I'll begin with the full story on this machine. I just got it a couple weeks ago. It had not ran in several years, but I know it ran when it was last powered down. It came from the company I work at so I've been around it for many years.

I'm using single phase power in a home shop. I was able to rewire the spindle motor controls to use a VFD to convert the single phase power into 3 phase for the motor. Basically, I left the original motor contactors wired up like they were except I removed the three phase power leads to them. Now, I'm using the contactors to open and close contacts to control the VFD. Worked pretty well, and the original spindle control panel works just like it did originally. I did make sure to leave the L1 and L2 leads that feed the transformer in tact.

I did confirm that the transformer is getting single phase, 245VAC and the taps/jumpers are set up for that. Voltage going to the motherboard's power supply is 118VAC. When I first powered the machine up, the control screen displayed a CMOS battery low error, press F1 to continue. Obviously, the CMOS battery needed to be replaced. I had to remove the mother board to find the battery. It's a real time counter with a battery built in...I had never seen one, but I was able to find a replacement. You have to solder it in. I have NOT installed it yet. My plan was to reinstall the mother board and hook up a PS2 keyboard so that I could get into the BIOS to copy all of the settings before replacing the battery. While I had the motherboard out of the machine, I did accidentally slide it off a table and it dropped to the floor. It landed fairly flat and no damage could readily be detected. After reinstalling the motherboard, it now does nothing. The screen displays nothing, and the floppy drive does not light up like it's trying to boot up from it.

My first inclination is that, yeah, I damaged the motherboard when I dropped it. I just want to make sure before I buy a new one. I was wondering if there were any tests that I could do to confirm that it is the issue. I did confirm that the PC power supply was outputting 5VDC from red to black, and 12.5VDC from yellow to black. All 4 led's on the back plane come on. I'm assuming that it doesn't matter what slot I install the motherboard in? I'm also assuming that the motherboard gets power through the backplane? I couldn't find anywhere else to get power to it. I know the monitor is good because I saw it display stuff early on.

I was going to try installing the new CMOS battery that I've got, but I doubt that will make a difference.

Is there any other diagnostics that I can do on the motherboard? Is there anything else that might cause this issue? I found a motherboard at BPTparts for $600. Is there a better place to get one?