Wismec RX Gen3 Dual - odd resistance behavior

Discussion in 'Issues' started by k3rb3r05, Aug 13, 2019.

  1. k3rb3r05

    k3rb3r05 Member

    Joined:
    Aug 6, 2019
    Messages:
    32
    Likes Received:
    1
    Device: Wismec RX Gen3 Dual
    Hardware version: 1.00
    Firmware: 190624
    Profile set up: TC
    Coil: SS316L / 30 awg / 7 wraps / spaced / 2.5 ID
    # of coils: 1
    -----------------------
    PI Regulator: Disabled
    TCR: 125 (dry cotton test @ 410 F)
    Smart: Enabled / 10%
    -----------------------

    In AF, I have set (and locked) cold resistance at 1.050 (steam engine says coil is at 1.046 ohms and my ohm meter reads it at 1.05 ohms)

    Issues:

    1) If I remove atty and reinsert it, it goes into "Profile Selection" screen. 1 of 2 things will happen.
    a) If I let screen time out, I get to keep my resistance setting of 1.05. Screen displays live resistance but upon tapping fire button, resistance changes to 1.05
    b) If I tap the "Fire" button, I lose my resistance setting and it gets replaced by live resistance at that time (even though profile selection screen lists the resistance at 1.05)
    Figured this one out. It was due to smart and resistance being read outside the 10% range
    BUT
    Shouldn't pressing "fire" keep the settings?

    2) With cold resistance setting of 1.05, when I tap the fire button, screen shows the resistance jumping from 1.05 to current live resistance. The lowest I get is 1.18 but each subsequent fire tap will increase the initial jump to the current live resistance (1.05 -> 1.19, 1.05 -> 1.20, 1.05 -> 1.22, and so on).

    3) Catch 22. If I lock resistance to:
    a) 1.05 and set 2W (!!!) / 220 C (or 428 F) ceiling , as soon as I tap fire (or within a 1”-2”), I reach ceiling and beyond, ie 260 C (or 500 F).
    (Note: I get a weird spike of 760 C (or 1400 F) using the following: 1.05R/5W/180 ceiling)
    b) 1.15 and set 5W / 220 C, I never hit ceiling. Max temp reached is 170​

    Obviously, (b) produces far better flavor throughout the vape. (a) cuts off too soon resulting in nearly no flavor/vapor. Also, while in (b), if I remove and reinsert atty, it doesn’t go into profile selection screen.

    EDIT:
    Stock firmware version 1.02 reads resistance @ 1.13-1.15
     
    #1 k3rb3r05, Aug 13, 2019
    Last edited: Aug 14, 2019
  2. k3rb3r05

    k3rb3r05 Member

    Joined:
    Aug 6, 2019
    Messages:
    32
    Likes Received:
    1
    From an older thread in "issues"

    So, the problem isn't the firmware but my box reading resistance wrong? Both atomizer and mod box are brand new. So the lesson of this "ordeal" is to screw on a cold atomizer (which I had) but keep the resistance that the box reads it at and not what steam engine or my ohm reader says it is?

    PS: Tried same atomizer on my pico 75w and it reads considerably lower (0.07 ohms)
     
  3. k3rb3r05

    k3rb3r05 Member

    Joined:
    Aug 6, 2019
    Messages:
    32
    Likes Received:
    1
    In Advanced , there is a setting that rectifies aforementioned problem: Internal Resistance

    Right?

    That said, would something like this work? https://forum.evolvapor.com/topic/66031-510-999-pure-copper-mod-resistance-tools/

    Is anyone aware of an alternative diy contraption that would have the same result? Could a copper screw have the same effect? Say one from a hardware store. If it's not pure copper, does it matter? and If it does, is there a set value I could offset "internal resistance" by?
     
  4. tim_buktu

    tim_buktu Member

    Joined:
    Jul 7, 2018
    Messages:
    39
    Likes Received:
    8
    Hi,
    from my experiences with poor internal resitance (eVic Primo) caused by bad construction:
    see here: https://nfeteam.org/forum/threads/primo-v1-reading-coil-resistance-too-high.2605/

    You can easily build an zero-ohm-attomizer by yourself. I made it from an useless Cubis that I blocked with 6mm steel screw.
    This shortcut ist good enough to go into AF-Setting "internal resistance" and correct the readings (MOD's display) to the right value: zero.

    be careful: If your problem is similar to that I had with the Primo (ohm readings jumping arond the galaxy) this will NOT help and should not be done. If several values differ to much you have a hardware problem -> the MOD needs repair

    I hope this helps
     
    k3rb3r05 likes this.
  5. k3rb3r05

    k3rb3r05 Member

    Joined:
    Aug 6, 2019
    Messages:
    32
    Likes Received:
    1
    Thanks for pointing me in the right direction

    Other than my cold resistance being off (which i rectified increasing the internal resistance), my live resistance goes up and down by -0.03 to +0.03 difference from my cold resistance , when not being used but from what i understand from reading the forum, it is normal, especially if monitor is running
     
  6. tim_buktu

    tim_buktu Member

    Joined:
    Jul 7, 2018
    Messages:
    39
    Likes Received:
    8
    I would not use the device monitor. Just shotcut the 510connector anyhow and look at the resistance value on MODs display.
    This value should be stable around zero ohm, NOT jumping +/- 0,03 ohm. If you cannot get it stable and shortcut is quiet good, you may have an internel issue with bad connetions/groundings.
     
