Blank screen with no beep, after powerboard is replaced.

[zbyang]

I know that "Blank Screen" was perhaps the most popular problem. I have read all previous postings and tried a few things. None seems to work. So I am seeking additional advices now:

Machine: Gateway 200ARC laptop, 1 GB memory (512x2).

About 7 month ago, I noticed that the power supply light is going in and out with the power cord in. If I wiggle the power input jack, the light will come back. The computer is otherwise running normal. Gradualy, it needed more and more "wiggling" and finally no wiggling will bring back the light. The computer was running fine on battery, but eventually the battery is drained out and no way to charge it. Since it was a backup laptop, I just let it sit there for the past 6 month or so.

Recently, I decided that I needed that backup laptop. So I got a new power converter daughterboard (about $70) and swapped the old one out. As expected, the power light came back on and the battery is getting charged. But unexpectly, the computer will not boot. The HD light will come on a brief moment, the CD will make noice about two times. The CPU fan stayed on. I can even turn on the wireless card light. The HD is humming. But no beep of any kind and no nothing on the LCD. I have tried the following, one thing at a time, but no luck sofar:

Hook up an external monitor;
replace the CMOS battery with a new one (and I tested it with multimeter and it does have power);
leaving the CMOS battery out while booting;
leaving the LCD out while booting (hoping for a beep);
leaving the LCD and keyboardout while booting;
changed the RAM from 1GB to its original 256X2 chips;
leaving the RAM out completly while booting;
putting the 512x2 Memory back in.
use the CMOS battery wire to short it out while the power is on (since I could not find any jumpers around it);

So far, none of them made any difference.

Does anyone see any possibility other than fried motherboard? The fact that it was working just fine until battery runs out seems to suggest that it should not be motherboard problem. But I could see any other possibilities. It is a lap top. So besides the Power converter board I just replaced, everything else is pretty much soldered to the motherboard.

Any suggestion would be greatly appreciated.

Z.

[zbyang]

Or, by the way, I have double checked all connections. (There is not a lot connection to check any way, for a laptop.)

[Chaky]

Have you tried booting without main battery? You didn't mention that combination.

It is possible that the battery is completely dead and that it is draining all of the juice that comes out of power supply, making one big short circuit.

You should also check the motherboard for blown/damaged capacitors.

Once, I had similar issue with one desktop long time ago. It was "collecting dust" for 9 months or so. At first it didn't boot at all. After couple of hours of trying and failing it did boot. Turned out that floppy controller was fried for no good reason. Probably some static discharge or whatever fried it. Maybe same thing happened to your mobo.