Nakamichi Cassette Deck Repairs
This one would stop at random. The reel idler was of the gear wheel type so I couldn't blame that, the motor drive IC was running hot but fitting a heatsink on it didn't prevent it and the reel motor just looked at me denying all blame. Eventually found the switches on the mode cam needed cleaning.
This was reported as not working on one channel. I tried it and it seemed okay although one channel was reluctant to record. After cleaning the switches, pots and the pinch wheel it worked well.
Nakamichi 1000 II
I received this deck through the post and at first it wouldn't operate the transport controls. Turned out to be loose and bad connections on the plug in connectors inside. The original fault was the record head calibration didn't work, that turned out to be the right channel record head being open circuit.
Nakamichi BX-2 (1983)
After repairing the usual idler (no ff\rew or play) between the reels on some cassettes one channel(left) was lower than the other after tweaking the rec\playback level. I found the metal plate behind the cassette that covers the cassette workings wasn't located in the guide pin slots (doh) and had to set everything back to the correct levels.
Nakamichi 1000 ZXL
This had several faults, would not auto calibrate, sound was distorted, the filter switch would cause the sound to disappear when operated, after checking it over the power on sequence would not operate correctly, so I gave up. Life is too short for these faults and B&W won't touch them!
Nakamichi 700 Tri-Tracer
This wouldn't record on one channel, inside is a statement of quality and over engineering, but you can never allow for bad connectors after 30 years or so, there are plug in daughter boards to the main PCB these had bad connections, the tape monitor switch worked intermittently switch cleaner sorted.
Needed the tray stop\rotate position setting and the feedback pot repositioning to align it correctly.
Nakamichi Cassette Deck 2
Similar to the Pioneer 676, motor was faulty used an 'avmt10' from CPC.
No play mode. The transistor that switches the capstan motor on had gone o\c.
There were several faults with this deck; 1)the idler for ff\rew needed the surface hardness removing (no ff\rew or take-up torque) new ones are still available, 2)the o\p and record sliders were very noisy, 3)one of the mode switch contacts required opening slightly as it wouldn't go into pause. Note the fader 'up' LED is lit normally and is only able to alter in record mode, I spent ages trying to find a none existing fault! (thanks to a guy in USA for advising).
This one was destroying tapes. The left hand pinch wheel was out of alignment because the pivot pin was being extracted from the chassis by the spring tension, ie it was loose! Dismantled and fixed it in position, the cause was the pivot bush partially seizing and rotating the shaft, needed the heads realigning too, made excellent recordings after.
Nakamichi 550 Portable
No ff\rew, there is a 5.6 ohm resistor in series with the motor supply when these are selected to limit the current, it was o\c, the tape speed was varying, this model uses a pulse width cct to vary the motor voltage to control the speed but it was the motor bearing that needed lubricating in this case, the ff\rew uses a normal DC supply.