  7. tim_buktu

    tim_buktu Member

    Joined:
    Jul 7, 2018
    Messages:
    39
    Likes Received:
    8
    the Mod must be set to show the LIVE-resistance in one of its TC parameter fields of course :rolleyes:
    good luck
     
  8. k3rb3r05

    k3rb3r05 Member

    Joined:
    Aug 6, 2019
    Messages:
    32
    Likes Received:
    1
    Thanks. Seems I'll need it. I am fairly new to TC; just a month old baby. Eventually, I'll get to the bottom of this

    Thank god there is AF to compensate for manufacturer's lack of firmware options / information displayed AND forum members to assist new users
     
  9. tim_buktu

    tim_buktu Member

    Joined:
    Jul 7, 2018
    Messages:
    39
    Likes Received:
    8
    Tell me what is your location means country? If you are german we can easier talk in german forum.
     
  10. k3rb3r05

    k3rb3r05 Member

    Joined:
    Aug 6, 2019
    Messages:
    32
    Likes Received:
    1
    Greece. I can't speak german, but I can google translate.

    edit: fixed it somewhat. one of the ground screws was loose. behaves slightly better now that i tightened it.
     
    #10 k3rb3r05, Aug 21, 2019
    Last edited: Aug 21, 2019
  11. tim_buktu

    tim_buktu Member

    Joined:
    Jul 7, 2018
    Messages:
    39
    Likes Received:
    8
    Okay, no need to translate:)
    When you use SSL316 Wire that has a low TCR value, it is essential that you eventually existing internal problems with bad grounding connection getting fixed. Jumping resistance values of +/- 0.03 is way to much.
    When tightening the screws improved the behavior: are you now at a stable zero-ohm- shortcut on 510connector?

    From my experiences with with SSL316 I would even recommend a lower value for TCR about 90.
    For better and stable results I changed to using titanium wire. Its TCR is about 340-355 and you'll get a much better temperature control .
     
  12. k3rb3r05

    k3rb3r05 Member

    Joined:
    Aug 6, 2019
    Messages:
    32
    Likes Received:
    1
    rx gen3 dual is a very compact mod. I will eventually fix it by replacing the 510, but I don't have the tools for such precision work. Both the mod and the power tool(s) will need to be held in a vice, in order to add stability and control. For sure I need a right angle attachment (the mod has an 1cm lip on the battery side) and use a tiny cutting disk or grinding stone to work in that tiny space (edge of 510 is about 2cm away from that lip). Not sure if it's even possible seeing there is no video of someone performing that type of "surgery" on an rx gen3 dual.

    I have seen videos of people fixing older and bigger mods, that had more room to work inside, but because they were using their hands to keep both the tools and mod steady, did a "messy" job.

    DJslb reviewed the mod and suggested a TCR of 108 . Tried it and works better (had tried 88, 90, 92, 98 in the past). From my understanding, TCR is wire dependent as well. A slight change in the composition of the wire, is expected from manufacturer to manufacturer as there is no standard. And manufacturers don't list their TCR on the wire spool.

    Ti got much lower resistance than SS. Ti looks great for sub-ohming whereas I am mtl type with 1ohm and above wires.
     
    #12 k3rb3r05, Aug 22, 2019
    Last edited: Aug 22, 2019
  13. tim_buktu

    tim_buktu Member

    Joined:
    Jul 7, 2018
    Messages:
    39
    Likes Received:
    8
    :eek::eek:STOPP! Before start drilling and cutting through your case, watch this (don't care about the russian I don' understand nothing. too)
    just watch the video:
    In minute 5:22 you can see the most possible location of your problem: The press fitted threaded steal inlay of the 510.

    If you can solder a wire connection from the steal part of 510 to the PCB's Ground (GND: see minute 6:02 -> screwdriver) you will most likely fix that issue.
    You will need special flux to solder stainless steal

    If this will not work you can try to replace the 510 as second choice ->hammer it out drill a bigger hole and assemble something like this:
    https://www.aliexpress.com/item/328...chweb0_0,searchweb201602_7,searchweb201603_52
     
  14. k3rb3r05

    k3rb3r05 Member

    Joined:
    Aug 6, 2019
    Messages:
    32
    Likes Received:
    1
    Awesome find. Couldn't figure out how to remove the screen cover till I saw that video. Thx.

