I'd be happy to help, but there's got to be about a half dozen recent threads about A/C and compressors. Scan those and you'll find some possible causes.

More specificity is better when asking for help. What fuse did you replace? #8, or the external fuse holder, if any?

Have you looked at the wiring diagram? Or the fuse diagram? Do you have a voltmeter?

How long ago did it quit?

R12 or 134a isn't necessarily relevant to the compressor not engaging right away, but it may be relevant to whether the system has a charge and how you check it.