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I would like to replace the USB-C male plug in my lenovo charger to new one. Cable has 3 wires and the plug that I bought have 4 pins. Is it possible to connect these two toegheter or I need other plug ?

photo 1

Toto
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jjakubos
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  • Can you not reference the original charger piece that broke? – gregg Feb 23 '23 at 13:46
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    I don't think a USB C charger 'should' be 3 wires, and a USB C connector has a lot more. It'll make a lot more sense to buy a USB PD charger with a detachable cable than try to solder what looks like heavy gauge connectors into what looks like a fine pitch breakout board. – Journeyman Geek Feb 23 '23 at 15:01
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    I mean, it could have 3 wires of the plug end of the cable has added intelligence to talk to the “main body”. A regular plug definitely wouldn’t do then. – Daniel B Feb 23 '23 at 20:57
  • indeed, I would bet the original plug had some electronics in it – user253751 Feb 24 '23 at 18:54

3 Answers3

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I think the general consensus with the issue – like this Reddit thread – is that it's not something you can repair.

Firstly a 'decent' USB PD power supply isn't 'very' expensive, can last you through multiple laptops in theory, and if it's a detachable cable you can 'just' replace the cable in future.

You'd also need to somehow figure out how the pin out relates to those wires, and you're attempting to solder what looks like heavy gauge wire to fine pitch connectors, possibly on both sides of the connector. You'd need to know which. It's also possible that there might be some logic on the charger side.

C1 R3, R2 and R1 are not pins by the way – they are pads for a capacitor and 3 resistors, and one resistor is populated. Soldering to them would be a terrible idea. From this, well, honestly, you really shouldn't be doing this, and lack the knowledge needed to do this safely. (I don't either! I just know enough to know this is a mistake!)

Basically If you mess up badly enough, you could damage your laptop and set your house on fire. It's well worth just junking this and getting a new one, even if it feels like e-waste.

Laurel
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Journeyman Geek
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    +1 Yup, this looks about as wise as hammering a 6" nail through your screen to hang it on the wall. – Tetsujin Feb 23 '23 at 16:34
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You can't do this with (only) the hardware in the picture.

The cable would appear to have a single voltage, and the plug is missing the hardware required to negotiate and modify the voltage required by the USB PD spec and needed to go above 5 volts/2 amps - which is almost certainly demanded by the laptop.

Update -

It seems the plug you have has 4 pads on the bottom - not shown in yor picture but visible in some pics at https://www.aliexpress.com/item/1005004709783126.html

Have a look at https://electronics.stackexchange.com/questions/475079/usb-c-connector-wiring-3-wires - this thread was never resolved but it strongly implies that the connector Lenovo are using are non-standard (3 wires - most USB connectors have 4). The replacement USB board you have purchased is not the correct one for your application.

On the + side, that electronics.stackexchange site says if you get https://www.aliexpress.com/item/1005001940524279.html you can join that to your existing power supply to make a working cable.

davidgo
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    I wouldn't put it beyond companies to build a non compliant, single voltage/purpose charger to save a few bucks.... or to put that hardware *in* the wallwart/power brick - and that plug 'does' have space for a resistor or 3 which might be enough? IF correct. There are o many variables that could lead to unexpected release of magic smoke. – Journeyman Geek Feb 24 '23 at 01:58
  • @JourneymanGeek Your comment prompted me to go looking further. I've done some digging and updated my answer. – davidgo Feb 24 '23 at 03:22
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    Your linked EE Stack Exchange article explains you only need 3 wires for a USB-C PD charge-only connector: Power, Ground, and CC1. You would need 4 wires for a USB-C supporting only USB 2.0 data. It's the wrong type, but it's in the most logical configuration. It's not non-standard, since there's no standard for internal wiring like that either, for example, there may be wires for a power LED. – user71659 Feb 24 '23 at 05:09
  • Your aliexpress link is probably a better idea, though then there's the matter of either safely splicing the wires (there's these self soldering heat shrinks that would be perfect) or opening the PSU case without too much damage. Still, a 'proper' replacement is a good idea – Journeyman Geek Feb 24 '23 at 11:57
  • @JourneymanGeek: It doesn't matter how much space his replacement plug has, but what was in the original one he chopped off. Which could easily have had a PD-negotiation IC. – Ben Voigt Feb 24 '23 at 15:13
  • Oh - more of what is visible from the photo is pads for components, not pads for soldering. And soldering heavyish guage cable into small pads is not fun – Journeyman Geek Feb 24 '23 at 15:17
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    @JourneymanGeek if a major, well known hardware brand like lenovo shipped chargers that were sufficiently noncompliant as to unexpectedly output anything above 5V on USB-C, that would have raised MAJOR attention due to a lot of people ending up with damaged devices (using your USB-C laptop charger also for phones or accessories is quite common practice nowadays).... – rackandboneman Feb 24 '23 at 22:26
  • This USB cable is a standard USB C charge only cable. For charging only, you only need GND, VBUS and CC. – Ferrybig Feb 25 '23 at 16:11
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USB C PD chargers with captive cables require a minimum of three wires. VBUS, CC1 (or CC2) and GND. I strongly suspect that the bare wire/shield is "ground" (in the sense of logic ground, which may or may not be connected to mains ground), the thick red wire is Vbus and the thinner blue wire is CC1.

To test this, connect a 5.1kΩ resistor between the blue wire and the shield. Then plug in the power supply and measure the voltage on the red wire relative to the shield. You should get +5V. You may or may not get 5V even without the resistor. Higher voltages should not be supplied until/unless a USB PD supporting power supply requests them.

Connecting to your laptop is a different problem, soldering those wires to a tiny PCB is going to be a PITA, even if you find the right PCB, and I don't think you have the right one.

Splicing the cable may well be an easier approach. Someone over at https://www.aliexpress.com/item/1005001940524279.html would be the correct cable to splice to, but personally I would want to verify it's wiring with a multimeter and a breakout board before trusting it.

plugwash
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