Supermicro X9SCM-F 6 beeps

Just got a Supermicro X9SCM-F off ebay. Supposedly came out of a working system. I put in an E3-1260L and a single stick of RAM - HMT41GU7MFR8C - PB which is on the list of approved RAM. No peripherals plugged in. On boot, it beeps 6 times and does not repeat. The beeps are lower pitched than other error beeps but seem to be about the same length as a normal short beep. Nothing shows up on screen. If I let it run for a while, the heatsink does get warm to the touch, so something is happening. Interestingly, the IPMI heartbeat LED blinks but it is not visible on the network. As troubleshooting, I have cleared the CMOS by shorting JBT1 with no change. I also removed the CMOS battery to no effect. I reseated the RAM, tried it in all 4 slots, reseated the CPU, tried a different PSU and flipped off the board for good measure. Once again, nothing. I tried different RAM, but it throws the 5short+1long code for incompatible RAM. That makes me think the stick I have is good. I cannot get into the BIOS to check version or anything else. Any idea what the beep code could be or how to fix it? All of the threads I have come across have been unresolved. The only reference to 6 beeps I have found says corrupted BIOS but that makes no mention of the different tone.

Additional troubleshooting that I forgot to mention - plugging in fans as some systems I have worked with have not booted without them. I also tried plugging in a keyboard (both usb and ps/2) to no avail.

Further update for anyone experiencing this issue: I realized that the HMT41GU7MFR8C - PB RAM that I ordered is 1600mhz. The E3-1260L maxes out at 1333mhz. I have ordered a stick of M391B5273CH0-CH9 which should work. I will update the initial question once that is in.

No dice on new RAM. I also tried a new CPU to no avail. Bad motherboard? Not sure.