need help with a gateway lp2407/fpd2484

[PlainBill]

Re: need help with a gateway lp2407/fpd2484

Its connected and the power led is blue when I disconnect the cable the power led goes yelllow . If I reconnect it returns to blue .

OK, that tells me the graphics processor is recognizing the video signal. Now if we could figure out why it isn't turning the inverter on.

PlainBill

[chetreynolds]

Re: need help with a gateway lp2407/fpd2484

Its connected and the power led is blue when I disconnect the cable the power led goes yelllow . If I reconnect it returns to blue .

[Scenic]

Re: need help with a gateway lp2407/fpd2484

I have been told that some go directly into sleep mode.

Most cheaper / noname Monitors do that, or they only display the "no signal" message for about 3-5 seconds before going into sleep mode. Not really helpful for troubleshooting..

Samsung and LG for example keep the no signal box floating around on the screen pretty much forever. (at least all of them i've encountered so far)

[PlainBill]

Re: need help with a gateway lp2407/fpd2484

You are correct I was able to trace back to the micro proccessor pins 50 and 243

Good. Now let's not forget the obvious. Is the monitor hooked up to a signal source (computer)? MOST of the time if there is no video signal the monitor will display a 'No Video' message. Some (Dell) display a color bar pattern. I have been told that some go directly into sleep mode.

PlainBill

[chetreynolds]

Re: need help with a gateway lp2407/fpd2484

You are correct I was able to trace back to the micro proccessor pins 50 and 243

[alexanna]

Re: need help with a gateway lp2407/fpd2484

See if this work's.Looks like it's on page 13
Wow! I get to learn about monitors, and how to attatch a PDF.
Thank you

[jetadm123]

Re: need help with a gateway lp2407/fpd2484

I found that OZ9938 controller listed on an o2 micro site which is in a PDF.
I am unsure how to attach it.
It's showing pin 4 as the dim and pin 10 as on off ???

You can attach the PDF file using the "manage attachments" button. Same thing as attaching photos

[alexanna]

Re: need help with a gateway lp2407/fpd2484

Have you tried checking fuse F1 to the left of the wiring harness? Also, check mosfets Q1-Q4 for shorts.

I found that OZ9938 controller listed on an o2 micro site which is in a PDF.
I am unsure how to attach it.
It's showing pin 4 as the dim and pin 10 as on off ???

[jetadm123]

Re: need help with a gateway lp2407/fpd2484

Have you tried checking fuse F1 to the left of the wiring harness? Also, check mosfets Q1-Q4 for shorts.

[PlainBill]

Re: need help with a gateway lp2407/fpd2484

I dont see any flash when I turn it on and the screen is a complete blank.

the voltages at the input connector are
pin 1 26v pin 2 26v pin 3 0v pin 4 0v pin 5 5v pin 6 0v pin 7 0v pin 8 0v

The board has 2 oz9938 chips u1 and u2 which I assume are controllers .
The voltages on u1 are
pin 1 0v pin 2 5v pin 3 0v pin 4 0v pin 5 0v pin 6 0v pin 7 2v pin 8 0v
pin 9 0v pin 10 0v pin 11 .68 v pin 12 0v pin 13 5v pin 14 0v pin 15 0v pin 16 0v

This appears to trace back to the signal card. As closely as I can tell, pins 1&2 are 24V from the power supply, 3&4 are gnd, 5 is 5V from the power supply, 6 is gnd, 7 & 8 are brightness and backlight on which come from the signal card, passed through the power supply to the inverter.

PlainBill

[chetreynolds]

Re: need help with a gateway lp2407/fpd2484

I dont see any flash when I turn it on and the screen is a complete blank.

the voltages at the input connector are
pin 1 26v pin 2 26v pin 3 0v pin 4 0v pin 5 5v pin 6 0v pin 7 0v pin 8 0v

The board has 2 oz9938 chips u1 and u2 which I assume are controllers .
The voltages on u1 are
pin 1 0v pin 2 5v pin 3 0v pin 4 0v pin 5 0v pin 6 0v pin 7 2v pin 8 0v
pin 9 0v pin 10 0v pin 11 .68 v pin 12 0v pin 13 5v pin 14 0v pin 15 0v pin 16 0v

[jetadm123]

Re: need help with a gateway lp2407/fpd2484

Great!

1) We'll need some good focused photos of the inverter board.

2) When you press the on/off button, do you see a momentary flash like the backlights trying to start?

3) In a dim room with the monitor on and connected to a running computer, if you shine a flashlight against the screen, can you see see a faint image of the desktop?

[chetreynolds]

Re: need help with a gateway lp2407/fpd2484

You can definitly pat yourself on the back for getting me this far .I replaced regulator 605 now have 3.3 volts and 1.8 from 604 . The power led lights blue and the controls seem to work ok . Now I need to work on back light proplems . The screen is blank .

[jetadm123]

Re: need help with a gateway lp2407/fpd2484

Good work! Looks like U605 is bad, since we expect a 3.3V output. If you still have U604 out of circuit, you can check it with a 9V battery for 1.8V output. Be aware that you're testing U604 under no load conditon. You might consider replacing it anyway, since the part is low cost. Replace U601, since 3.5V is a little too high. Digikey.com has these parts.

[chetreynolds]

Re: need help with a gateway lp2407/fpd2484

Vin for 605 is 5v and I have 0 ohms from 605 v out to 604 vin .What a differnce age can make before I turned 75 I may have thought of this .

[jetadm123]

Re: need help with a gateway lp2407/fpd2484

601 as1117-33
602 az1084s-3.3
603 az1117d-1.8
604 az1117l-18
605 az117l.3.3

Interesting.....Normally, VIN is supplied using the 5V or the voltage output from another regulator. The expected output for U604 is 1.8V, but you have a VIN of 1.2V. You have a VOUT of 1.2V for U605. I wonder if VOUT of U605 is feeding VIN of U604? Can you verify this? Also, what is VIN for U605?

[chetreynolds]

Re: need help with a gateway lp2407/fpd2484

601 as1117-33
602 az1084s-3.3
603 az1117d-1.8
604 az1117l-18
605 az117l.3.3

[jetadm123]

Re: need help with a gateway lp2407/fpd2484

u601 3.5 v
u602 3.3 v
u603 1.8v
u604 0 v input pin 3 1.2 v removed the chip and the input is still 1.2v
u605 1.2 v

Please supply part numbers for U601-605

[chetreynolds]

Re: need help with a gateway lp2407/fpd2484

u601 3.5 v
u602 3.3 v
u603 1.8v
u604 0 v input pin 3 1.2 v removed the chip and the input is still 1.2v
u605 1.2 v

[retiredcaps]

Re: need help with a gateway lp2407/fpd2484

Agree. We normally see 1.8V, 2.5V, and/or 3.3V DC for voltage regulators.