I have a Lil' Kking S amp and I love it. But lately she's been popping fuses left and right.
So being that the amp has a lifetime warranty I contacted Wayne Jjones, the owner and amp builder, and asked when I could ship it back to him, seeking prior authorization. He never got back to me. And I've heard from several others he has done the same thing to them.
Beware of Headstongs customer service.
I'd take it to a good tech nearby and forego the warranty. Headstrong proudly builds these amps as direct modern builds of the originals, warts and all. It's one of the selling points of the amp. This leads to things like switched neutrals on the AC wiring--a practice which has since been abandoned in favor of safer wiring schemes. And the chassis safety ground connection is made via terminal strip fastened to a power supply transformer bolt instead of a dedicated ground--as is the usual safety practice these days.
They also poorly implement "improvements" like standby switches (placed directly after the rectifier in a practice called "hot switching" that will stress the rectifier leading to earlier failure), EL34 compatibility (completely failing to tie pins 1 and 8 of the sockets together), bias adjustment (making the pot accessible on the back panel like a normal tone adjustment but not limiting the range to safe operating levels for less technical users), added Mids pots (an afterthought hacked into the back panel).
There are also questionable build practices like using klock nuts to fasten the circuit board but on the fiberboard side instead of the metal side. This can and does lead to the nut coming loose and shorting out nearby components. The reverb tanks are also held to the cardboard backer with rubber bands. These age and fail in short order. The entire interior of the cabs are covered with adhesive overspray from the tolex application. There is no shielding on the cab to complete the shield on the open end of the chassis. Caps added to the power supply for the higher power models are also just left floating by their solder joints instead of just using the proper can cap.
All of these things can be corrected by a good tech for not much money, but they'll never be corrected by sending it back to the person that implemented these flaws in the first place.
For the price people pay I wish they'd correct these issues.
As for your fuse problem, more often than not it's a tube issue. There are a few troubleshooting steps you can take that may eliminate the need for the warranty return or visit to a tech.