Gateway 19" Flash

[el3ctroded]

No idea what the model number is, the back is lost for now. I didn't take it apart but wanna put it back together working

Anyway, what I know: It generates 5V and 14.5V.
The 14.5V should be 12V.
It isn't the CCFLs, cause it won't work with 4 known good CCFLs
It flashes on when plugged in, then goes off. The power led flashes at the same moment the screen flashes, but goes out. After going out, it does nothing, even when pressing the power button.

None of the large caps are bad. Removed and tested them.
Haven't tested the smaller caps.

The secondaries on the transformers booth read 1.8k.

No bad diodes or FETs.

[el3ctroded]

Re: Gateway 19" Flash

Oh yeah, and on the video board, U401 puts out 3.3V and U402 puts out 1.8V

[jetadm123]

Re: Gateway 19" Flash

Try checking the two surface mount mosfets on the power board, U303 and U304 for shorts.

[retiredcaps]

Re: Gateway 19" Flash

None of the large caps are bad. Removed and tested them.
Haven't tested the smaller caps.

Did you test both capacitance and ESR on the caps? They look like Samxon GF series. If correct, they don't have the greatest reputation with forum members here.

I believe 14.5V DC is okay and will measure 12V DC once the backlight comes on and stays on (i.e. there is a load).

[el3ctroded]

Re: Gateway 19" Flash

U303 and 304 no shorts
I did test the capacitance and ESR. They were fine.

I checked the smaller caps, and esr doesn't check out. It's C109, next to the transformer with the HiPot Ok sticker (bottom right corner of transformer). Could that one be an issue? It's 33uF, 50V, and I don't have a 33uF at 50V. I have a 47uF 35v... Not sure if I could get by with that...

Edit: well, measured again, its esr is only a little high

[jetadm123]

Re: Gateway 19" Flash

U303 and 304 no shorts
I did test the capacitance and ESR. They were fine.

I checked the smaller caps, and esr doesn't check out. It's C109, next to the transformer with the HiPot Ok sticker (bottom right corner of transformer). Could that one be an issue? It's 33uF, 50V, and I don't have a 33uF at 50V. I have a 47uF 35v... Not sure if I could get by with that...

Edit: well, measured again, its esr is only a little high

The 33uf appears to be a cap for the startup circuit. Since you are getting the 5V and 14V outputs, that means the power supply portion is up and running and the caps are doing their job.

If you connect the monitor to a working computer and point a flashlight at an angle towards the LCD screen, do you see a faint image of the desktop? If yes, then the inverter circuit could be at fault.

[Rolin]

Re: Gateway 19" Flash

el3ctroded, I have a Gateway 19" with the same boards you posted - suspect it's the same monitor. I know this thread is old, but wondering if you ever found the problem. My 19" Gateway has a very similar problem - when plugged in the power LED quickly flashes then dead - power button does nothing.

Did you ever fix this one or did you give up on it?

[Scenic]

Re: Gateway 19" Flash

Flashing power LED suggests either a short somewhere (trying to start, runs into short, shuts down, repeat) or a bad startup cap (tries to start up but fails). Maybe a bad SMPS controller IC, but if that one dies, it's usually completely dead.

Do you hear any ticking noises coming from the PSU when the LED flashes?

[Rolin]

Re: Gateway 19" Flash

Thanks Scenic for your post. I have a thread already titled "Gateway FPD1950 NO POWER" https://www.badcaps.net/forum/showthread.php?t=19066

I think you're right, some sort of short on mine. When I plug in the monitor, the power LED quickly flashes (I probably shouldn't have said quickly flashes - it quickly flashed one time when the cord is plugged in), then dead - the button does nothing. This is probably a tough one to fix, and since el3ctroded never updated he probably gave up and moved on. Check out my thread and let me know if you have any ideas.