Sorry to hear your button did not click anymore, and that the disassembly was destructive. Thanks for the warning that pressing the switch button too hard and too deep puts excess pressure on the internal switch.
I have the preproduction TS25 also. It has seen very little use, but the button does work fine.
Because the Aux have only one brightness, I usually just store the light on top of my refrigerator with Aux Off.
Yesterday I planned to go for an evening tailgating party, apres ski. I decided to bring the TS25, so I could use the Red Aux, on constantly, (I dont like blinking) to mark the tailgate.
I selected the Red Aux, charged up the battery to full, and then rather than worry about parasitic drain or switching the Aux off, I just did Physical Lockout. It worked great!
I actually like the simplicity of advancing Aux colors using 7C. And the charge indicator lights worked properly. Even the voltage indicator on the switch when first turned on, worked fine.
So I kind of like the Prototype TS25. It did what I wanted at the time. The only thing it will not do, is keep the Aux On for long periods when not in use. I dont mind. I dont need the Aux to be on for me to locate the light, I used one of my other flashlights to look around in my pack to find the TS25.
So overall, my TS25 preproduction model is useful for a few hours of Aux light use. It has earned a place in my car camping kit.
FWIW, I also have the TS25 Production model, and have it set up the same way, bright red Aux constant On, and head unscrewed half a turn for physical lockout.
The main difference is that the Production model has a dim Aux mode, but imo it is not very useful, as that mode is so dim as to be almost invisible… I think the Bright Aux mode is more useful, when used as a tailgate marker for a few hours…
imho, none of the aux options, of either model, is useful for leaving on 24/7 for months at a time…
but the TS25 has other benefits, it works great as a floody light for indoor distances, and has some really great High CRI main LEDs… the aux lights are just for short term entertainment, not location markers.
For a location marker, the TS25 has the Anduril 2 Beacon option (if you dont mind blinking lights), which will flash the main LEDs every few seconds, depending how the user chooses to set the timing.
the beacon uses the last used brightness of the main LEDs, or the memorized output.
To turn on beacon from off, do 3C (battery check), then 2C (thermal check), then 2C (Beacon). Buy default the beacon flashes about once every second. This can be changed with 1H, which adds time as you hold the button.