Recently I bought three Ipox IP-3ETI23 mainboards (S370) with P3-933 CPU. According to the seller all were once taken out of running systems, so I hoped they would all just simply work.

When I first powered them on, all three greeted me with the same beeps: three long and then a alarming constant high/low sirene (with the long beeps still in background)
A simple CMOS-Reset cured two of the boards, but the third is still in a somewhat half-broken state: After the CPU identification it simply stops. The CPU itself works in one of the other boards and another CPU gives the same result.
I also tried: swapping the battery, no keyboard, other RAM, other RAM slot, other CPU-fan connector
Any ideas anybody?

BTW. I can reproduce the long beep + sirene-alarm by removing the RAM stick which i find strange. The long beeps are the missing memory, but why is this also causing the sirene?