On  0, chris <cb@mythtech.net> wrote:

> Double check you SCSI chain for proper termination. If it isn't right, 
> the Mac can get hung trying to find the devices and it may not get as far 
> as showing a flashing ? disk. And, try disconnecting the internal hard 
> drive as it may be mucking things up (if it is, it will at least get to 
> the ? floppy looking for a boot disk)

No floppy or HD is attached.
 
> Also, check your RAM. Try reseating it, and/or swapping it. Bad RAM or 
> marginal RAM can also cause it to hang during the memory test. Usually 
> bad RAM will cause it to report a sad mac or chimes of doom (depending on 
> which mac), but if it is marginal ram, it may just hang during the ram 
> test instead.

Sometimes, this chimes of doom plays. Not all times.

There are two DRAM SIMM slots empty. But it was working fine because there is the onboard RAM. What if the onboard RAM is bad?

Thank you for helping.