Trying to repair a DSL that doesn't power on at all. I checked the fuses (f1 and 2) with a meter and they tested good. I know the battery is good. AC power socket is broken, so I can't test with AC. I took motherboard from a known working DSL, put it in the non-working. On power up, Green light came on, both screens briefly flashed and then turned off. I put a bottom screen from a known working unit it it and it did the same thing. Haven't tried replacing the top screen. I also took the motherboard from the broken unit, put it in a known working unit and it still did nothing. Again, the fuses tested good on it. The flashing screens and powerdown with the good board baffles me. I am hoping to not have to replace the motherboard. I would appreciate any guidance or advice on possible fixes.