Re: OT: +19.5 V connector on laptop computers


Harvey White
 

On Thu, 19 Jul 2018 19:11:56 -0700, you wrote:

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.
The outer diameter. I've seen 6, 9 and 12 volt adaptors where the
plugs will not go into something with the "wrong" voltage requirement.
The older ones seem to standardize on one thing and it's up to you to
hit the right voltage.

I design all my stuff with polarity protection, and the voltage
limiting/protection is starting to be a design feature, too.


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.
Now ask what happens if the MOTHERBOARD won't recognize a valid power
adaptor.

Now ask if I buy any more DELL computers.


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.
Not a connection on the battery. Didn't look and didn't at that time
care. Power brick and laptop.

Harvey



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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