How do I troubleshoot starter problems in my Audi 80?

I recently bought a used Audi 80 and have been having trouble starting the engine. It cranks but doesn't fully turn over. Is there a specific approach I should take to diagnose and fix this issue?

First, check the starter itself for any signs of damage or wear. If it appears to be in good condition, the next step would be to test the battery voltage and connections to ensure they are providing enough power to the starter.

In some cases, a faulty ignition switch can also cause starter problems. You may want to have this component tested or replaced if necessary.

If all else fails, it may be necessary to take your Audi 80 to a certified mechanic for further diagnosis and repair. They will have access to specialized tools and knowledge that can help pinpoint the specific issue.