To be clear, do I need to have a guitar plugged in as I replace each tube? I pulled the tubes, followed directions twice and the fuse remained intact. As soon as I plugged a guitar in and powered up, it blew the fuse.

This is extremely helpful.  I recently purchased a MAZ 18 that I had zero issues with for a few practices and gigs.  All of the sudden I am having fuse issues.  This looks simple enough and easy to follow to get the troubleshooting process started without destroying your amp.

Amazing, the man who designed the amp takes us thru a troubleshooting routine ! Only Dr Z ! Thx Doc, simple stuff but essential for us weekend warriors!

I remember that Z !!! Zenith used it in the 60s in their signage, awesome Dr Z !!

The Mesa/Boogie sticker on the shelf behind Mike is a nice easter egg!

I think I've watched this 3 times now and finally committed it to memory. ;)

Super informative, and so incredibly kind of you to take the time to do this.  Much respect!!

Thanks again Doc!

Very informative and clear. Thanks so much.

Another great AMA, Doc! AMAzing!

Thank you.  That was very helpful.

Thank you Doc! Worked like a charm. Love my Dr. Z amp!

Awesome!! Love this and the deep dives. Im seriously looking at the Octal 6 head. Already have a Maz18Jr. head.

Thanks DR

Thanks for this, good for an amateur like me to have on hand.

Great video, easy to understand, thanks Doc

Great video.  Thanks for this.

Great info Doc! Thanks.

Thanks again Doc...I've learn a lot from you

To be able to troubleshoot your Dr Z amp at a gig on your phone is genius! Dr. Z is the man!