How to replace the HT Fuse

"All valve/tube amplifiers have potentially lethal voltages within.
If you are at all unsure of electronic repair, please take your amp to a
qualified amplifier repair technician."

Firstly locate the HT fuse holder (on the back of the amp next to the mains input)

Then using a screwdriver to rotate the internal barrel about 45 degrees anti-clockwise.

Once this is achieved the barrel should “pop” out, holding the HT fuse

If the fuse is “blown” then replace with the same specification fuse.

If the fuse keeps on failing, then take your amp to your nearest orange dealer who will be able to help.