I have a broken SGI Indigo I'd like to fix, but I have no idea where to start.
The most obvious problem is that shortly after power on - two seconds, maybe three - a noise starts coming from the internal speaker. The sound becomes louder and louder with every second. No startup chime, no output on serial console.
My initial thought was a broken power supply, but a PSU repair guy I've found claims that power supply is ok and voltages are correct and clean. He also claims that he tried to bend the "mainboard" - probably the CPU board - slightly and this sometimes leads to the startup chime.
Any suggestions are welcome. Thanks