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USB-C/PD to Lenovo small-barrel (5.5x2.5mm) adapter - good or bad idea?

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USB-C/PD to Lenovo small-barrel (5.5x2.5mm) adapter - good or bad idea?

#1 Post by ragefury32 » Sun Nov 29, 2020 11:34 am

Quick question -

Is buying/using a USB-PD to IBM small-barrel (5.5mm outer/2.5mm inner, yellow ring tip center polarity) like this one a "good idea"?


The barrel seems to fit the specs but I am a bit weary about pumping 18-20v into a machine that normally accepts 16v. I am thinking about buying/using one with a Thinkpad 240 and an X31. Hopefully there is a way to step the voltage down from 20 to 15 or 16v - maybe by reprogramming the USB-PD protocol negotiations to always to 15v instead?

Anyone have any experiences with an adapter like this?
X31 (2672-C2U)
X41 Tablet (1869-CSU)
Thinkpad X1 Carbon Gen 6 (20KH)

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Re: USB-C/PD to Lenovo small-barrel (5.5x2.5mm) adapter - good or bad idea?

#2 Post by rkawakami » Sun Nov 29, 2020 1:26 pm

Short answer: Spend about $15 to get a proper 16VDC Thinkpad adapter. Your equipment will thank me for that.
Ray Kawakami
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