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Hi, everybody.

Sorry for the off-topic post, but at least it's related to electronics.
I can't seem to find the connector used on laptop computers for the
+19.5 V input. Anybody have a manufacturer and part number for such a
beast?

I ask because I'm redesigning a homebrew 25-6000 MHz synthesizer box I
built. At present, it takes in +15 V from a rather uncommon wall-wart
power supply, uses +15 V to power the oven-controlled crystal
oscillator, and drops +15 V to +5.5 V with an LM317 linear regulator to
go to the synthesizer chip eval board. Well, the LM317 gets pretty hot,
and the construction of the box is hand-wired, ugly, and unreliable, so
I'm designing a board with a dual switching regulator to take +19.5 V
down to +15 V and +5.5 V. I want to power it from one of those
ubiquitous laptop bricks, and as a bonus, I get a higher voltage, +19.5
V, to bias the PIN diodes on the yet-to-be-designed RF board.

Thanks for your help.

Jim

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There is no single connector. It depends on the brand, series and model number that the supply was made for.


Michael A. Terrell

Hi Jim-
seems like every time you turn around they develop a new connector....so no set standard and varies from brand to brand and even among the same maker. I generally just cut the existing connector off leaving a 6 inch pigtail for possible use at a later time..then put what I want on the end of the cable. ( i do the same for the pigtail and make? standardized connections)
gud luk
搁别苍é别

Sorry for the off-topic post, but at least it's related to electronics.
I can't seem to find the connector used on laptop computers for the
+19.5 V input. Anybody have a manufacturer and part number for such a
beast?

It depends on the laptop. Often they are impart some degree of smartness to the charger - an
additional pin the is a one-line serial bus where the laptop tells the charger what the maximum charge
current is for the particular model of batteries installed. Dell use that for sure - I found these in
the UK just by google searching - in my case leaving the serial comms pin disconnected just reverts
the charger to maximum current supply.

Craig

Jim:

Others have commented on the issue of the connector type(s); I don't
have anything to add regarding the physical connector(s). But looking
at the power (voltage-dropping) issue:

1. For the 15V oven-controlled crystal oscillator, perhaps a series
string of silicon power diodes could be used to reduce the 19V down to
(about) 15V. Silicon power diodes will drop voltage by (very roughly)
0.7 volts per diode.

2. For the 5.5V load, perhaps a series string of silicon power diodes
could be used to reduce the 19V down to a lower voltage (maybe about 8V)
to feed the input of the LM317. This would greatly reduce the power
dissipation of the LM317, compared to an input voltage of 15V (or 19V).
If I remember correctly, the minimum dropout voltage of the LM317 is
about 2.25 volts (check datasheet?)

Resistor(s) might also be usable in combination with (or in place of)
the diode strings mentioned above, if the load current(s) are somewhat
constant.

Also, some computer (switching) power supplies have spikes on power
up/down that might be of concern; they also may require some minimum
load current to initially start, and might also generate some amount of
electrical noise (you mentioned that you are building a synthesizer-
shielding and/or filtering issue?). (This is my understanding, but I am
as far from an expert on power supplies as it's possible to be...)

Sounds like an interesting project in any case!

Mike Dinolfo N4MWP

If you're referring to the barrel connector that Dell uses, you might find one of the old laptop docking stations at a thrift store and, possibly, get the connector from that. Maybe even an old burned out laptop might be a source.

Good luck with it,
Barry - N4BUQ

Indeed the are all different, when I can, I have chosen to standardize on
the 5.5 x 2.1mm connector which seems the most common, some laptops even
use it.

Some parts number can be shown at digikey by going to "Barrel power
connector" and narrowing down to the one you need.




On Mon, Jul 16, 2018 at 2:28 AM Craig Sawyers <c.sawyers@...>
wrote:

Sorry for the off-topic post, but at least it's related to electronics.
I can't seem to find the connector used on laptop computers for the
+19.5 V input. Anybody have a manufacturer and part number for such a
beast?

It depends on the laptop. Often they are impart some degree of smartness
to the charger - an
additional pin the is a one-line serial bus where the laptop tells the
charger what the maximum charge
current is for the particular model of batteries installed. Dell use that
for sure - I found these in
the UK just by google searching - in my case leaving the serial comms pin
disconnected just reverts
the charger to maximum current supply.

Craig

They do seem to be approaching some modicum of standardization finally. My sister had 2 laptops different brands and the power supplies were interchangeable, and my Gateway supply runs them as well. They are all about 19 volts and it seems the polarity has been matching. I noticed an older Gateway adapter would not work on my newer Gateway and I suspect it is because it pulls more current. Maybe not running but it might charge faster. The diameter of the whole thing is the same but the pin in the middle is larger.

Right now I have the whole Toshiba motherboard for sale but you don't want it for just that. It works so I don't want to turn it into a parts mule. the older laptop is going to be my music server on the garage if I can ever get the wireless to work on it. you might look around for a laptop that has been dropped or something, you are not going to do mass production, right ?

Another idea might be a music store that sells electric, they likely also have effects pedals and many of them run of a wall wart. I worked at a music store like that for a bit and they had 2 boxes full of wall warts, one box of AC and one box of DC. they migth have some pedals that they can't fix. You can just try the plug, not even powering it up. The voltage doesn't matter, as long as it makes the connection.

Also for a one off (that's what engineers call them I think) you can just cut the wire and put on any connector you please.

Oh, and your post would not be considered off topic in TestgearNotTekscopes. A computer is definitely test gear. Actually so are amplifiers if you work on tuners, CD DVD players, tape decks. A tuner can be a source for a test signal if you are working on an amp. The only thing that is not acceptable there is Tek scopes because I do not want to divert any traffic from this group. It is just too nice.

And any home brew test gear is VERY welcome.

Just so you know.

On Mon, 16 Jul 2018 13:12:56 -0700, you 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.

Secondly, there's a current limit that's also imposed. I have an HP
that wants higher current for the supply, and does not have the (older
standard) 5.5/2.1 (whichever *is* the "standard")) connector. It's
actually smaller in the barrel.

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.

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.

Bottom line, there *is* somewhat of a standard (don't know what it is)
that is now applied to barrel and pin diameters for different voltage
limits.

Harvey

They do seem to be approaching some modicum of standardization finally. My sister had 2 laptops different brands and the power supplies were interchangeable, and my Gateway supply runs them as well. They are all about 19 volts and it seems the polarity has been matching. I noticed an older Gateway adapter would not work on my newer Gateway and I suspect it is because it pulls more current. Maybe not running but it might charge faster. The diameter of the whole thing is the same but the pin in the middle is larger.

Right now I have the whole Toshiba motherboard for sale but you don't want it for just that. It works so I don't want to turn it into a parts mule. the older laptop is going to be my music server on the garage if I can ever get the wireless to work on it. you might look around for a laptop that has been dropped or something, you are not going to do mass production, right ?

Another idea might be a music store that sells electric, they likely also have effects pedals and many of them run of a wall wart. I worked at a music store like that for a bit and they had 2 boxes full of wall warts, one box of AC and one box of DC. they migth have some pedals that they can't fix. You can just try the plug, not even powering it up. The voltage doesn't matter, as long as it makes the connection.

Also for a one off (that's what engineers call them I think) you can just cut the wire and put on any connector you please.

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.

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.

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 <JURB6006@...>
To: [email protected]
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.