DS Lite, top screen flashes then shuts off?

I've tested both the upper and lower screens in another system and they both work fine. When I hook up those same screens to the original mainboard again the top screen flashes and I get nothing at all from the lower screen and then it shuts off. I've tried a new wifi board as well but that didn't help. I also tried a new upper and lower screen but it's the same thing.

Any ideas?? Thanks in advance!

 

its the motherboard then, you any good at soldering?

 

Yeah, I'm quite good at soldering. What exactly needs to be done?

 

there 2 fuses on the main board 1 for charging 1 for power use a multi meter to test fuse if continuity is not there you will need to solder it to make a connection

 

I've already checked those, they're not the problem. What else can I check?

 

If the top screen is flashing then it is something to do with the connection of the bottom screen. The DS checks both screens are running at switch on, if the top screen is flashing then it is the bottom screen at fault.

Make sure that the cable is inserted far enough, thick part of the cable (dark brown) pushed in to be level with the white line marked on the circuit board. Also check the connector is not damaged