[cctalk] TK50/70 Repair

Fellow cyber-antiquarians: I have been fussing around with a TK70 for some hours now. It goes ready when powered up without  a cartridge, takes up the leader fine when a cartridge put in and the flat, but then dithers forwards and backwards, eventually flashing all its lights.  The only way to remove the tape is manually. Somebody posted that the most common problem is optical sensors, stating that there are four.  I have only found two, and cleaning them got me to the point of it coming ready, whereas it would not before. Is there anybody on here that knows of a service manual?  I see that this was considered an FRU, so maybe depot repair people had a magic bible. Once I have this fixed there is a TK50 to start on.  I hate to give up! I have a box full of cartridges to read! cheers, Nigel -- Nigel Johnson, MSc., MIEEE, MCSE VE3ID/G4AJQ/VA3MCU Amateur Radio, the origin of the open-source concept! Skype: TILBURY2591