Dell E172FPB - power supply board

[dodobird]

Hello,

I recently acquired a 17" Dell E172fbp that turns on for 1 second then goes black. Now I'm planning to use just the LCD screen for a homemade projector, so I don't care about the back light. I'm wondering if I can replace the built-in power supply board with something else, like a couple of walmart adapters or a computer power supply. This monitor has 2 circuits boards: one for power and one for the LCD. They are coupled by 10 pins. 2 pins are at 5V, 2 are at 3.3V, 4 are ground and the last two energize at 2.45V and 3.14V when I push the power button.

What do you think? Is it feasible? A circuit diagram would really help if anyone knows where I can get my hands on one.

Thanks for any input!

[PlainBill]

Re: Dell E172FPB - power supply board

Hello,

I recently acquired a 17" Dell E172fbp that turns on for 1 second then goes black. Now I'm planning to use just the LCD screen for a homemade projector, so I don't care about the back light. I'm wondering if I can replace the built-in power supply board with something else, like a couple of walmart adapters or a computer power supply. This monitor has 2 circuits boards: one for power and one for the LCD. They are coupled by 10 pins. 2 pins are at 5V, 2 are at 3.3V, 4 are ground and the last two energize at 2.45V and 3.14V when I push the power button.

What do you think? Is it feasible? A circuit diagram would really help if anyone knows where I can get my hands on one.

Thanks for any input!

Unfortunate nickname - the dodo is extinct.

It might be possible to find or build a power supply, but it's probably not necessary. I have a suggestion: Hook the monitor up to a working computer and allow the computer to boot. Odds are when you hit the power button on the monitor you will see the normal display for a few seconds, and the power indicator will remain on after the screen goes black. That is the symptom of either a bad inverter (part of the power supply board) or a bad CCFL. The pins you measured at 2.45V and 3.14V are almost certainly the inverter control line and the brightness control line.

As far as converting this to a projector - well, good luck. Disabling the inverter section of the power supply would be a good idea. Post pictures of both sides of the power supply board if you want suggestions on how to do this. (Odds are cutting one jumper is all that is required).

PlainBill

[JohnFDay67]

Re: Dell E172FPB - power supply board

I have the same problem and would also like to get a circuit diagram, any ideas???

[Toasty]

Re: Dell E172FPB - power supply board

JohnFDay67 >>I have the same problem and would also like to get a circuit diagram, any ideas???<<

Ready for some lengthy reading?

Click on -Search- in the page title up top ^ and type in: Dell E172*

Have fun!

[FIXITNOW]

Re: Dell E172FPB - power supply board

usuall parts are
2SC5707 farnell 1554597 in the inverter circuit bracking down replaced all 4 as others offten strested The monitor I had also had a blown soldered-in pico fuse.3 amp
resolder the transformers even if they look good

[dodobird]

Re: Dell E172FPB - power supply board

Hi,

About the nickname -- I just picked it randomly (sometimes you have to wonder what goes through your head... ) Here's a couple of pics of the power supply board. I've inverted the picture of the underside so it matches exactly with what you're looking at on the top side.

Any ideas on how to bypass inverter circuitry? I just need power to the pins on the left that go to the logic board.

On a side note, I think I can see what causes the failure: it looks like one of the transistors on the far right took a hit and melted a bit...

Also, if anyone can tell me if the logic board actually needs 5v AND 3.3v or if I can get away with just 5v (that's what my cheap old computer supply will give me in the worst case scenario).

Thanks for the help!

[PlainBill]

Re: Dell E172FPB - power supply board

I'm sure the logic board needs 3.3V. Certainly the inverter doesn't. As closely as I can tell, removing L701 will remove all power to the inverter. If you can give me the chip number for IC751 I can confirm it.

PlainBill

[PlainBill]

Re: Dell E172FPB - power supply board

I'm sure the logic board needs 3.3V. Certainly the inverter doesn't. As closely as I can tell, removing L701 will remove all power to the inverter. If you can give me the chip number for IC751 I can confirm it.

PlainBill

Don't bother with the IC number. Don't bother removing L701 - it'll be hard to unsolder. You can accomplish the same thing by removing PF751 - the fuse for the inverter.

PlainBill