Kangertech Subox Mini Kit - Dancing Resistance

[Wash]

As always, the usual "if it shouldn't be here, please move" disclaimer applies.

I've been having this issue with my subox kit (bought new in September 2015) for a couple of weeks now.

Every so often (i.e. this is an intermittent issue - I have not managed to tie it to a specific foregoing event), I will take a hit and suffer immensely because instead of vapor, I'd get smoke.
Check the screen on the mod and the resistance dances from the usual 0.5ohm (where I usually build my coils) to sometimes even 3 times as much! Sometimes I can actually see the resistance climbing in 0.1ohm increments - this is without the fire button being pressed...

What I have done so far:

- Checked and tightened the screws holding the coil onto the mini RBA plus deck. Issue persists.
- Tried another mod (eLeaf iStick TC60W). Issue persists, but not as much, for some reason.
- Swopped my twisted (2 strand) kanthal coil for a single strand coil and re-wicked. Was better for a while, but as of about 5 minutes ago, Issue persists.
- Tried cleaning the threads both on the tank and the mods. Issue persists.

Seems that (as far as I can figure) the problem lies with the tank - either:
- The threads on the 510 connector
- The pin in the connector
- The insulator between these two things
- Gunk build-up on the coil, maybe?

Any other ideas, hints, tips from the gurus on how to solve this? I'm getting a new tank next week, but I really don't want to bench old faithful...

 

[Stosta]

Wow that does seem to be a pretty bizzare issue @Wash !

I seem to recall this happening on mine once or twice, but nothing that a simple clean, or re-attaching of things didn't fix. I would agree that it seems to be a tank fault (shown by the same thing occurring on a different mod), but you also have tried everything I would have to solve it (unscrew and re-attach, clean, use different mods).

I can't see how anything except a build-up on the coil itself would lead to a problem of the resistance changing as opposed to it simply shorting. Sure someone hasn't snuck some SS into your Kanthal stash?!

 

[Wash]

Sure someone hasn't snuck some SS into your Kanthal stash?!

Pretty sure no-one has tampered with my stash. I have yet to try SS and don't have any lying around to be mistaken for kanthal. Apart from the twisted wire I made ages ago, my kanthal is still stored on the spools...

If the build-up on the coils changed the resistance, I could accept it. But the fact that the resistance visibly changes and then CHANGES BACK is just baffling...

 

[Raindance]

Pretty sure no-one has tampered with my stash. I have yet to try SS and don't have any lying around to be mistaken for kanthal. Apart from the twisted wire I made ages ago, my kanthal is still stored on the spools...

If the build-up on the coils changed the resistance, I could accept it. But the fact that the resistance visibly changes and then CHANGES BACK is just baffling...

Hi @Wash

The resistance increasing indicates a loss of conductivity. The pattern you describe, sounds like the type one would find when arcing is involved. Possibly check the RBA base to 510 pin (inside the base) connection, black buildup and scarring of the nickel finish should be evident. Could also be the 510 to mod connection although swapping mods and finding a repeat performance would be unlikely in this event.

Other than that, the coil fastening screws, 26 AWG wire and up can be tricky to fasten properly, if yours is that thin, try wrapping around the screw (180 deg) before fastening and cutting.

Seeing that you have been using this tank for a considerable period of time, I believe the RBA seating to the 510 pin and its threading to the base to be the most obvious cause.

Good luck and regards.

 

[BansheeZA]

What i have seen on older rba sections is the bottom center pin/airflow screw threads ware out and then the positive moves ever so slightly to touch the inside of the rba chamber. Just make sure the positive block on the rba is tight and the threads are fine

Sent from my LG-H850 using Tapatalk

 

[Wash]

I have noticed that the post on the deck is slightly loose. I'm guessing that to sort this out would involve either getting hold of a new mini RBA plus OR replacing the insulator.

Guess it's off to the "Who has stock" section...

 

[Raindance]

@Wash , Just hold the centre contact steady as below and fasten it again. Don't turn the bejesus out of it, just tight will do. The insulator could be faulty and after all this time it did give you good service but this quick fix could carry you through until a replacement is ready.

Regards

 

[Wash]

@Raindance, I just refilled the tank and figured "while I've got the thing apart, anyway..."

Gripped the centre pin with my fingers and applied a little torque. It turned easily until it snugged up against the insulator and I chickened out. I recon if it was THAT loose, it HAD to have been the gremlin in the works.

My 0.5-something ohm coil is now a 0.4-something ohm (if you can believe the kbox mini), but it stays there. So for now, it looks like everything is peachy again!

Thanks to everyone for the advice!