Gateway 2100

[Krankshaft]

Re: Gateway 2100

Did you already check the driver transistors?

They are P and N channel FETs to be more specific. The four SMD packages circled in the other pic.

Made by Alpha and Omega Semiconductor D408 and D405.

Set meter to diode check measure from gate to source reverse probes reading in only on direction means good. Same process from gate to drain.

[freelander]

Re: Gateway 2100

I have checked continuity and done the diode test for these already. I tabulated the results back a couple of pages now. I do get similar results between a 'good' board and a bad one but when I measure source-drain on diode test, I get a reading but then it climbs until it goes OL. Does this mean anything or is that normal?

[_rdm_]

Re: Gateway 2100

I have one of these monitors that recently had the OP problem. When it turned on the power light dimmed and the monitor never turned on. This made me think it had a power issue and some reading through this board led me to believe that replacing the caps would fix it.

After replacing all the caps on board but the big ones The monitor now nearly functions perfectly. The power led turns on and functions normally now, turning yellow when no input is detected etc. The only problem is the LCD panel powers off 1 second after turning it on.

There are 3 CCFLs connected together on the top and bottom of the panel for a total of 6.

I opened up the monitor and watched all the CCFLs while powering on. When I only have the bottom 3 plugged in only the middle one lights and then it powers off. If I only have the top 3 plugged in the same thing happens. When I plug all 6 in and run it they all light about half way, sometimes bits glow at the other end but the middle one tends to remain the least lit.

I am not sure if this is conclusive of either bad CCFL's since they are not fully lighting or a bad inverter because of the erratic nature of their lighting.

I really want to get this monitor working as I am quite interested in the project. I was wondering if anyone could offer some thoughts or ideas on how to go about testing further. I am a student in electrical engineering so I probably have access to the tools I would need. If it is the CCFL's I have already looked around for the specific part that is the CCFL's wired and bundled as is in the monitor. This item is probably not going to be found so I think i would have to wire up my own CCFL's.

[freelander]

Re: Gateway 2100

Welcome to the forum. A good place to start would be to post some pictures of the power supply and point out which caps you have replaced. If you have gotten to the point of seeing which bulbs are lighting, I am assuming that you checked the ends and don't see any signs of blown bulbs like dark ends. The most common failure that I have seen with this monitor after the crappy caps that they put in is blown CCFL bulbs and then the 4 FETs mentioned at the top of this page. You will need to look for their replacements at your favorite electronics supply place. AOD417=AOD405 and AOD484=AOD408.