lcdcaps1]

Re: GNR TS902W no power , help please

Tested all the fuses marked f on the pcb
Also checked the smd 0 fuses

Will appreciate anyones help with uploaded image
Please.
Many thanks in advance

[rddube]

Re: GNR TS902W no power , help please

So are you going to post the photos of your board? Can't help without them.

[lcdcaps1]

Re: GNR TS902W no power , help please

I posted a photo of the board

[budm]

Re: GNR TS902W no power , help please

So what DC Voltage do you have between the two legs of the main filter cap (120uf 420V)? Be real careful not to touch anything in the hot side.
We also need the straight shot pictures of the top and bottom side of YOUR board.
What is your country AC line Voltage?
What is revision of your board?
The one you show is REV 02A.

[momaka]

Re: GNR TS902W no power , help please

Probably need to replace the small "start-up" cap on the power supply board.

After checking the voltage across the primary cap as budm suggested above, check the voltage on the output of the power supply. Looks like there are 3 output voltages: 3.3V, 5V, and 12V. Most likely, the 5V and 12V should always be ON, as long as the PSU is plugged in. Posting pictures of your board (top and bottom/solder side) would be helpful to give you more troubleshooting suggestions, especially if they are bigger and better-focused than the one you posted from Google.

[lcdcaps1]

Re: GNR TS902W no power , help please

thanks for the response
what would be the correct voltage on the startup cap
also there is no output voltage at all

[rddube]

Re: GNR TS902W no power , help please

Should be around 160V DC if you are in North America, double that if you are in Europe. It would help a lot if you posted high resolution photos of your boards, both sides.

[momaka]

Re: GNR TS902W no power , help please

what would be the correct voltage on the startup cap

There is no "universal" correct voltage for the start-up cap. It all depends on what PWM controller your board uses for the power supply section. You find the datasheet for it and see what is the minimum start-up voltage. If the start-up cap has less than that across it's terminals, there's something wrong with the circuit (or the cap itself).

In any case, just change the start-up cap first. It's the easiest route and ensures that this is no longer a potential problem (or the problem itself).

also there is no output voltage at all

Yes, that can be a symptom of a bad startup cap. Other possibilities are blown output rectifier, bad output caps, blown component on the primary.

Since you don't have an output voltage, try measuring the voltage across the big 400/450V primary-side capacitor. As rddube noted, you should get either around 160V *DC* if you're in North America (or any country with 110/120V AC) or two times that in countries with 220/230/240V AC. BE VERY CAREFUL when you measure that cap - you're dealing with LINE-connected components here. You don't want to touch primary-side components with your hands when the power supply is plugged in.

[lcdcaps1]

Re: GNR TS902W no power , help please

Hi
finally got round to fixing this
The measured DC voltage on the primary cap is 324V

[rddube]

Re: GNR TS902W no power , help please

Sorry for asking again, but can you post clear large photos of both sides of your power board, we can then help you diagnose the problem.

If you measure 324V on the big cap (be careful when measuring on the hot side of the power supply), are you in Europe?

[lcdcaps1]

Re: GNR TS902W no power , help please

Hi
Yes in EU-UK
240V AC

Stuck on what next to do
checked fuses and zero ohm resistors again

[lcdcaps1]

Re: GNR TS902W no power , help please

Attached are photos of My LCD Monitor Power board

[rddube]

Re: GNR TS902W no power , help please

As Momaka suggested, have you changed or checked the startup cap? Can't really tell from the photos but it looks a bit bulged?

Also, when you say there are no output voltages voltages, what are you using for ground for checking? You can't use the same ground as on the hot side of the power supply (do you see the line separating both sides of the PSU) ? Use a ground on the cold side of the PSU and measure the voltages that are on the connector (they are printed on the circuit board)....do you get anything?

[lcdcaps1]

Re: GNR TS902W no power , help please

Hi
Thanks for the reply
I checked the startup cap and got 324V
I did not change
It looks flat, i just checked

I checked all the voltages on the connector using the ground pin but nothing
i checked again using a screw hole, also nothing