eMachines Le1938-Need Help

[Addikt]

Hello everyone my name is Aaron. I am new to these forums and I am seeking some help.

I have common knowledge on circuitry, but I am far from experienced.

What I have is a eMachines Le1938 19" Widescreen LCD monitor. The problem I am having with the monitor is that it will display perfectly, then display no signal detected. The monitor is not powering on and off, it is simply losing signal. There is a pretty stand out hum coming from the inverter. I have disassembled the monitor and have the board out of it. I just have no idea what to look for.

Odd Note* When the monitor displays my desktop if I press any menu key on the side of the monitor it will hold the picture until I release it. When I release the button, it loses the signal again and begins to cycle display/no signal again.

Thanks in advance, Aaron.

In This picture I have highlighted the portion where I think the sound is being created from.


The Back Side of the board

[PlainBill]

Re: eMachines Le1938-Need Help

A few points:
1. In the future, don't post pictures inline. It causes problems for those who have a slow connection and irritates the rest of us.

2. The general composition of the picture is good, but we really need something closer to 2000 x 2000 pixels to see details.

3. There are no obvious bulging caps, but many manufacturers have learned how to make caps that fail without any obvious signs. What brand are these?

4. The symptoms point to a problem with the signal (logic) card or bad capacitors on the power supply, with the former being more likely.

PlainBill

[Addikt]

Re: eMachines Le1938-Need Help

All the caps appear to have "Su'scon" written on them. I apologize about the pictures.

Here are the larger pictures.

Back Side of Board

Front side of Board

[PlainBill]

Re: eMachines Le1938-Need Help

All the caps appear to have "Su'scon" written on them. I apologize about the pictures.

Here are the larger pictures.

Back Side of Board

Front side of Board

My brain cells aren't up to speed this morning. That was probably the cause of the strange omelette I served my wife at 6:00 AM.

Check the FAQ; Su'scon are on the 'Bad Caps - Replace on Sight' list. I suggest replacing them with low ESR name brand caps such as Panasonic FM, FC, or FR series; Nichicon, Rubycon, and United Chemicon have equivalent high quality low ESR types. Don't go down to Radio Shack for the replacements.

We prefer to have pictures hosted on site, not off site for several reasons. Use 'Manage Attachments' (below the text entry area) to attach them.

PlainBill

[Addikt]

Re: eMachines Le1938-Need Help

PlainBill I appreciate your help in advance.

Now if one of the capacitors or several of them were out together.
Would it cause my screen to display, and not display, display, and not display? It is not losing its power, it is simply losing its power to display. Also when it loses its display ( displays no signal found ) that is when the humm appears. When the screen is displaying, the humm goes away.

Also I have counted 8 capacitors on the board.

220 UF, 35V
47 UF, 25V
1000 UF, 10V
470 UF, 25V
680 UF, 25V
150 UF, 35V
100 UF, 450V
47 UF, 25V

Is there precautions I need to take if/when I go to remove them all?
Do you have a rough cost in your head for the following list? (Ball-Park)

Edit* I would like to replace them with something that will provide a long life. The monitor is a pretty nice display, I would like to hang on to it if I could.

[retiredcaps]

Re: eMachines Le1938-Need Help

Do you have a rough cost in your head for the following list? (Ball-Park)

Edit* I would like to replace them with something that will provide a long life.

If you are in the USA, it should cost around $10 including USPS 1st class shipping and you get the caps in about 2 business days.

See

https://www.badcaps.net/forum/showpo...8&postcount=87

[PlainBill]

Re: eMachines Le1938-Need Help

PlainBill I appreciate your help in advance.

Now if one of the capacitors or several of them were out together.
Would it cause my screen to display, and not display, display, and not display? It is not losing its power, it is simply losing its power to display. Also when it loses its display ( displays no signal found ) that is when the humm appears. When the screen is displaying, the humm goes away.

Also I have counted 8 capacitors on the board.

220 UF, 35V
47 UF, 25V
1000 UF, 10V
470 UF, 25V
680 UF, 25V
150 UF, 35V
100 UF, 450V
47 UF, 25V

Is there precautions I need to take if/when I go to remove them all?
Do you have a rough cost in your head for the following list? (Ball-Park)

Edit* I would like to replace them with something that will provide a long life. The monitor is a pretty nice display, I would like to hang on to it if I could.

You bring up a good point. The answer is 'It could'. One possible explanation is excessive ripple on the power line to the signal (logic) card.

An analogy would be if a customer brought a car in to a mechanic. The complaint was poor handling. Possible causes would be bad shocks, bad alignment, or tires out of round. The mechanic notices the tires are seriously under-inflated. The first step would be to properly inflate the tires and road test. It could be a simple, profitable fix - $5 for air and $100 for labor. If, on the other hand, the tires had been properly inflated it would be time to check other things.

