Not sure if you're already past this part...
The suction cup and red (usually red) cable to the side of the CRT is an integral part of the flyback transformer. If you wish to reuse your analog board and flyback transformer, do not damage that cable/connector/suction-cup.
(BTW, I can no longer find a source for new flyback transformers for the compact Macs. If anyone knows of a source, I'd love to hear about it. I don't need any now, but we don't want any new old stock of those old parts to end up at the recycler.)
As another poster wrote, there's a sort of spring clip inside a hole in the CRT under the suction cup. Typically, one very carefully inserts a flat head screw driver under the suction cup, slides it to the hole, uses it to press one side of the spring clip inward and then gently pull the suction cup up a little to get that side of the clip out of the hole. Repeat for other side of the clip and remove cable/suction-cup from CRT.
The suction cup and red (usually red) cable to the side of the CRT is an integral part of the flyback transformer. If you wish to reuse your analog board and flyback transformer, do not damage that cable/connector/suction-cup.
(BTW, I can no longer find a source for new flyback transformers for the compact Macs. If anyone knows of a source, I'd love to hear about it. I don't need any now, but we don't want any new old stock of those old parts to end up at the recycler.)
As another poster wrote, there's a sort of spring clip inside a hole in the CRT under the suction cup. Typically, one very carefully inserts a flat head screw driver under the suction cup, slides it to the hole, uses it to press one side of the spring clip inward and then gently pull the suction cup up a little to get that side of the clip out of the hole. Repeat for other side of the clip and remove cable/suction-cup from CRT.