So after 2.5 years, or near enough, I discovered last night that the GH doesn't have any polarisation protection!
Don't put the batteries in the wrong way, holy fuck!
I'd go as far to say that this would explain the few instances of burnt out devices.
I was pretty baked and grabbed a battery from the charged stash, I have one battery which I've adjusted the wrapping on the negitive end - I picked up that one, but decided to use a different batt. The one I grabbed was sitting 180° from the other, and without looking I dropped it in the hopper. I did the back end up and decided to select a different temp, finding that the dial was really hard to turn, almost fixed in place. How strange I thought, has the unit just died? A lot of force got it twisting, so I tried some big turns back and forth to 'loosen up the mechanism'. I hear electrical noise but no LEDs light up, and I'm thinking maybe the battery is inverted, or the back end is properly stuffed. I click it on, and the back end starts heating up fast. It doesn't stay on, but it was continueing to heat up and I began to smell hot electronics, the body and back end were beginning to be seriously hot to touch and I was considering grabbing a rag to further handle it, but I madly rushed off the back end and removed a HOT battery from the device.
The back end was also super hot, so I left it to cool down. The smell subsided, and I reckon much longer and things would have been catastrophic.
The front end wasn't affected.
I thought I probably killed the device, and eventually tested it to find that it still works as per normal.
Whoops!
Don't burn your houses down.
Someone should take the design and components and bring it to a single PCB. The amount of general problems is one thing, but the safety spec is very questionable.
Sure it's user error, but it's clearly happened before
https://www.reddit.com/r/GrassHopperVape/comments/5481nl/my_grasshopper_almost_exploded_serious/
How tarnished are the back-end threads looking?
A bit of blue tack might be able to spruce it back to life.
Also check the threads on the body, the battery terminals and contacts and the chamber itself for residue