high pitched noise during cassette play?

i am looking to help an 87 year old senior legally blind with macular degeneration. she has a general electric model 3-5282B battery operted stereo radio cassete recorder that she listens to everyday - it cannot be replaced because she cannot learn the "new" buttons. the tapes play but include a high pitched noise - the radio function works fine (with no noise, so it can't be a speaker problem). Any advice is appreciated - this is one that will bring you great karma if you can help identify what needs to be replaced/lubricated to stop the squeal