The TML product differed from the TM in that it had more of the "legacy" (hence the 'L') I/O interfaces exposed. That is, TML added headers on the board for Floppy Diskette and Firewire interfaces and it exposed VGA, Parallel and PS/2 Keyboard/Mouse ports on the back panel. To make room for these legacy ports, the DVI-I, Display Port, E-SATA and two USB 2.0 ports were removed from the back panel.
The easiest way to tell the difference is to look at the connectors included on the back panel.
Ok, all that said, let's discuss your issue. From your description, it sounds like a short has developed on one of the power rails. This could be something other than a board problem. Here is my suggestion: Take the board and power supply out of the chassis and place them on a isolated/grounded surface. Connect nothing to the board except the CPU, memory and power supply. Try powering on the board by touching pins 6 and 8 of the Front Panel Header at the same time with a small screwdriver (these are the red colored pins of this connector). If the results remain the same, then you are looking at a board or power supply problem. In this case, borrow and test with another power supply. If the problem remains, you will know it's the board...
Hope this helps,