Long time since I've done any, but Leyland SDM used to carry pretty much all the bits you might need at reasonable price/quality balance. Tools - nothing specialist, nothing you're unlikely to have in a normal toolbox.
There are bound to be guides online, but
IIRC any of the decent DIY books (Readers Digest or whatever) have sections too.
Which cord do you need to replace? Lower sash is easier as you can do it without full removal (upper sash you'll need to remove the lower one first).
Long time since I've done any, but Leyland SDM used to carry pretty much all the bits you might need at reasonable price/quality balance. Tools - nothing specialist, nothing you're unlikely to have in a normal toolbox.
There are bound to be guides online, but
IIRC any of the decent DIY books (Readers Digest or whatever) have sections too.
Which cord do you need to replace? Lower sash is easier as you can do it without full removal (upper sash you'll need to remove the lower one first).