Wiring/connector issues



  • Greetings,

    To clear a bad filament jam last week, I had to remove my T3P3 effector/hot-end from the printer. This necessitated disconnecting the 12-conductor wiring harness connector and removing the PTFE tube from the E3D-V6. I recall the connector being difficult to separate. Once the jam was cleared, I put everything back together, and all seemed fine, but I started to notice hot-end heater faults. These were very intermittent. They seemed worst when homing the Kossel Mini. I tried to find the fault by wiggling the wires, both in the bundle a few inches from where it attaches to the connector, as well as wiggling individual wires at the connector. I could get no consistent fault. When testing this way, I also noticed the hot-end fan would slow and speed up as if those wires were now intermittent too.

    If this were a simple dupont connector, I could press down on an exposed area of the pin through the plastic, to remove the wire from the connector, but I don't see a way to do that here. Is there a way to pull the individual wires/connectors out of the plastic shell?

    I'd love some advice. At this stage I fear I'd have to cut off the whole connector and a few inches of wires, and splice in all new wires. I'd rather avoid that - especially as I am not sure the fault isn't on the other side of the connector that is attached to the quick disconnect PCB.

    Thanks,

    John


  • administrators

    The pins on those connectors lock in and there is not the easy release like on a molex kk or Dupont. If you have a ohmmeter/continuity tester you can measure the continuity of each wire while moving the harness about to confirm if it is the pin in the connector (more likely) or the PCB (less likely). If it is the connector the best option is to cut it off and re fit a new set of pins and connector (contact us for the parts info@duet3d.com)



  • Thanks Tony,

    I'll check the continuity this evening.

    John



  • I spoke with Tony about this at MRRF, and I've done more testing, but I can't get a consistent fault when testing continuity with my multi-meter. Is it possible the Duet is more sensitive that my USD$25 multi-meter and not sensing the intermittent faults?

    Here are the steps I've taken.

    • Unplugged thermistor wires at DuetWifi, and individually checked both wires back to the 12-pin connector. Wiggling the main wire bundle near the 12-pin connector showed no break in continuity tone, and the resistance showed .3 to .5 throughout the testing.

    • Did the same for the two heater wires between DuetWifi and 12-pin connector. Same results as above.

    • Unplugged the E3D-V6 heater from the green PCB board connector and tested between there and the 2 corresponding male pins on the PCB-board side of the 12-pin connector. Same results as above.

    • Unplugged thermistor wires from the PCB connectors and tested between those two wires and the 2 corresponding male pins on the PCB-board side of the 12-pin connector. Same results as above.

    • I also tested resistance to the thermistor, and it registered a steady 115k ohms - wiggling wires made no difference.

    • I also tested resistance to the heater, and it registered a steady resistance of 4.1 ohms. Again, wiggling wires made no difference.

    So - I'm stumped. The problem started after I had to unplug the 12-pin connector, which took some force, which is why that has been the focus of my investigation, but I can't seem to get any manual tests to fail, but when I hook everything back up and home the printer or start a print, I'll get enough blips that it looks like a heart EKG, and sometimes it'll register an open.

    Thanks for any additional advice.

    John



  • To close this out, I decided to create a new two-wire connection that bypassed the 12-pin connector. I started by replacing the thermistor connection. It works fine. So - I didn't find the true source of the problem, but I did isolate it to the thermistor pair of wires and not the heater wires.

    This workaround is acceptable to me, and less hassle than replacing the 12-pin connector and likely having to patch in additional wire length. 🙂


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