It is a death chime. Could be a RAM/ROM Error. Open the case and check/reseat the RAM/ROM. Which ROM do you use? Rominator sometimes does not fit very well in the ROM slot.
Hi. Testing ram in SE/30 is a pita as it requires to fill 4 modules for each bank.
I moved ram to color classic which have banks of two simms and I was able to figure out the bad simm. So, yes, the issue has been a faulty simm.
Thank you