I certainly agree with a comment that Joe Offer made regarding the cheap materials that went into the cassettes back in the 70's. I recently archived a series of superb concerts performed in Seattle in 74 and 75. EVERY ONE of these cassette had failed ... the tape had become unfastened to the end of the spool. This required me to learn how to open the case, and re-position the guide and re-fasten the tape. This is NOT an easy task. If you try this, I suggest you first put all your fingers through the pencil sharpener first .... bob