Shinenow T12 station reversed power cable - Page 1
Forum section: electronics / general

author: p_wats
author_rank: Contributor
timestamp: July 30, 2020, 02:20:24 pm
content: After reading just about every topic on T12 soldering stations this forum had to offer, I figured I was ready to tackle the potential safety concerns of my own. I should preface this by also offering that I've built a few tube amps and am not uncomfortable around mains wiring (I initially posted this on Reddit, as I already had an account there, but this seems to be the go-to place for all things T12 safety).I bought a Shinenow T12 soldering station from Amazon, as this particular one was not much more expensive than getting one from Aliexpress, etc. and had good reviews on both the Canadian and American product listings (as well as faster shipping--my last Aliexpress orders took months to arrive).https://www.amazon.ca/Soldering-station-portable-Temperature-Controller/dp/B075PDNTMK/ref=cm_cr_arp_d_product_top?ie=UTF8I received it yesterday, knowing I'd have to ground the case, as the listing even provided instructions. However, after opening mine up I see that it's not the same power supply board as the photos in the listing. That's not the end of the world, as I've seen different models with different power circuits (I've since been in touch with the seller, who says the PSU has been "improved" since the photos for better heat dissipation---those giant heat sinks, I suppose).However, when I checked the mains wiring (using my multimeter to test continuity via the supplied IEC cable) I noticed that something looked off: live seemed to not be fused, with neutral going to the fuse instead.Coincidentally, I had received a cheap hot air station in the order as well and was warned to check the IEC cable, so I checked both and they are each reversed from standard North American wiring (ie, live and neutral are swapped).Not a big deal, as I can source another IEC cable to use. Though with a proper cable the T12 station now has live going through the fuse, then onto the PCB at a point labelled "N" (I assume for "Neutral"), and Neutral goes to a point labelled "L" (for "Live").I assume, to be safe, I have the following options:Use the proper IEC cable, so the live wire at least goes through the fuse (and ground the chassis)Entirely redo the mains wiring myself, so I'm sure they are wired correctly (I'll have to do this with any other T12 I get anyway, as they all seem to have similar issues).Return it (the reason I went via Amazon was for the return policy anyway---and quicker shipping than elsewhere) and buy one of the KSGER/Quicko units from Aliexpress, again knowing I'll have to check the mains wiring/ground, etc.

author: p_wats
author_rank: Contributor
timestamp: August 01, 2020, 02:25:41 pm
content: For what it's worth, the seller and I have been talking. They refunded me the cost of a new IEC cable and have provided the attached schematic for the power supply, so that I can do the grounding, as per North American standards.I noticed in the actual unit the power supply board itself is never grounded--the mains ground wire goes straight to the soldering iron controller board.I assume it's in my best interest to both ground the chassis AND ground the FG point on the board.

author: Nusa
author_rank: Super Contributor
timestamp: August 01, 2020, 03:33:51 pm
content: I find it amusing the date on that schematic is yesterday. It may not be an exact match to the actual hardware you have, but likely close enough for your purposes. And of course they didn't give you the schematic for the rest of it.If you're asking if you should connect chassis ground and power supply grounds (there are two, you'll notice, isolated by T4 and U2, but connected by CY3), the answer is no.The earth ground may or may not be connected to the tip, either directly or via a 1M resistor. I don't know what that iron is supposed to have, and I would be cautious about changing it. You might find this discussion interesting:https://www.eevblog.com/forum/chat/does-you-soldering-iron-have-grounded-tip/msg46583/

author: p_wats
author_rank: Contributor
timestamp: August 01, 2020, 05:39:36 pm
content: Quote from: Nusa on August 01, 2020, 03:33:51 pmHa. I never noticed the date on that schematic. Convenient.Thanks for the info. I'll read through that thread as well.Currently there is no chassis ground, so that was to be my first step (after getting rid of the reversed IEC cable) and it sounds like connecting FG to chassis ground may not be necessary?This unit is advertised as ESD safe, but I assume that may not actually be true, so won't bank on it.