Jim,
You are delving into some real important and sensitive areas of the printer. It is very important to be sure that the cables are definitely the problem. You didn't mention what the printer was doing and why you wanted to change them. It would be wise to discuss the exact problem with some of the very talented forum people before going into the problem of changing the cables. Yes, they can be changed if you are savvy to all the parts that have to be removed to do so. Also, are positive that is the problem. Unless they are visibly damaged or bent some way, it may not be the ribbons.
As far as the cost, I haven't purchased any even if they are available. It may be cheaper to find a junk printer and make one good one out of two. Even the new printers are not too expensive. I have been using and repairing inkjet printers for many years and never had one of these cables to be a problem. It is possible they could be loose and need resetting etc.
If you care to, post the information as to what the printer is doing and what has been done to correct it if anything has been done.
I'll check back occasionally to see if you have posted any new information.
Good luck.