Heated bed - change of voltage from 12v to 24v.

[Macflame]

I am rewiring my heated bed to take 24v. I cannot seem to clean up position 1s solder pads. From diagrams I can see that the solder point 1 had two solder pads. Mine seem to be fused together.
I have tried loads of liquid flux with solder wick, adding more solder and I just can't seem to part the pads. The residue melts but stays fixed.
Is it necessary that both pads are separated?

[William]

Hi, from your picture, you need to separate it.

[_kaktus_]

Hello.


I'd like to see a picture of all the soldering pads on your heated bed.

[Macflame]

here is a photo of what the board looks like now. It is for 24v usage.
There are no pads under the number three, so I have assumed the pad nearest the number 3 is the correct one for the negative lead.

[Macflame]

Try as I might I could not reveal a gap in the solder. So I bit the bullet and used a fine nail file to take off the remainder solder.
I then found that the what I thought was supposed to be two solder pads turned out to be 1 big solder pad that joined two traces together.
(Please see photo.).
When I tested the resistance between solder point 1 and ground on point 3 I got 1.5Ohms. When I tested resistance on solder points 2 and 3ot 2.5ohms. Is that about right?
I suppose I could cut through the traces at the points on my photo marked red, just to be sure but I am not even sure that is necessary now. lol

[_kaktus_]

Hi.


My request was special...
I think you already know why.

Basically, when you look at these elements in different offers, the vast majority of them have five leads.
Two of them are temperature measurements. The other three are responsible for preparing the connections for different supply voltages (resistance changes).

If you want to know how it works, take a look at the parallel or serial connection of resistors.
Two heating lines correspond to them.

H-B_polaczenie_zasilania.jpg (4.86 KiB) Viewed 31361 times

.
Perhaps in your case the description of the leads was made carelessly. And that's why the numbers are placed next to the leads.

[Macflame]

Thanks again _kaktus_ .

[_kaktus_]

Ohh ...

Okay, no problem.