Do you have a spare power supply unit for your 4000?
Do you have another CDROM unit you can test in your 4000?
Do you have a voltmeter and know how to use it? If so, set your voltmeter to DC Volts and test the voltage between yellow and blue wires. Use the red test probe to the yellow wire and the black probe to the blue wire where yellow should read +5V and blue is your system ground (0V). If you get less than 4.85V, you need to replace the PSU.
If you know for sure that the PSU is fine, replace the CDROM. If that powers up no problem, then your CDROM is near retirement. Better off having it replaced. You can also try that CDROM in another computer and see if that fails.
Hope this helps...
:-)
