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Old 10-06-2011, 01:59 AM   #1
manyhobbies
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Thumbs up Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Hello

New to the forum. I search for a few hours and found lots of info....but none on this model.....so here it goes.

Was given a Gateway Model LP1925 which has the 2 seconds to black problem. The image is visible with a flashlight. The power light goes to amber without the computer hooked up. (I believe it stays green with the computer hooked up….can’t remember)

I don’t see any visible bulging caps.

All four lamps light and then go out after the ~2 seconds. (tried one lamp at a time) Same thing happens with a known good lamp.

I believe the board number is: E116921 (I hate trying to find the correct board numbers with all of the different numbers on them!)

I hope I’ve given enough info….


Thank you,

Dan

Here are some pics using my cel.....I'll grab the better camera if better pics are needed.


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File Type: jpg DSC00075[1].jpg (254.4 KB, 150 views)
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Old 10-06-2011, 03:49 AM   #2
Rtech
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Default Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Please dont add photos in line,they cause can problems for many members.
Suggest you try measuring Resistance between the points circled on the two inverter transformers,readings should be within 3% of each other.
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Old 10-06-2011, 08:15 AM   #3
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Default Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Quote:
Originally Posted by Rtech View Post
Please dont add photos in line,they cause can problems for many members.
Suggest you try measuring Resistance between the points circled on the two inverter transformers,readings should be within 3% of each other.
If the transformers check within 3%
A CCFl can light and still cause 2 sec. To black
Looking at a picture and being able to tell where to place the probes is something difficult for me.
The set up on this inverter may be what is described as a series circuit, If that is the case you should do testing with known good pair of CCFLs.There is a possibility you may have more than 1 bad lamp.
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Old 10-06-2011, 08:38 AM   #4
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Thumbs up Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Quote:
Originally Posted by Rtech View Post
Please dont add photos in line,they cause can problems for many members.
Suggest you try measuring Resistance between the points circled on the two inverter transformers,readings should be within 3% of each other.
I read about the pics 'not being online' but didn't understand.... I see that I can't edit my post.....will/would a mod please fix this for me as I can't remove the embeded pics myself.

I'll check the inverter transformers resistance. Thanks!

Quote:
Originally Posted by alexanna View Post
If the transformers check within 3%
A CCFl can light and still cause 2 sec. To black
Looking at a picture and being able to tell where to place the probes is something difficult for me.
The set up on this inverter may be what is described as a series circuit, If that is the case you should do testing with known good pair of CCFLs.There is a possibility you may have more than 1 bad lamp.
Well....I only have one good CCFL....

If the lamps are in series, why would they light at all?

This is the feedback that I was looking for!

Thanks A LOT!

Regards,

Dan
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Old 10-06-2011, 08:44 AM   #5
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Thumbs up Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Quote:
Originally Posted by Rtech View Post
Please dont add photos in line,they cause can problems for many members.
Suggest you try measuring Resistance between the points circled on the two inverter transformers,readings should be within 3% of each other.
Well...I did the OHM reading on what appears to be the secondary windings and get .63 on both so they appear to be good.

What is the part number of this board? Is it the E116921 number?

On checking the bulbs, I'll take the known good bulb and add another one from this monitor.

Thanks again!

Dan
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Old 10-06-2011, 09:03 AM   #6
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Default Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Quote:
Originally Posted by manyhobbies View Post
I read about the pics 'not being online' but didn't understand.... I see that I can't edit my post.....will/would a mod please fix this for me as I can't remove the embeded pics myself.

I'll check the inverter transformers resistance. Thanks!



Well....I only have one good CCFL....

If the lamps are in series, why would they light at all?

This is the feedback that I was looking for!

Thanks A LOT!

Regards,

Dan
That is something I should not, and will not try to explain!
I just think of it as one of the mysteries of the universe.
I can just go by what we have tried here in the forum, and what has worked for me.
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Old 10-06-2011, 09:08 AM   #7
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Default Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Well....I checked all four bulbs with the known good one. All of them react the same.

The monitor powers up....with a low volume beep/noise....the bulbs come on....go off....come back on and then off. With the video cable hooked up, the power light stays blue....

I should add that the previous ower said that he could get the monitor to work once and a while by unplugging it and plugging it back in.

When I got the monitor it was appart. I checked the board.....resoldered the larger components and was able to use the monitor ~20 hours without it going black. Now it's back to it's old tricks and no amount of power cycling will bring it around.

Thanks!

