Editing VAXstation 3100 Troubleshooting Guide (section)

== Dead system or no video ==
Check the basics first: the video cable at both ends, that the monitor is on with its LED lit, and the brightness. Then check switch S3 on the back of the system box: down when the monitor is the console, up when a terminal on the printer port is the console (at 9600 baud).<ref name="mg21" />

DEC's isolation procedure disconnects one FRU at a time until the system powers up normally; the last FRU removed is the faulty one:<ref name="mg21" /><ref name="mgg1" />
# Power down, remove the cover, and disconnect the cable from the system module to the MSC module and the power cables to the drives. Power up. If the system now works, reconnect the MSC module, then the drives one at a time, to find the culprit.
# Power down, remove the drive mounting panel and take the graphics module off the system module. Without it there is no video, so set S3 up and use a terminal on the printer port, or watch the LEDs. Power up.
# Power down and remove the memory module. Power up.
# Replace the system module. If the system still does not power up, replace the power supply.
When fitting a replacement system module, move the Ethernet ID ROM across from the old one, with pin 1 (the notch) the same way round.<ref name="mg104" />