Tube crashed for CRT screen SE/30

Hej Thomas!

Unfortunately, a broken glass part of a CRT means that air will enter. As with all vacuum valves/tubes, no vacuum = a non-working component.

It is possible to replace a CRT, but all work inside a compact Mac is or can be dangerous because of the voltages involved. Charges can remain in some sections/components for a long time after the computer has been switched off and disconnected from the mains. Both high and mains/line (and even lower) voltage levels are dangerous. So, any repair work must be carried out by someone with the necessary expertise. You should be able to find more information through a web search for something like 'replace CRT Mac SE/30'.

I heartily agree with what Jan Hedlund has posted.

Breaking that little glass piece off the tube wrecks it. There is no repair, except to replace the tube.

The risk to you cannot be understated. The High Voltage stored in the tube and the FlyBack transformer and connected Big Red Wire attached to the side of the tube are the biggest threats, (even after the power has been off for months). Connecting that Voltage through your body (e.g., hand-to-hand) can stop your heart.

Also, bumping any high-vacuum tube while handling can cause the tube to implode, spraying fragments of glass everywhere. (Except that your old one no longer has a high vacuum, so it is no longer a risk from that.)