Problem with original T245 handpiece with Aixun T420D welder - Page 1
Forum section: electronics / general

author: flaspad
author_rank: Newbie
timestamp: June 20, 2023, 02:21:22 pm
content: Hi all, I have a problem with the handpiece that came to me with the Aixun T420D welder. Basically as soon as I connect the T245 handpiece and turn on the welder it gives me a short circuit error, while if I connect the T210 and T115 handpieces they work perfectly. My doubt is that they soldered the pins of the T245 connector wires wrong at the factory. Does anyone have the connection diagram of the pins of the original connector and its connection to the C245 tip? Thank you very much. I tried the search button but only found the changes.I attach video of the short circuit fault.https://youtube.com/shorts/gAx8ILK6qUohttps://youtube.com/shorts/76mWViP__1U

author: thm_w
author_rank: Super Contributor
timestamp: June 20, 2023, 09:31:47 pm
content: If you plug in the handpiece with no tip, does it also give a short circuit error?The pinout should be normal JBC pinout. You can google for that, eghttps://github.com/Jana-Marie/Otter-Iron-PRO/issues/16

author: flaspad
author_rank: Newbie
timestamp: June 21, 2023, 09:56:21 am
content: Thank you very much , I solved the problem

author: breeze1113
author_rank: Newbie
timestamp: January 03, 2024, 10:44:25 am
content: Hi, i have the same problem, how did you resolved it? Thanks

author: GnomeZA
author_rank: Regular Contributor
timestamp: January 03, 2024, 11:17:04 am
content: Quote from: breeze1113 on January 03, 2024, 10:44:25 amTry removing the connector of the hand-piece?I posted a picture here of mine:https://www.eevblog.com/forum/reviews/any-opinions-on-the-aixun-t420d/msg5251509/#msg5251509I also did a tear-down of the stand if you want to check for short circuit there.And finally double check the stand output connector also has no short-circuit.It is definitely unfortunate you got a not functioning stationI should add that opening the connector is very easy. You unscrew the screw and then use a flat screw driver and press down on this part:Then you can slide off the connector.It'll be fairly intuitive once you are doing it what I mean.Initially I tried pressing down on the thumb part, but it is actually easier with the flat screw driver on that flat part where I show

author: breeze1113
author_rank: Newbie
timestamp: January 03, 2024, 04:34:32 pm
content: Thanks for the help. There some diferances of my stands. I have opened them and there are 2 different boards inside. The right one which is giving me short message is stamped as jbc-r. Its interesting, maybe it is for jbc original handles.

author: GnomeZA
author_rank: Regular Contributor
timestamp: January 03, 2024, 05:04:08 pm
content: Quote from: breeze1113 on January 03, 2024, 04:34:32 pmNo I don't think so, I'm using JBC original T245 hand piece and I have the second one (if you saw my post in other thread).Have you checked for shorts with multi-meter?Connector on the board marked JBC looks good to me.But the T420D looks a bit marginal, like those solder blobs are very close to each other.Still I don't see anything obviously wrong there.If you have some 99% isopropyl alcohol and an old tooth brush you can maybe try clean up those boards to get the flux off.

author: breeze1113
author_rank: Newbie
timestamp: January 03, 2024, 05:29:57 pm
content: Quote from: GnomeZA on January 03, 2024, 05:04:08 pmI cleaned the boards, the board marked t420d is working just fine. The other board is showing short on the soldering station and the connection to the pins are differant. The c210 handle is working fine, but the 245 not. If i am connection the left base to the right side the 245 handle is also working fine. So it is obwiisly the right base with the board marked jbs the problem.

author: GnomeZA
author_rank: Regular Contributor
timestamp: January 03, 2024, 05:55:31 pm
content: Quote from: breeze1113 on January 03, 2024, 05:29:57 pmOh interesting. If you have the time, any chance you could take photo of your T210 hand piece pin out and trace the pin out on that other stand and put it in that T420D thread? I think it would be super helpful for someone like me who bought the T420 (not D) if I want to go for T210 in the future.So it sounds like it is "working as expected" except that you can't just put any hand piece on any stand

author: breeze1113
author_rank: Newbie
timestamp: January 03, 2024, 08:25:11 pm
content: So here are some pictures and cable color pinout to the soldering station and the pinout from the base to hand piece. Note: the black and the blue are shorted by the pcb. I don't know why t is so different the pcbs of the right and the left base. Maybe it is made to not connect for example 2 245 hand pieces( just an Idea). Maybe it could be helful for someone. At this moment I can only connect the t245 hand piece to the left side base and the 210 to the right one.

author: litris
author_rank: Contributor
timestamp: March 14, 2024, 08:36:17 am
content: Quote from: GnomeZA on January 03, 2024, 05:55:31 pmCan you confirm me that the T420 no "D" is 200w.In the manual it says 100w but in the web specs it says 200.All of their lower models are 200w.The AliExpress seller send me a screenshot of the specs and it says 120w 🤷🏻‍♂️Every site I look at has a different value, I don't want to buy a station lower in power than a 200w T3A.The T420D does show 200w in the manual.Thank you.

author: thm_w
author_rank: Super Contributor
timestamp: March 14, 2024, 08:45:50 pm
content: T245 handpiece won't use more than 120 or 130W so it doesn't really matter.edit: the spec on their site is 200W so I would trust that, not some random ali sellers specs.

author: litris
author_rank: Contributor
timestamp: March 15, 2024, 08:48:42 am
content: Quote from: thm_w on March 14, 2024, 08:45:50 pmPerfect! Thank you very much.Right now I answer me saying the same thing that it is 200W that I was right.

author: Meter Deter
author_rank: Contributor
timestamp: November 09, 2024, 09:41:43 pm
content: Breezedid you fix the smart Holder short??i just got T420D and the left smart Holder has a short too.holder will not recognize iron when set down . to go on standby

author: breeze1113
author_rank: Newbie
timestamp: October 02, 2025, 01:43:22 pm
content: Sorry, haven't noticed your message as there were no notification, I know my answer could be too late. I claimed the seller and presented pictures and he sent me a new stand, with the new one both are working correctly. It is possible to tear down the stand and do fix the connections on the board which is inside the stand. You just have to tear down both stands and compare the boards. Regards