If you had reported the caps were Nichicon HD series, I would have suggested checking voltage regulators on the signal card. One problem with that as the first step is you probably don't have the equipment (an oscilloscope) to check the power bus properly.

PlainBill

[momaka]

Re: eMachines Le1938-Need Help

Also I have counted 8 capacitors on the board.

If you do end up replacing the capacitors, the 100uF, 450v one can be left alone. Those fail very rarely.

[Addikt]

Re: eMachines Le1938-Need Help

If you do end up replacing the capacitors, the 100uF, 450v one can be left alone. Those fail very rarely.

My philosophy would be, if you want to do it the right way, do it the right way.

Since I am going to replace a potential 7 capacitors, I might as well do all eight of them. I am very interested in prolonging the life of the monitor. If it was a 15" CRT I wouldn't be as worried however, it is a 19" widescreen. Which isn't the best of the best anymore, but it makes me happy.

@PlainBill

Oscilloscope - sure don't.

I am following your words very closely. From your post count/age I am making an assumption that you are probably one of the most knowledgeable around. Once again, an assumption .

Could the pressing of any menu play into that? I stated previously when the screen is lit I can hold down any of the menu keys and it will hold the picture. As soon as I let go of it, it loses its signal.

When pressing any menu key, could that be altering the electrical path and perhaps changing the power on the inverter somewhere? So the capacitor(s) that are probably my problem are receiving that extra umph that they need to power the display.

Sorry for all the questions, every day is a learning day. I know for fact, I work in retail.

[Addikt]

Re: eMachines Le1938-Need Help

I am back at it again with this monitor. Upon further investigating, when I unplug the LCD (glass) the power light stays on, no hum, and my computer detects the monitor. Obviously I have just removed the LCD panel from the unit. So technically its recognizing the inverter and logic board only.

Ideas?

[PlainBill]

Re: eMachines Le1938-Need Help

I have a couple of questions. When the monitor fails, does anything happen other than the hum and the 'No Signal' display? Do the backlights and the power LED stay on?

The obvious difference is with the LCD panel disconnected the power supply has less load.

PlainBill

[Addikt]

Re: eMachines Le1938-Need Help

Nothing else happens, the power LED stays on and the screen displays the no signal screen until it briefly returns to displaying the computer's desktop.

[alexanna]

Re: eMachines Le1938-Need Help

I am back at it again with this monitor. Upon further investigating, when I unplug the LCD (glass) the power light stays on, no hum, and my computer detects the monitor. Obviously I have just removed the LCD panel from the unit. So technically its recognizing the inverter and logic board only.

Ideas?

Another question when you say you disconnect the monitors glass, is that the 30 pin ribbon cable and all of the CCFLs?

[PlainBill]

Re: eMachines Le1938-Need Help

Alexanna, like your signature. It's similar to my 'Three things to check to know if you are having a good day.'

1. When you first wake up, check your big toes. If there is a tag attached, it doesn't look like this is going to be a good day.

2. Check the obituary section of the paper. If you are mentioned, things are REALLY looking bad.

3. Go down to the Post Office. If your picture is on a 'Wanted' poster, you can be certain you are having a bad day.

PlainBill

[Addikt]

Re: eMachines Le1938-Need Help

Another question when you say you disconnect the monitors glass, is that the 30 pin ribbon cable and all of the CCFLs?

Correct, that is a complete removal of the LCD screen from the main unit.

[alexanna]

Re: eMachines Le1938-Need Help

Correct, that is a complete removal of the LCD screen from the main unit.

If you haven't already it's probably time to consider spending the 10 bucks on some good capacitors.
But there is one thing I would like you to try.
Try hooking everything up but the 30 pin ribbon to the LCD.Power on.
Dose the LCD recognize a signal?
What do the backlights do?
Can you turn the monitor on and off with power button?

[Lex]

Re: eMachines Le1938-Need Help

If you are in the USA, it should cost around $10 including USPS 1st class shipping and you get the caps in about 2 business days.

See

https://www.badcaps.net/forum/showpo...8&postcount=87

I need to order the capacitors for this monitor. Is there a kit at badcaps.net?

Thank you.

[PCBONEZ]

Re: eMachines Le1938-Need Help

No kits but you can order caps.
Despite hordes of people showing up with bad screens lately BCN was originally intended for motherboard issues so he probably does not stock all sizes needed for screens.
- You'll have to look to be sure.
https://www.badcaps.net/store/
.

[retiredcaps]

Re: eMachines Le1938-Need Help

I need to order the capacitors for this monitor. Is there a kit at badcaps.net?

From what I know, badcaps.net started for motherboards. Thus, you will not likely find a premade kit for lcds.

There are 3 reasons why you should make your own list.

1) It is often cheaper than buying something premade.

2) Manufacturers can and do make revisions to boards while keeping the same lcd model number. Premade kits might not match your board.

3) You get to choose your own caps as you might have preferences or want spares.

[Lex]

Re: eMachines Le1938-Need Help

Thanks for the info!