Pioneer Cassette Deck & Reel to Reel Repairs
This was showing a few problems; the left meter was not working, the recorded levels were not equal on playback, there was about 1 cm of play in the reel motors and the tape counter didn't work. Solutions as follows; the record pre-sets needed adjusting, the reel motors needed dismantling and the spring washer refitting in the correct position (suspect the reels had been bashed in transit) and the counter belt needed replacing, after that a newish\second hand meter was ordered. Noticed although the recordings seemed okay the legs of the transistors in the record cct were corroded so replaced them before they gave any recording problems.
This would trip the auto stop then do nothing. A pivot that the arm operates had seized. Fast forward & rewind were non existent as the idlers were slipping, the rewind one seizes up and is a pain to free. It also needed a new capstan belt which is around 80 mm diameter. The mechanism is the same as the CT-F7171.
This one needed new belts, played back fine after setting\call the levels.
There was no tape movement in play, rew\ff were okay, the capstan motor was cooked, as were the 4 driver transistors, which looked to have been replaced at some time, replaced the motor and transistors and it worked okay, new belt was fitted while it was dismantled, and the pinch wheels replaced as they had started to go sticky.
Top of the range (£600) cassette deck from 1978. The o\p had noise on RH channel in monitor mode(play back). The input transistor on the playback board was noisy. It runs at extremely low collector current to keep noise down and very high gain, this tends to cause the junction to become faulty in some way as the 3rd transistor was a simple emitter follower. I swapped them around and used an available low noise for the emitter follower. A new belt was also needed, which was obtained from the USA. $16 for a full set, yes they are still available. The RH pinch wheel needed changing, it had become barrel shaped, but couldn't find a source, so set to with a small file and a scalpel blade and quite a lot of patience to re-profile it. Another fault became apparent which was it would stop intermittently during playback this was the 'cassette in' micro switch going high resistance, soaking in WD40 sorted.
Pioneer CT-676 (1991)
The cassette draw had come off its locating slot and was loose plus the motor ran at full speed. An exact replacement from CPC sorted, easy to change, 3 screws hold the plate which can be removed without dismantling further.
The reel motor had lost its power\torque and is no longer available, as the deck was in good condition otherwise a solution was required, a capstan motor minus the speed reg was fitted into the original housing, the original motor was a constant speed with centrifugal speed control, putting 3.9ohm resistors in each supply to the motor kept the speed close to the original.
This cassette deck from 1974 would stop after 5 seconds. The encapsulated auto stop switch wasn't being 'switched' when there was tape movement, tapping the case of it sorted, suspect there is a reed switch with a rotating magnet inside, it's on top of the mechanism behind the cassette housing.