Dell E153FPB Screen Flashes

[ilikemycomputer]

Hello All,

I have a Dell E153FPB monitor, that has a problem. When you plug the power cord in, the screen will not power on. Instead, the back light and green power light will breifly flash. This problem started a few days ago, and I'm not sure of the cause. The monitor is connected to a power strip which is unplugged when the computer is not in use; so I am sure that it has not been caused by a power surge.

I thought the monitor was toast, so I left it unplugged for at least a day. When I plugged it in last night just to 'try it out', it turned on as normal and functioned correctly. When I turned the monitor on this morning, the Windows splash screen appeared, but then the monitor started flashing again.

I attached a video of the monitor that I took on my cellphone, which might help.. (I zipped it because .WMVs are not allowed to be attached)

I have looked at the previous topic, and am not entirely sure if this problem applies to my monitor...

http : //www.badcaps . net/forum/showthread.php?t=3360


I just wanted to get a 'professional' opinion before I swapped out the fuse, which was the solution in the previous topic.

Thanks in Advanced,

ilikemycomputer

[PlainBill]

Re: Dell E153FPB Screen Flashes

Hello All,

I have a Dell E153FPB monitor, that has a problem. When you plug the power cord in, the screen will not power on. Instead, the back light and green power light will breifly flash. This problem started a few days ago, and I'm not sure of the cause. The monitor is connected to a power strip which is unplugged when the computer is not in use; so I am sure that it has not been caused by a power surge.

I thought the monitor was toast, so I left it unplugged for at least a day. When I plugged it in last night just to 'try it out', it turned on as normal and functioned correctly. When I turned the monitor on this morning, the Windows splash screen appeared, but then the monitor started flashing again.

I attached a video of the monitor that I took on my cellphone, which might help.. (I zipped it because .WMVs are not allowed to be attached)

I have looked at the previous topic, and am not entirely sure if this problem applies to my monitor...

http : //www.badcaps . net/forum/showthread.php?t=3360


I just wanted to get a 'professional' opinion before I swapped out the fuse, which was the solution in the previous topic.

Thanks in Advanced,

ilikemycomputer

Those symptoms indicate a shorted transistor in the inverter, NOT a fuse. I indicated the transistors to check in the other thread. Check them.

PlainBill

[ilikemycomputer]

Re: Dell E153FPB Screen Flashes

Those symptoms indicate a shorted transistor in the inverter, NOT a fuse. I indicated the transistors to check in the other thread. Check them.

Thanks for the post. I checked those transistors; all of them seemed to be fine. I checked a few more and found one that was acting weird. I highlighted it in green in the picture I attached; when I touched second pin and third pin (or the first pin) with the ohmmeter, the voltage shot up, and then it displayed '1', so I assume this is the shorted transistor that is giving me problems. Or is this pin not used....? All of the other transistors displayed a voltage in the 600s and were pretty similar.


Thanks Again,

ilikemycomputer

[PlainBill]

Re: Dell E153FPB Screen Flashes

Thanks for the post. I checked those transistors; all of them seemed to be fine. I checked a few more and found one that was acting weird. I highlighted it in green in the picture I attached; when I touched second pin and third pin (or the first pin) with the ohmmeter, the voltage shot up, and then it displayed '1', so I assume this is the shorted transistor that is giving me problems. Or is this pin not used....? All of the other transistors displayed a voltage in the 600s and were pretty similar.


Thanks Again,

ilikemycomputer

That transistor is a FET. It switches the power to Q759 and Q760. Q743 performs the same function for Q739 and Q740. These are the drivers for the transformers. Even if it were shorted, it wouldn't cause this problem.

Let's see if we can figure this out. The symptoms are of a power supply that is shutting down because the output current is too high. It EXACTLY matches the symptoms I had with a Dell E173FPb. The question is if your problem is the power supply, the logic board / LCD panel, or the inverter / CCFL.

Unsolder one end of PF751. That provides power to the inverter. Then try the monitor again. You won't be able to see anything, but if the power LED stays on, the load from the inverter is causing it to shut down.

PlainBill

[ilikemycomputer]

Re: Dell E153FPB Screen Flashes

I unsoldered one side of the PF751, and it did exactly as you stated. The power light remained lit, and the back light was off. Does this mean the inverter needs to be replaced, or just a transistor?

Thanks again for all of your help,

ilikemycomputer

[PlainBill]

Re: Dell E153FPB Screen Flashes

I unsoldered one side of the PF751, and it did exactly as you stated. The power light remained lit, and the back light was off. Does this mean the inverter needs to be replaced, or just a transistor?

That remains to be seen. Let's see if we can figure it out. Since it isn't a transistor, let's see if there is something funky about the rest of the inverter. The first step will be to resolder all the pins on the transformers I had outlined in blue on the picture. Then replace the fuse and try it.

If it still fails, try unsoldering Q743 and seeing if the backlights come on for a few seconds (they may be dimmer than normal). If the power LED flashes, go to step 3. If the power LED stays on, but the backlight goes off after a few seconds, replace Q743 and remove Q751. Try it again. If the power LED stays on, but the backlight goes off after a few seconds, the inverter is probably good.

