Emisar D18 - No power, does not turn on

So, the other month I received an Emisar D18 directly from Hank. The first thing I did was take 3 of my button-top Samsung 30Q cells out of my working Noctigon M43 light, unscrew the head of the D18, put the cells in, then screwed the head back on (the same way I would with my M43). Absolutely nothing happens, the button does nothing, not even a flash indicating power. I then fully charged the cells and tried again, same result.

I emailed Hank, who suggested that I might not be screwing the tube in tightly enough to make contact. So I try that, again the head shows zero signs of life. After telling him that alongside a short video that I took, he determined that the head might’ve got damaged during the shipment process, so he shipped me a replacement head as soon as I started shipping mine back to him.

I’ve received the replacement head today, and guess what, got the exact same results. Now, I’m starting to think the problem is myself but I’m simply left scratching my head in confusion.

I’ve done extra tests such as the following:

- Powering the D18 with my spare Wowtac-branded button-cell, after seeing it work momentarily in the M43 (doesn’t work)

- Putting three 30Q cells inside of the D18’s body, and touching the cells positive terminals onto the M43’s head (works momentarily).

- Taking the tail board and batteries out, screwing the D18 head in as tightly as possible then put the cells+board back in (doesn’t work)

  • Putting the 30Q cells all back into the M43 again (works)

Any ideas?

Does the light work if you hold a cell against the driver+, and connect the negative end of the cell to driver- using a bit of wire? If so it sounds like something isn’t make contact in / with the tube.

Dang, it looks like it might’ve been a tube problem all along!
I used a pair of test leads, one end of them are electrical-taped to the cell terminals, and then I just used my hands to hold the other end of the leads to the ring-contacts on the D18 head I got, and it works. That said, I then put the head back into the D18 body with cells inside and it once again lacks proper electrical contact.