KSGER T12 bootloop with J02 tip - Page 1
Forum section: electronics / general

author: Richtermann
author_rank: Newbie
timestamp: May 05, 2022, 10:30:59 pm
content: Hello!I have seen eevblog as being active regarding this popular soldering station.I bought one, when it was hyped on YouTube over and over and instantly modded if, like the cooling metal to not touch the trace below and the other little things that should be fixed.HW versions is: 3.10SW version is: 3.2SThen I have been using it for half a year with my J02 tip.One day it suddenly crashed and from then on bootlooped all the time with the J02 tip inserted.By bootloop I mean, that only the "KSGER" text appears on screen with one single short beep, and then it goes black. Then the logo appears again and there's the next beep. This repeats with a frequqency of about 1Hz, over and over.From then on this problem would remain.If I start the station with the J02 tip inserted it will crash and bootlooop. If I insert the tip while the station is running, it will also crash and bootloop.All the other 20 tips I have are still working.So I threw the J02 tip into the garbage and bought a new one - and the problem remained!J02 crashes and bootloops the station, and all the other tips are working (including the very similar JL02 for example).What could be the reason? Is my station broken? I have already reset the firmware.I have measured the reistance on the tips' contacts and have found the J02 to actually havbe the lowest resistance of all (7.9Ohm), while all the others are 8Ohm+There's another strange think I noticed about the station:After calibrating a tip it's name ist displayed as inverted in the OLED display to show it's calibrated. But when switiching to another tip and back, this indication is gone - the name is displayed normally again. Is this behaviour normal?Thank you!

author: DavidAlfa
author_rank: Super Contributor
timestamp: May 05, 2022, 10:55:37 pm
content: Probably shorting out, not at low voltage, but arcing internally when 24V is applied.Happened to me once, the isolation inside the T12 tip melted and the wires touched.Before turning off, it had enough power to burn both the mosfet and T12 socket.Throw that tip away before it blows everything!

author: floobydust
author_rank: Super Contributor
timestamp: May 05, 2022, 11:50:28 pm
content: Don't run the soldering station like this, it can stress the power mosfet too much. A shorted heater/wand wiring/shorted connector can do this.Your 24V power supply might be failing under load, when the heater is switched on. I would check it.The firmware is not that great.

author: Richtermann
author_rank: Newbie
timestamp: May 06, 2022, 01:00:20 pm
content: Hello!The issue is that I already ditched the old J02 tip because of this problem and bought a new one and still have this problem.I cannot use the station like this at all, because it won't power on, but loop-crash.Other tips are working.So should I just buy a 3rd J02 tip and hope it will work this time?

author: DavidAlfa
author_rank: Super Contributor
timestamp: May 06, 2022, 01:27:28 pm
content: Check the impedance measuring at the connector pins, with the tip inserted in the handle.

author: ygi
author_rank: Regular Contributor
timestamp: May 06, 2022, 01:46:15 pm
content: Well you never know with cheap Chinese stuff but still, it would be some serious bad luck to get the same fault with 2 different tips.Could it be that somehow J02 tip profile's corrupted and crashes the firmware when it tries to load it?

author: Richtermann
author_rank: Newbie
timestamp: May 11, 2022, 05:14:31 pm
content: HelloI now found time to measure resistance in between the iron's plug contacts:These are the values from the non working tip (J02)(nc = not connected)1 to 2 changing all the range from 8kΩ to not connected, motion dependent1 to 3 changing all the range from 5Ω to not connected, motion dependent1 to 4 changing all the range from 1Ω to not connected, motion dependent1 to 5 changing all the range from 5Ω to not connected, motion dependent2 to 3 8.6kΩ2 to 4 8.6kΩ2 to 5 8.6kΩ3 to 4 7.6Ω3 to 5 changing all the range from 4Ω to 30Ω, motion dependent4 to 5 changing all the range from 5Ω to 4Ω, motion dependentAnd these are the values from the similar, but working tip (JL02)(nc = not connected)1 to 2 nc1 to 3 changing all the range from 20Ω to not connected, motion dependent1 to 4 nc1 to 5 nc2 to 3 nc2 to 4 9.3kΩ2 to 5 9.2kΩ3 to 4 nc3 to 5 nc4 to 5 9ΩWell.. obviously there's something very fishy going on..I also noticed the problematic tip (J02) giving a rattling noise when shaking, which I didn't notice before, because the iron itself is ratling too with it's internal motion switch.So did Ireallyget a new tip with the very same defect as my old tip had?Seems just so unlikely, but could anything else be the issue?

author: Richtermann
author_rank: Newbie
timestamp: May 11, 2022, 05:17:18 pm
content: Quote from: ygi on May 06, 2022, 01:46:15 pmFor a moment I though same, but then:This station does not automatically assign internal profiles to physical tips. You have to select the matching profile for a tip manually, and the problem occurs no matter what tip is selected in the menu.

author: ygi
author_rank: Regular Contributor
timestamp: May 11, 2022, 07:42:01 pm
content: There's no more room for doubt, the heating coil's broken (that's the rattling noise) and is now electrically in contact with the grounded metal housing. A good tip would have something like 4~6 megaOhm between the metal cartridge body and both + and - terminals of the heating coil. That's a one-way trip to the trash for that J02.

author: Richtermann
author_rank: Newbie
timestamp: May 16, 2022, 08:52:39 pm
content: OK then.. guess I got to buy another one!Thank you all!