Vinyl Window Repair (sash cord and hardware)

I have vinyl double hung windows with no manufacturer name on them. The hardware (springs and metal in frame) and thin sash cord string inside the sills to hold up the window are broken on a couple of them. I'm hoping to replace the interior hardware and sash cords so it will hold correctly.

I've had no luck with companies and a couple of handymen as they need to know the manufacturer to get the right parts it seems. If anyone has some ideas on how I'd go about repairing these vinyl windows that would be great. There are no identifying markings on them as to who made them. Thank you.

Image 1 - sealed working hardware
Image 2 - hardware exposed
Image 3 - Sash cord properly connected
Image 4 - Broken sash cord

 

The hardware (block and tackle channel balance) in image 2 should have a number stamped on it near the bottom. Something like 25-3 or 23D... or similar. These are available from any number of suppliers, so the mfg of the window is irrelevant. Amazon, Swisco, Strybuc, Home Depot possibly, etc. You will just need to get the right part, when you have it, remove the sash, remove and replace the hardware, then put it back together.

you need the right style of balance, right length, right spring tension, and right clip on the end of the string. You should also be able to double check the measurements of the channel itself with the specs on the one you intend to purchase.