V12 powers on and off only with tray closed

Hi,

I hope somebody can hlep me in this. I've modded more than 100 pstwo v12, v13 and v14 with original infinity modchips (never with a clone, except if the costumer required that, e.g. Modbo). My experience with infinity mods has always being very good, never having "big" problems in terms of instalation or funcionality. On the V12 models I always install the NeoFix II and so far, luckly, only 1 console was returned with burned laser.......the fix was also fried when this happened.
Well, the problem that i came across yesterday was this......i received a V12 to install infinity. I tested the console b4 opening it and it was working ok. I installed the fix and the chip. 1st time i went to test the console and try to update the chip with the firmware, when i pressed the power the console turned on and off almost instantly. I received red light, green light (for a few miliseconds) and then red light again. I opened the console and i realised i had connected the ground wire on a wrong point (the point used on V14). So, i put the ground on the correct place, and tested the console again.
This time, the console turned on, i updated the firmware with 1.88 and programming was ok. So far, so good. I always test a backup game after programmning a chip and then, when i was going to test the backup the console made the same as b4.....red light, green, red again. What i noticed is, if i turn the console on with the tray opened, the console turns on and stays on until i close the tray. If i try to turn the power on with the tray closed......red, green, red light. So, i only get this behaviour with the tray closed. Since this never happened to me and i don't beleive it's a fuse (cause i think if it was a fuse the console would never turn on) what could be the cause of this?
Also, why was i able to program the chip and now the console does this?.....could it be a firmware problem, modchip, crossed wires?
I've checked things over and over and it seems that everything is ok. I hope somebody has any ideias so i can try them.
Thanks in advance.