I'm looking for advice about how to remove a window spring tab so I can solder it back together.

Our farmhouse front door is so narrow we went with a mobile home door, which has a slide up/slide down pane held in place by two spring-loaded prongs. One of the pins has broken off where the pull-tab meets the pin (thus the gap were the screwdriver blade is.

They're simple cast pins, so they should be fixable with solder, BUT I don't see how to remove the pin from the window frame so the break can be fixed. There is a return/tension spring in the lower part of the frame to the left of the pull tab, aside from that I don't see anything that suggests how to remove the pins from the frame.

Anybody with window experience know how the pins come out? Is there a clip, a retaining pin or other simple technique to remove the pin? Or am I going to have to disassemble the frame to get to the pins?

Those with sharp eyes will notice that the pins are upside-down. That's intentional because the from-the-factory configuration had the screen on the bottom and the window slide up. With a cat and occasionally dog-sitting, that was not a good setup, so the window insert has been flipped so the solid window is at pet height, and the screen is at the top.

 

Depends on the slide bolt and the corner insert. By the way it's a called a slide bolt. Some are integral with the corner piece and must be replaced with the corner. Most can be replaced without removing corner. Many different types. See SWISCO.COM and type in slide bolt. Click on any one of the types and usually there is a video showing how to remove and install the slide bolt.
I doubt you'll be able to repair the thing. You need to buy a new one. Match up yours with the many styles at SWISCO and replace. If they don't haver it. let me know. I have made several with a 3D printer.

 

On some you can see a "button" that you push in and it allows the latch to slide out. On some models there is a punch, dimple or crimp in the frame that you can drill out. Or you can pry the frame open just enough to allow the latch to pop out.

Don't bother trying to solder the old latch unless you are patient. Most I've seen are cast zinc which can be soldered but it's not easy. The zinc has such a low melting temperature you have to be careful to not melt the part when soldering. I just order replacement latches online. There are many different styles so don't click buy on the first one that looks similar without confirming it's what you need.

 

Ok, about what I expected- I'd hoped there might be a trick 'remove the tension spring and slide back, then pivot up' or something like that.

Without removing the slide bolt, I'll probably just hot glue / construction glue a plastic tab onto the hatched portion of the bolt. That window is only moved up or down as the seasons change, so kludging on a tab or just using a screwdriver is sufficient.

 

I've even drilled a small hole through the frame & aluminum sash and use a cut off nail as a pin to hold them up or down.

 

Oh, I grew up in an old farmhouse with the 'guillotine window propped up on a stick' that put the fear-of-god into you when you reached into the window.
So, I'm quite familiar with the 'creative' fixes for windows.
For this application, there is a 2-flange channel that the bottom-of-the-window-pins run in, so I could use a bold cutter to remove the bolt end and then use double-headed nails as pins to set window height.