Vintage laptop power supply trouble

[Myronazz]

Hello...!

Sooooo I found this really cool vintage laptop from 1990 but unfortunately, the seller is missing the power adapter AND the connector is actually quite strange and not common at all, i found an adapter but it costs £60 which is way too much for a power adapter, so i thought i'll do this my way and solder a different connector, i do have some minimal soldering experience and a soldering iron so why the heck not, the problem is that the connector has 4 pins, i found what each pin is from pictures from the power supply, they go like this:

I have no idea what "RC" and "COM" are and if they are necessary but not only that, i can't make out which pin is negative and positive from this, so maybe you guys can explain what all that is and what my options are, can i just connect power and skip the other two pins?

Since it has four pins, i thought i'd get a female USB port to replace that weird port, kind of stupid but if i can figure out the wiring, it should work, right?

Thanks, hopefully you guys can help me figure this out

 

[jay32267]

Would you please type what it says next to pin one and pin 2?

 

[Myronazz]

Would you please type what it says next to pin one and pin 2?

Here is what each pin is, according to the picture
PIN1: DC21V 1.9A
PIN2: DC21V 1.9A (CC)
PIN3: COM
PIN4: RC

That's all there is to it, i'm really sorry for the late reply, i thought nobody replied to the thread because for some reason i didn't get an email notifying me that i got a response, i usually get one but apparently, not this time

 

[jay32267]

That's Ok.
Here's what I think. You need a 21VDC supply. The red goes to both pins one and two. the black goes to common.

As far as how many amps for the supply....I'm reading that as you probably need only 1.9A but....it MAY mean you need 3.8A.

....as far as the RC terminal.....i haven't been able to figure that one out. I'm thinking maybe RC=remote control? Some sort of remote way to power it up? Not sure.

 

[Myronazz]

That's Ok.
Here's what I think. You need a 21VDC supply. The red goes to both pins one and two. the black goes to common.

As far as how many amps for the supply....I'm reading that as you probably need only 1.9A but....it MAY mean you need 3.8A.

....as far as the RC terminal.....i haven't been able to figure that one out. I'm thinking maybe RC=remote control? Some sort of remote way to power it up? Not sure.

So I should connect the positive wire to PIN 1 and 2 and negative to COM? I never expected that, splitting a wire to two pins? that's kind of odd
As for as amps go, i read somewhere that unlike voltage amps aren't fixed, which means that the device will only draw as much amps as it needs, it's just a matter of how much the power supply lets it draw

Thanks for the help, i really appreciate it, hopefully i can get that thing to work, thanks again!

 

[jay32267]

So I should connect the positive wire to PIN 1 and 2 and negative to COM?
Yes.

splitting a wire to two pins? that's kind of odd
Yeah it's a little odd....but that's what you do in this case. The (cc) means it's a duplicate.

You could probably get away with using just one....but it's safer to use both.

as far as current....the PSU will only supply as much as the PC draws....

but it's hard to tell what they mean being how they have it labeled.

If you get a 21VDC PSU....and it's rated 3.8A or above....you definitely will be fine.

The 21 VDC HAS to be 21 VDC though. You can't have any other value for that.

 

[Myronazz]

So I should connect the positive wire to PIN 1 and 2 and negative to COM?
Yes.

splitting a wire to two pins? that's kind of odd
Yeah it's a little odd....but that's what you do in this case. The (cc) means it's a duplicate.

You could probably get away with using just one....but it's safer to use both.

as far as current....the PSU will only supply as much as the PC draws....

but it's hard to tell what they mean being how they have it labeled.

If you get a 21VDC PSU....and it's rated 3.8A or above....you definitely will be fine.

The 21 VDC HAS to be 21 VDC though. You can't have any other value for that.

Unfortunately, i don't have a power supply with exact 21VDC output, but i've gotten away every single time with using a power supply with slightly less or more voltage, the one i have right now is 19VDC 3,89 Amps
I know i'm not supposed to.. but the worst thing that can happen is the laptop not powering on due to under voltage, right?