This is super cool, been looking for a good pair of hot tweezers for a while, I'll have to get one!
Dave, have you checked the tip grounding of the iron? The first part is whether the tip is grounded to the USB shield (the heater resistor in the tip is pretty low resistance so it can be worthwhile to check the tip to USB shield voltage while the iron is running), and the second part is whether the USB-C charger is grounded (unlikely given the lack of AC GND pin). It's not an immediate deal breaker, but I've had situations where i've blown components because my scope GND lead was still connected to the PCB while, and the soldering iron tip was floating around 60VAC!
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Some lessons i've learnt re USB-C soldering iron grounding:
- Is your USB-C power supply grounded? Almost all of them are not (eg the one sequire sent doesn't have the third gnd pin on the AC side, so it's not grounded). The grounded USB-C supply i've been using is of these 245W ones (see link at bottom). The only way i found to tell before buying was the 3 pin power plug visible in some of the images. I power my laptop, phone, and soldering iron with it when i'm travelling for work haha
- Does the USB-C iron have the correct pin connectivity to ground the tip. The Sequire C210 iron i have has the correct tip connections, but the Sequire C245 style iron had the wrong tip-sleeve-ring connections to the cartirdge! This resulted in high current+20VDC (referenced to USB-C GND) being toggled onto the tip at several kHz! Not good for most components :'(. I cut the traces and bodged to connection and now my one is fine, but was a bit of a pain!
If you're not sure of tip grounding, the easy solution is just to make sure every possible GND is disconnected from you PCB before you touch it with the soldering iron. That means scope GND leads, any programmers or debuggers that might be connected to you laptop, any non-isolated power supply grounds etc etc. Maybe this is just good practice and i've been cutting corners, but its such a pain to disconnect all the carefully balanced test leads just to change one resistor!
Don't get me wrong though, i love USB-C powered equipment and it's here to stay in my [portable] lab
. Bring on the 250W USB-C spec, i want a USB-C hot air gun!
This is the style of grounded 245W USB-C charger i bought (the link of the exact one is now broken):
https://www.aliexpress.com/item/1005008001950627.html?spm=a2g0o.productlist.main.17.7936YxV6YxV6u5&algo_pvid=120b02f0-d1a4-4a1b-81c1-0178e234a365&algo_exp_id=120b02f0-d1a4-4a1b-81c1-0178e234a365-8&pdp_npi=4%40dis%21AUD%21228.78%21114.39%21%21%211068.57%21534.29%21%402101c72a17309539945913507ec39d%2112000043220960110%21sea%21AU%21185752513%21X&curPageLogUid=GTycXw4b55E8&utparam-url=scene%3Asearch%7Cquery_from%3A