Dan
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Old 10-06-2011, 09:10 AM   #8
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Default Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Quote:
Originally Posted by alexanna View Post
That is something I should not, and will not try to explain!
I just think of it as one of the mysteries of the universe.
I can just go by what we have tried here in the forum, and what has worked for me.
10-4 Understood.
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Old 10-07-2011, 11:36 AM   #9
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Question Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Have you guys concluded that my bulbs are bad on this monitor? I checked all four (one at a time) with a known good bulb and they still shut off. In my opinion, which may not mean much, but I don’t think all four bulbs would go bad at once….. I do have an inverter from the laptop that I got the known good bulb from…..I probably could wire that little bugger up (outside the laptop) and test my bulbs…..thoughts? I also could pull the bezel on the laptop and plug in the bulbs in that inverter.

Here are my thoughts….tell me where I’m going wrong. Since all four bulbs are doing the same thing the problem ‘might’ be in the circuit before it splits for the two sets of bulbs. Where….?? I don’t know… Also....the output transforumers secondary windings tested withing the 3% of each other.

I have a soldering iron and know how to use it. I can pull components and test them. I'm not real solid in understanding how each component works but am willing to learn and can follow directions.

I believe this monitor is worth fixing…..isn’t it a high end one? I don’t see to many problems posted about them.

What about the caps? No one suggested changing them. I’ve heard that they can be bad without budging and I don’t have anything but a multi meter for testing. Would it be worth replacing them?

Anyone out there have a working board they'd be willing to loan me? I know that might be a bit much to ask for someone with under 20 posts.....

Thanks for all of the help so far!

Regards,

Dan in MN
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Old 10-07-2011, 12:12 PM   #10
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Default Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Quote:
Originally Posted by Rtech View Post
Please dont add photos in line,they cause can problems for many members.
Suggest you try measuring Resistance between the points circled on the two inverter transformers,readings should be within 3% of each other.
They do? Thats a new one on me...
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Old 10-07-2011, 12:25 PM   #11
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Default Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Quote:
Originally Posted by manyhobbies View Post
Have you guys concluded that my bulbs are bad on this monitor? I checked all four (one at a time) with a known good bulb and they still shut off. In my opinion, which may not mean much, but I don’t think all four bulbs would go bad at once….. I do have an inverter from the laptop that I got the known good bulb from…..I probably could wire that little bugger up (outside the laptop) and test my bulbs…..thoughts? I also could pull the bezel on the laptop and plug in the bulbs in that inverter.

Here are my thoughts….tell me where I’m going wrong. Since all four bulbs are doing the same thing the problem ‘might’ be in the circuit before it splits for the two sets of bulbs. Where….?? I don’t know… Also....the output transforumers secondary windings tested withing the 3% of each other.

I have a soldering iron and know how to use it. I can pull components and test them. I'm not real solid in understanding how each component works but am willing to learn and can follow directions.

I believe this monitor is worth fixing…..isn’t it a high end one? I don’t see to many problems posted about them.

What about the caps? No one suggested changing them. I’ve heard that they can be bad without budging and I don’t have anything but a multi meter for testing. Would it be worth replacing them?

Anyone out there have a working board they'd be willing to loan me? I know that might be a bit much to ask for someone with under 20 posts.....

Thanks for all of the help so far!

Regards,

Dan in MN
For safety reasons the inverter will shut the CCFLs off if it sees an over or under voltage condition. When you did your test with one CCFL at a time the inverter was acting normally.
My suggestion was to have 2 bulbs from the monitor you are having problems with hooked up to the inverter, and then beg borrow or well you know! And then Use 2 known good CCFLs and try different combinations to see if you can get the backlights to stay on.
There is a possibility 2 of the upper or lower bulbs could be causing the 2 sec black.
Ideally if you had another panel with good lamps you could hook up all 4 CCFLs and see if they stay on.
[No disassembling the panel just plug in the CCFLs]

Last edited by alexanna; 10-07-2011 at 12:29 PM..
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Old 10-07-2011, 12:31 PM   #12
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Thumbs up Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Quote:
Originally Posted by alexanna View Post
For safety reasons the inverter will shut the CCFLs off if it sees an over or under voltage condition. When you did your test with one CCFL at a time the inverter was acting normally.
My suggestion was to have 2 bulbs from the monitor you are having problems with hooked up to the inverter, and then beg barrow or well you know! And then Use 2 known good CCFLs and try different combinations to see if you can get the backlights to stay on.
There is a possibility 2 of the upper or lower bulbs could be causing the 2 sec black.
Ideally if you had another panel with good lamps you could hook up all 4 CCFLs and see if they stay on.
[No disassembling the panel just plug in the CCFLs]
For the test I used two bulbs...but two plugs were empty.....I think I see where you are going with this..

I'll plug 3 bulbs in and put my known good one in the 4th plug. I belive this to be a better test.

Thanks!

Dan
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Old 10-07-2011, 12:46 PM   #13
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Thumbs up Solution found! Bad bulb!

