Yes the whole design is modular, so repairing it is a simple task.
Troubleshooting a build is normal, the more experience you have as a builder the fewer times you’ll need to go back and find the problem.
In this case you know you have a proven working design.
Just take your time, make notes on the schematics so you don’t need to repeat any voltage tests.
If you find something you aren’t sure about, put a note and a picture in the Forum.
It’ll help future builders.
Cheers,
Jim
PS get into a regular habit of following the same safety precautions, that will increase your comfort and safety.
