This thread covers the repair of the SONY M-1000 micro-cassette recorder. PARTS YOU WILL NEED: Belts kit: https://www.ebay.com/itm/324160248797 NOTE: Drill bit diameter needed is likely 4mm, but given long time has passed since I did this repair it's better to double check for yourself. It needs to be just a bit larget than the hole. Apart from the normal belts replacement, there are 3 additional steps that need to be done to really fix this one properly: - repair the broken gear on the flywheel (not doing it with render a clicking sound very audible in recordings); - lubricate the motor top bearing and capstan bearing; - clean the flywheel groove and motor pulley groove of any belt residue (it may be necessary to sand it); - clean the switches and potentiometers with contact cleaner; STEPS: 1. You need to remove the outer casing. The metal part of the casing slides out towards the play/rec buttons after screws are removed; 2. Remove the plastic part near the jacks; 3. Remove the tape sticking the wires to the PCB and tilt the PCB after removing its screws; 4. Remove the flywheel retainer plate; 5. Remove the belt and the flywheel; 6. Remove the counter assembly by removing its screws. It is recommended you lubricate the shaft of the counter assy as shown in pictures before installing the new belt; 7. After installing the new counter belt, counter assy can be reinstalled; 8. Add some oil to the motor top bushing while moving the shaft up and down, so oil gets inside; 9. Clean the pulley's grooves from old belt residue; If sanding is needed, power the unit on and keep a twisted small piece of sandpaper (800-1000 grit) inside the grooves until they have no residue left; Clean with IPA after; Chances are some sandpaper residue will fall under the pulley: clean that with a coton swab and IPA. 10. Remove the white gear on the flywheel and enlarge its hole with a drillbit. Fit on fywheel should be a tiny bit loose, as glue will occupy the remaining space. 11. Glue the gear to the flywheel, while keeping it pressed with a pair of pliers (covered in electrical tape) until glue dries. Final result should be equal distance between all teeth of the gear as shown in picture. 12. Oil the capstan bottom part and reinstall the flywheel and belt; Make sure to clean the capstan and pinch roller of any oil residue before playing a tape ! 13. Put grease on top pin of the flywheel and reinstall its retaining bracket; 14. Clean the volume potentiometer and REC/PB switch witch contact cleaner; 15. Reinstall the PCB and the outer cover;
Hi Valentin. Thank you for this excellent tutorial with great photos of your Sony M-1000 rebuild. What kind of glue did you use to repair the broken freewheel gear? My Sony M-1000 has the same problem, plus the belts are stretched and hardened, but they aren't sticky, unlike what's happened with other cassette players I've rebuilt before. Thanks again for everything. Best regards from Spain. David Boal de la Flor
Cyanoacrylate super-glue is what I used to glue the gear to the shaft. Roughening the metal surface with 800 grit sandpaper is a good idea to make the glue grip better.
Hello again. I was thinking of using two-part epoxy resin glue, since I thought cyanoacrylate wouldn't work well with the nylon gear because it would make it more brittle. If it worked for you, I can try it. I'll sand the metal part of the freewheel with 800-grit sandpaper, as you suggested, so the glue adheres better. I'll keep you updated on the repair's progress; hopefully, the belts will arrive soon. Thanks so much for everything. Best regards.
..., the flywheel, I meant to write in the previous message and in this one; I apologize for my double mistake...
Two part epoxy resin is too thick for these repairs in my opinion. Cyanoacrylate glue works just fine if the surfaces are roughened before. The inside of gear is already roughened from the drillbit and the brass you do with sandpaper. It's also important to clamp the gear until the glue cures, otherwise there will be a gap between the teeth where the crack is.
Hello again, thank you very much for your reply. I'll use cyanoacrylate instead of the two-component epoxy resin glue. And yes, I'll use a plastic clamp to ensure the gear tooth module is aligned with the rest, so there won't be any problems. If it's not aligned, it could cause noise and the gear might break again. Thank you again for everything. I'll keep you updated on the repair progress. Best regards.
