Re: OT: +19.5 V connector on laptop computers


Leon Robinson
 

I just got a 19.5 volt 45 watt HP supply today.
The connector is a large 3 contact coaxial, Positive Center pin, Negative Outside Sleve
and Voltage control on the Inside Sleeve.
Voltage measured 13.4 from Outside to Center Pin with the Inside Sleeve open.

Voltage measured 22.2 from Outside to Center Pin with the Inside Sleeve shorted to the Center Pin.
I will probably cut the connector off for my use, because the Supply will be mounted
inside the case along with the other circuitry. Leon Robinson    K5JLR

Political Correctness is a Political Disease.

From: Jeff Urban <@JURB>
To: TekScopes@groups.io
Sent: Thursday, July 19, 2018 9:12 PM
Subject: Re: [TekScopes] OT: +19.5 V connector on laptop computers

On Mon, Jul 16, 2018 at 05:08 PM, Harvey White wrote:


I've seen a standardization to several end destinations. One is that
the voltage rating seems to determine the size of the barrel
connector. That's now, from what I can see.
You mean the outer diameter ? It seems the pin is more based on the current. this laptop, I can plug its adapter into a smaller and older laptop, but the for it will not plug into this one because of the pin diameter.

I'm going to conclude that there's an evolving standard out there, and
I have no idea of what it is.

Now, that is completely screwed up by the "DELL" standard, which
apparently includes some HP laptops.

Dell has a 3 wire cable to the power supply brick. The inner pin is
apparently an I2C connector. The inner and outer shells are power and
ground (suggest that the outer is ground). In a DELL computer, if the
power block does not identify itself as a "genuine" power adaptor,
then the battery will not charge.
Typical corporate behavior.  Captive market is king. If they continue this and sell enough of them like that then a market will be created for aftermarket chargers. It is not all that difficult. Just a matter of a custom tailored current output and their batteries are not of any brand new technology that doesn't exist yet.

Those adaptors (and don't ask me what I think of them) work with a
different standard. Not sure what the effective voltage and current
limits are in this case.
That's why we have test equipment. Take all OEM parts and let them work together a couple of times, Measure everything. Would I do a one off for myself ? No, I would get rid of the thing. I almost didn't buy these Gateways but the price was right. Large screen, full keyboard and 2 HD bays. But though there are multiple connection on the batteries (I have 3 I think) but the adapter only has 2, so there is none of that captive market shit.

I  used to build all my own PCs, and some for others, but you really can't do that with a laptop.

Actually for Jim's needs, there are probably surplus VCR power supplies that would do the job. For a one off it might be free on Craigslist or whatever. They fry out but with a new chopper, sometimes another transistor and changing the caps they can definitely do the job. Inmost the 3 major caps they need are those in the pi filter for the 5 volts because it feeds the feedback loop, and there is one in the snubber without which the chopper will short. Very rarely any other parts except do change a bunch more caps.

It's a thought.

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