[DaveWM]

you can transplant the center part to an existing knob, there is a spring clip type retainer, you must destroy the shaft to remove it, you do this to the knob with the broken handle, saving the numbers. Then from the donor you have to destroy the metal retainer to separate the donor shaft from the channel part.
just make sure you are only destroying the part that is already broken. I tried to see if I could get the metal retainer off, no way. you have to break the metal ring or the plastic shaft.

The idea is to save your channel indicator which matches and only use a new donor shaft with the part you turn. the reason... wait for it....

sometimes the channels don't match up, that's right it may look like a perfect match but channel 3 will show as channel 4 etc...

the D retainer is not consistent, so you can find a perfect set of knobs and have it still not be right. However the donating process worked, there is a molded in detent that locks the two parts and that is consistent, just not the actual numbering on the dial. I know cause I just went thru this on a PC with a busted knob handle.

it sounds confusing until you get the knobs in front of you.

so if you have a supply of knobs just look for a matching inside part, that way you have more to choose from.