eMachine 19" HDMonitor LE1987

[adamnp]

Hello, I'm trying to repair a monitor for a friend and I'm hoping someone here can point me in the right direction. Here are the symptoms: The backlight will only stay on for 4-5 minutes before going out. Once the lamps turn off, I can get them to turn back on if I power cycle the monitor - but the lamps wont stay on as long as they did from a cold start. Normally just a few seconds after first failure. Also, before the lamps go out the screen will start to flicker. So far I have replaced all the capacitors on the inverter board except two: the 450v 100uF, and a 35v 150uF Lelon. None of the caps were blown or looked even slightly bloated before I replaced them.

I don't know much about electronics, but it seems to me like something is overheating (mosfets?). However, I see no discoloration on the board. The model number is: ILPI-021 - I will post pictures later this evening.

Thank you for your help.

[retiredcaps]

Re: eMachine 19" HDMonitor LE1987

If you turn down the brightness and contrast to 25/25, does it stay on longer than 5 minutes?

[adamnp]

Re: eMachine 19" HDMonitor LE1987

If you turn down the brightness and contrast to 25/25, does it stay on longer than 5 minutes?

Hi, I'm sorry it took so long for me to respond. I did what you suggested and turned the brightness and contrast down to 25 but it didn't seem to make much of a difference in the length of time the monitor stayed on. However, I went a step further and turned both down to zero and so far (after a couple hours) it has yet to turn itself off. I also discovered its an LED lit monitor and not a CCFL light I had assumed. I hope this information helps, and thanks again for your assistance.

[jetadm123]

Re: eMachine 19" HDMonitor LE1987

At this point, you'll need to post some good photos of the entire top and bottom of your board.

[retiredcaps]

Re: eMachine 19" HDMonitor LE1987

I also discovered its an LED lit monitor and not a CCFL light I had assumed.

LED. We will definitely need pics. Please use the manage attachment function for your pics (see my sig file).

[adamnp]

Re: eMachine 19" HDMonitor LE1987

I hope these pictures are to your liking. Let me know if you need close-ups of a component.

Thank you.

[alexanna]

Re: eMachine 19" HDMonitor LE1987

Are you sure you have a LED monitor, the connectors look the same as a LCD type.
The only reason I ask is there is another LED monitor being worked on in the forum, I can't tell for sure but it looks like that monitor is using a ribbon cable for the Lamps.
I haven't had the opportunity to look inside a LED monitor so I am just wondering

[jetadm123]

Re: eMachine 19" HDMonitor LE1987

I agree with alexanna. It looks like a ccfl power board complete with the inverter transformers and 4 ccfl outputs.

Also looks like you used general purpose caps instead of low-esr caps.

Could be a bad solder joint. Try checking for a thermal problem by taking a hair dryer and heating up parts of the board to see if you can accelerate the shutdown process. Hopefully, you can isolate an area and we can go from there.

[retiredcaps]

Re: eMachine 19" HDMonitor LE1987

Looks like a ccfl setup as jetadm123 and alexanna mentioned.

We have only seen 1 LED power/inverter board here.

[adamnp]

Re: eMachine 19" HDMonitor LE1987

I agree with alexanna. It looks like a ccfl power board complete with the inverter transformers and 4 ccfl outputs.

Oh, okay. The only reason I thought it was an LED backlit monitor was due to an "LED Mode: Day/Night" setting in the monitor config screen. I couldn't find much, if any, information about this monitor online.

Also looks like you used general purpose caps instead of low-esr caps.

Pardon my ignorance, but is this a potentially bad thing? Should I always use low-esr caps for inverter boards?

Could be a bad solder joint. Try checking for a thermal problem by taking a hair dryer and heating up parts of the board to see if you can accelerate the shutdown process. Hopefully, you can isolate an area and we can go from there.

I think what I'll do is leave the brightness and contrast at zero (where it has yet to shut itself off) and heat up a section of the board at a time, while being very careful not to melt it. Thanks!

[alexanna]

Re: eMachine 19" HDMonitor LE1987

If this indeed a CCFL monitor, and you do not have any spare good CCFLs to substitute.
You could try this; Make sure the metal framework of the panel has a good ground just in case to prevent a shock.
Have the brightness turned all the way up and within that first five minutes, gently tap the frame work on the ends where the CCFL wires attach to the bulbs. See if you can recreate or accelerate the flickering or the lamps turning off.

EDIT
I should have said tap on all four corners of the LCD

[adamnp]

Re: eMachine 19" HDMonitor LE1987

If this indeed a CCFL monitor, and you do not have any spare good CCFLs to substitute.
You could try this; Make sure the metal framework of the panel has a good ground just in case to prevent a shock.
Have the brightness turned all the way up and within that first five minutes, gently tap the frame work on the ends where the CCFL wires attach to the bulbs. See if you can recreate or accelerate the flickering or the lamps turning off.

EDIT
I should have said tap on all four corners of the LCD

I have confirmed that it is indeed a CCFL monitor. I'll give your suggestion a try this weekend and report back. Thank you!