Step 3 Leave Q743 out and also remove Q751 and try again. If the power LED still flashes, you probably have a bad power supply.

If the Power LED flashes only when Q743 is inserted, there is a problem with the inverter or CCFL on that side. If it flashes only when Q751 is inserted, the problem is on that side. To eliminate the CCFLs, swap the leads at the connector.

One point I would like to make. Unless you have very little room for a monitor, it probably is not cost effective to spend a lot of money trying to repair this. ($5.00 in parts would probably worth in.) 15" monitors are definitely 'yesterday'. Rather, pick up a dead 17" or 19" monitor from Freecycle or Craigslist and fix that. The 15" may be better as a parts donor or test jig.

Thanks again for all of your help,

ilikemycomputer

Just wait until you have to pay it forward.

PlainBill

[EGuevarae]

Re: Dell E153FPB Screen Flashes

Just wait until you have to pay it forward.

PlainBill

[ilikemycomputer]

Re: Dell E153FPB Screen Flashes

Ok, I unsoldered Q743. The power light remained green but the back-lights did not turn on at all. The results were no different when Q743 was in, and when it was out. Should I try removing Q751?

Thanks again,

ilikemycomputer

[PlainBill]

Re: Dell E153FPB Screen Flashes

Ok, I unsoldered Q743. The power light remained green but the back-lights did not turn on at all. The results were no different when Q743 was in, and when it was out. Should I try removing Q751?

Thanks again,

ilikemycomputer

Ah, you DID resolder PF751, correct?

PlainBill

[ilikemycomputer]

Re: Dell E153FPB Screen Flashes

Alright, I resoldered PF571, (I don't know how I missed that ) The back light turned on for afew seconds and shut off,the power light remained lit. I'll buy a new transistor online, and post back the results when I receive it and solder it in.

Thanks Again!

ilikemycomputer

[PlainBill]

Re: Dell E153FPB Screen Flashes

Alright, I resoldered PF571, (I don't know how I missed that ) The back light turned on for afew seconds and shut off,the power light remained lit. I'll buy a new transistor online, and post back the results when I receive it and solder it in.

Thanks Again!

ilikemycomputer

NO!! No!! No!! All you have done is prove that that section of the inverter may be overloading the power supply. It is almost certainly not the FET; it could be one of the bipolar transistors on that side, the transformer, a bad cap, possibly a bad CCFL, or even a power supply problem. Now replace Q743, remove Q751, and see if the power LED flashes. If it does, the problem is on the side switched by Q743. If it does not, and the backlights behave the same way they did as reported above, it could be a power supply problem.

PlainBill

[ilikemycomputer]

Re: Dell E153FPB Screen Flashes

One point I would like to make. Unless you have very little room for a monitor, it probably is not cost effective to spend a lot of money trying to repair this. ($5.00 in parts would probably worth in.) 15" monitors are definitely 'yesterday'. Rather, pick up a dead 17" or 19" monitor from Freecycle or Craigslist and fix that. The 15" may be better as a parts donor or test jig.

Well, I came up to the conclusion that I will probably just purchase a new monitor, rather than put money and time into my outdated one. Thanks again for all of your help.

ilikemycomputer

[EGuevarae]

Re: Dell E153FPB Screen Flashes

Well, I came up to the conclusion that I will probably just purchase a new monitor, rather than put money and time into my outdated one. Thanks again for all of your help.

ilikemycomputer

What would you do with your unit if you don't fix it?

[ilikemycomputer]

Re: Dell E153FPB Screen Flashes

What would you do with your unit if you don't fix it?

I repair computers on the side, so I will just keep it for parts.


I thought about it, and I'm going to give it one more shot. I really want to get this monitor working again...

[andrepalmer]

Re: Dell E153FPB Screen Flashes

Those symptoms indicate a shorted transistor in the inverter, NOT a fuse. I indicated the transistors to check in the other thread. Check them.

PlainBill

I have the same monitor the power led stays on display comes up for a few seconds then shut off
What u thing hinder it to stay power up
I was suggesting its bad cap.

[selldoor]

Re: Dell E153FPB Screen Flashes

I have the same monitor the power led stays on display comes up for a few seconds then shut off
What u thing hinder it to stay power up
I was suggesting its bad cap.

Could be many things - you need to read this guide by retiredcaps.
https://www.badcaps.net/forum/showthread.php?t=10419

Start at post19

[Lumberjack777]

Re: Dell E153FPB Screen Flashes

Could be many things - you need to read this guide by retiredcaps.
https://www.badcaps.net/forum/showthread.php?t=10419

Start at post19

Yes selldoor. Good advice. And when he gets to the inverter section he's going to find a shorted C5707 most likely. (circled in red)
We can go all through the diagnostics like they had to do earlier in this thread. But this is a variation of the BENQ board. We know these boards all too well by now. I checked online and found a cheap repair kit that handles international orders (Jamaica).
http://www.ebay.com/itm/REPAIR-KIT-2...item3355ff711b

You need to replace the 4 transistors circled in red. The 2 fets circled in green. Check or replace the fuse circled in blue. And resolder the pins from the inverter transformers circled in blue. That should fix you. Good luck.