    At 6:02 are the battery leads though. Grounding is at 5:52, those 2 "ears" at both corners of the PCB

    Here is a fast-paced reassembly:
    starts at 11:48

    For time time being, I just ordered the joytech espion 200w. With redpanda loaded on it, it has smooth TC. A friend showed me his graph (https://nfeteam.org/forum/threads/the-best-box-supported-by-arcticfox.243/page-4#post-10941) and said it's up to par with his dna250c mod.

    If i do decide to mess around with the 510 on the RX, I'll just get a veritube v2, 11.5mm height, 13-14mm total needed for pin movement. It should fit nice in the RX. In the video link above, you can see the pin housing at 11:27. I will have to remove that part, but it looks about 10mm tall, so don't think i have room for a long 510 in there

    On second thought, I don't think I can install a 510 unless i find a work-around in positive and ground being soldered straight to the PCB. I will either have to use very long wires, which there isn't much room for or will have to use some sort of clamps (mini alligator clips ?) at the PCB end of those wires, which clips will be attaching to something sticking outwards from the PCB (for example a rod ?). Else I will be forced to desolder every time I open the mod for service and resolder again when closing.

    But then we open a can of worms. What happens if either/both of those 2 clips become loose, from an accidental drop on pavement, for example, and the fire button is pressed?

    Note: They way they have set it up, after removing the battery door, you can't really disassemble the mod unless you remove the PCB. And you can't remove the PCB if it is permanently attached to the 510 pin, by either just the ground or both ground and positive
     
    #14 k3rb3r05, Aug 24, 2019
    Last edited: Aug 24, 2019
  15. tim_buktu

    tim_buktu Member

    Joined:
    Jul 7, 2018
    Messages:
    39
    Likes Received:
    8
    the latches at time 5:52 should be grounding, yes. But one of the Batterie latches (as I expect the negative) should be GND too.
    You can easily measure it, it must have connection. The screwdriver is on the negative latch, see the labeling on the PCB.
     
  16. k3rb3r05

    k3rb3r05 Member

    Joined:
    Aug 6, 2019
    Messages:
    32
    Likes Received:
    1
    If I had a multimeter, I would. What precision should I look for? mOhm?
     
  17. tim_buktu

    tim_buktu Member

    Joined:
    Jul 7, 2018
    Messages:
    39
    Likes Received:
    8
    :DWhen you ask for precision, I need to ask: what is your budget? Will you use the multimeter later on for other projects ?
    I would recommend for your first multimeter not to buy the cheapest one, something like this will do:
    https://www.amazon.com/Neoteck-Mult...ds=multimeter&qid=1566735880&s=gateway&sr=8-6
    But you should not expect to much from the resitance range of (any) multimeter. Don't ask for mOhm :D
    Theese are special instruments for special use. If you want a second opinion to your coil resistance a Coilmaster Tab could be an usefull tool.

    But just for checking what connection point goes to where, a simple beeper can do the job. It could be even possible to follow the connection layer on the PCB with your eyes (magnification?). As I saw in the video: Isn't there a GND land right beneath the negative battery latch? I bet theese two pionts are on same potential.
    The most difficult point ist to solder the steel part of the 510 without messing all up.
    You will need a strong soldering iron (but not chunky) because the heatflow into the case will be heavy.
     
  18. k3rb3r05

    k3rb3r05 Member

    Joined:
    Aug 6, 2019
    Messages:
    32
    Likes Received:
    1
    I got one already

    You are right, there is. But, can't use it. (I'll explain below)

    That is the easy part.

    As I said in an earlier post, the way they have set it up now, in order for someone to service the box , they will have to slide out the PCB, which is attached to the battery compartment / cover. But the PCB won't be able to slide out if either the positive or GND is permanently attached to the 510.

    The GND by the negative (-) is too deep inside to be of any usage

    As you will see, there is barely any free room inside the case.

    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     
    #18 k3rb3r05, Aug 26, 2019
    Last edited: Aug 26, 2019
  19. tim_buktu

    tim_buktu Member

    Joined:
    Jul 7, 2018
    Messages:
    39
    Likes Received:
    8
    Forget about the"Ground Posts" these are part of the problem. I want you to solder a proper wire to the 510 and connect it to the upper Ground. Look at the picture (the yellow arrows). I did this similar to my primo mini and that helped.
    BUT: to solder the 510 is not that easy.
     

    Attached Files:

  20. tim_buktu

    tim_buktu Member

    Joined:
    Jul 7, 2018
    Messages:
    39
    Likes Received:
    8
    to get pace for working from the front side you could ether remove yellow rectangle in picture below or use a longer wire and place it between PCB and inner frame (yellow line) when pushing the PCB back into the case. then you can connect it to the lower grounding brackets.
     

    Attached Files: