I have a PM Beige G3 Rev. C Desktop, 266 Mhz running OS 9.1, with
288mb and a10gb Western Digital hard drive.

I've just solved a non working power supply fan issue via a PS swap out only to have another problem.

Now, as soon as the power chord is plugged into the back of the computer it starts up by itself with no keyboard (or anything else) attached. In addition hitting the shutdown button only causes the computer to restart via both keyobard and file menu. (Restart and sleep file menu commands work properly.)

I reset the cuda switch keeping it pressed for a few seconds, and zapped the Pram as well for as many as 5 chimes. I then plugged in the keyboard, monitor, and other peripherals. This appeared to temporarily solve the issue and the computer responded to the shutdown command and stayed shutdown (via the file menu), until I plugged in a SCSI drive and powered the drive on. This immediately caused the computer to start up all by itself.

Doing another cuda and Pram reset has returned the old problem: the computer starts up all by itself when the power chord is plugged in and restarts when both the powerkey and file menu buttons are activated.

The only way to shut the computer down now is to unplug the power chord. The computer has a working Pram battery as it shows the correct date even with the power turned off at the surge protector end.

Is the new PS responsible (since the old replaced PS did not behave in this way) or is something else the culprit? Do I need to reset anything else to for the power up/ down of the computer to work properly?

Thanks for any suggestions, others might have.