need help with a gateway lp2407/fpd2484

[chetreynolds]

Re: need help with a gateway lp2407/fpd2484

I have 5v at the output of d855 and 24v from d853

[PlainBill]

Re: need help with a gateway lp2407/fpd2484

I have 5v at the output of d855 and 24v from d853

OK, now why isn't it working??? Have you tried hooking up the signal (logic) card only to the power supply? Let's leave the LCD panel and the inverter disconnected for this test. If you still get 5V and 24V it's time to add loads (front panel to see if the LED comes on, etc.)

As an aside, the other power supply designs I have seen switch the PFC on when turning on the main supply. It appears they use a different design here. The PFC portion of the controller is set to turn on when the load increases to a certain point.

PlainBill

[chetreynolds]

Re: need help with a gateway lp2407/fpd2484

With the signal board connected I still have 5 and 24 volts I checked the out of the regulators on the signal board and measured 3.5 and 1.8 which is correct per the data sheets . connected the power switch strip no led .I removed the power switch to insure the ribbon connector was connected .The power switch is a strip that is glued to the front panel . It has a synapocs chip on it there is no mechanical switch .
I connected the inverter no change .

[PlainBill]

Re: need help with a gateway lp2407/fpd2484

I count 5 voltage regulators on the signal card - U601 and U603 near the right hand edge of the card, U602 near the lower edge toward the left; U605 above it and slightly to the left, U604 above U605. Using the DMM measure the voltage on each pin. 3.5V is not a standard output voltage.

PlainBill

[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.

[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

[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

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

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

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

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

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

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

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

[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

[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.

[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

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

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

[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