Quote:
Originally Posted by manyhobbies View Post
For the test I used two bulbs...but two plugs were empty.....I think I see where you are going with this..

I'll plug 3 bulbs in and put my known good one in the 4th plug. I belive this to be a better test.

Thanks!

Dan
Well.....I don't know if the first bulb I left out and put in the known good one was bad. However, the monitor stays on! I'll try putting that bulb back in and see what happens. Funny too! It was on the first test I found the bad one!


YEP! It looks like I've found my bad 'egg' bulb! The monitor fails with all of the orginal bulbs but stays on with the known good bulb. Looks like it's time for a bulb replacement!

Thanks for all of your help guys!


Dan
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Old 10-07-2011, 12:57 PM   #14
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Default Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Quote:
Originally Posted by Topcat View Post
They do? Thats a new one on me...
The auto resize helps, but still on a 10 inch netbook, it is difficult. For other reasons, see my post

http://www.badcaps.net/forum/showpos...5&postcount=12
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Old 10-07-2011, 01:00 PM   #15
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Default Re: Solution found! Bad bulb!

Quote:
Originally Posted by manyhobbies View Post
Well.....I don't know if the first bulb I left out and put in the known good one was bad. However, the monitor stays on! I'll try putting that bulb back in and see what happens. Funny too! It was on the first test I found the bad one!


YEP! It looks like I've found my bad 'egg' bulb! The monitor fails with all of the orginal bulbs but stays on with the known good bulb. Looks like it's time for a bulb replacement!

Thanks for all of your help guys!


Dan
I guess that's a big thank you
Glad you found it
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Old 10-10-2011, 05:56 PM   #16
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Thumbs up Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Well....the monitor been working fairly well....I'll probably have to re-bulb it. Once and a while it does it's lights out move. A power cycle brings it back. Anyone have any luck with the bulbs that cost ~6.00 each?

Thanks!

Dan
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Old 07-23-2012, 03:14 PM   #17
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Default Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Gateway Model LP1925 2 seconds to black image is visible with a flashlight .I renew the bulbs and the caps.but my problem is not solve
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Old 07-23-2012, 03:19 PM   #18
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Default Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Quote:
Originally Posted by APOERA View Post
Gateway Model LP1925 2 seconds to black image is visible with a flashlight .I renew the bulbs and the caps.but my problem is not solve
2 seconds to black can be

a) bad caps
b) bad ccfls
c) bad ccfl wiring (especially the return wiring)
d) bad secondary windings on the inverter transformer

More details starting with post #19 at

http://www.badcaps.net/forum/showthread.php?t=10419

Also, see budm's Inverter tester using old CFL

http://www.badcaps.net/forum/showthread.php?t=19987
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Old 07-23-2012, 03:21 PM   #19
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Default Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Quote:
Originally Posted by APOERA View Post
Gateway Model LP1925 2 seconds to black image is visible with a flashlight .I renew the bulbs and the caps.but my problem is not solve
Ok - You need to read this if you have not already read it.
http://www.badcaps.net/forum/showthread.php?t=10419
Start at post 19

Test the inverter transformers - I can show you where if you post pictures.

We can help a lot more if you please post good clear pictures of the whole chassis, and then pictures of each board, front and back and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

Please do not post inline and offsite as they slow down the loading of pages.

Examples of what is needed
http://www.badcaps.net/forum/attachm...1&d=1290283049

http://www.badcaps.net/forum/attachm...7&d=1280167246


EDIT - Im getting better - ONLY 2 minutes late!!
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Old 11-28-2013, 04:55 PM   #20
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Default Re: Gateway Model LP1925 2 seconds to black image is visible with a flashlight

Hello, I have the same board monitor as the original poster on this topic. I have been reading over the information. While mine is having the similar issue it does not 2 second to black.

Some times actually a majority of times the monitor comes on and seems to function fine and will run for hours. It may randomly shut to black and with a flash light i can see screen. Power indicator light is still on. I have disassembled the unit inspected the caps visually and all appear ok. I am aware that you can not always go with the visual inspection.

Lastly the part I find odd is that the monitor has a function to switch between themes. Example game, TV, movie etc. Now if I push this button it is almost with 100% of the time it will go to black. I have also noticed on occasion that the monitor as a whole will seem to reduce in brightness only to return a few moments later or few minutes.

i tested the transformers one reads .635 the other reads .624 now my math may be off sense I am not 100% sure atm remember percentages on decimals but that should be with in 3% or am I wrong. Transformers Read
SPW-068 Rohs
Darfon 2041 902035

I am of the mind that my next area would be too test the bulbs....but the them button situations makes me wonder if it could be in the wire. It is because of my indecision and unknowing that I decided to seek the wisdom of those who might have a recommendation on the next logical step to take.
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