Nakamichi 481 Service Manual - page 8

7

(3) F.F. or Rewind Mode 

By pressing the F.F. or Rewind Switch, it comes either to 

F.F. or Rewind mode. The only difference of these two 

modes is that one is to turn the Reel Motor reverse and 

the other to transmit the torque against the Reel Hub onto 

the take-up side or to the supply side. Brake is re leased 

at this stage and the Reel Motor begins to turn F.F. or 

Rewind.

2.2. Amp. Circuits 

2.2.1.  Playback Eq. Amp. Circuit 

Fig. 2.2.1 shows the playback equalizer amp. circuit. 

Fig. 2.2.2 shows its system diagram, and Fig. 2.2.3 shows 

the time constant of equalizer. 

Playback Head is connected to the input of this circuit. 

Amplifier, which is composed of Q1

01 and Q102, is an 

equalizer amplifier and its time constant is shown in Fig. 

2.2.3. R111, R112, L1

01 and C109, which consist of a 

peaking circuit, compensate playback head gap loss and 

improve frequency response at high. L1

01 and C186 

compose a bias trap circuit and prevent bias leakage from 

playback eq. amp. circuit. 

Playback eq. amp. gain adjustment should be performed 

so as to obtain 100 mV at TP1

01 (TP201) by adjusting 

VR1

01 (VR201) during the course of playing back 400 

Hz Level Tape (DAO9005A). Eq. Switch (70 us/1 20 us) is 

connected to the playback eq. amp. circuit and the overall 

time constant of playback eq. amp. circuit will become as 

follows: 

(4) Pause 

Mode 

Press the Pause Switch to make it to Pause mode. In 

changing it from Stop mode to Pause mode, the Brake is 

first released, then the Head Base is latched, and again 

the Brake works. 

At this stage, the Reel Motor would not turn with the 

Pressure Roller being apart from the Capstan, and the 

tape would remain still. 

Tape SW 

Eq. SW 

Tape 

ZX 70us 

Nakamichi ZX 

SX 70us 

Nakamichi SX, TDK SA, Maxell 

XL-II 

Scotch Master 70 us 

EX 

   120us 

Low-Noise High-Density 

(including EX, EXll, TDK AD, 

Maxell XL-l, Scotch Master 

120 us) 

70 us 

Nakamichi EX, EXII