Telex Copyette User Manual
Is this a newer X-Gen or the older mono ones? Coming from the thrift store 90% of the problems are that tape machines regardless of the manufacture have probably never been serviced. There can be sticky or nonexistent belts, gummed up motors,dry gears, pinch rollers with 20 years of residue, heads that have never been demagnetised or cleaned, smoke residue and so on.
Telex was picky about the tapes used, some cheap tapes would actually damage the heads. Manuals are available online for these machines. After so many hours of use, the telex needed servicing, when your doing high speed dubbing, (16x) crap builds up fast and so does wear on the heads hence the warning to use high quality tapes. Seems like it's an older model, no buttons on it, just a 3 way switch on the right side (stop, rewind, and copy), and a switch to dupe side a only or both side a and b. Opened it up and everything looks to be in good shape. All parts are moving, belt is intact and in good shape, pinch rollers seem ok. Don't have a demagnetizer, so I can't check that bit.
User Manual Template
Would that have anything to do with getting no audio to transfer? When i ran it, the tapes both finished and rewound without issue, it's just when i popped the duped tape into my deck to check if it worked, I got nothing. The machine is even in good shape cosmetically (plastic and factory instruction sticker still on protective plate on front). V puzzled by this one.