output in the high region and dropout (some parts of sound not reproduced) are typical symptoms. It is therefore recommended to clean the heads periodically before recording and playback to avoid such troubles.
2) Capstan and pinch roller
Buildup of magnetic particles and dust on these parts will cause increase in wow, flutter and wrapping of tape on the capstan. Thus, these parts must always be kept clean. Cleaning is done with cotton buds moistened with fluids prescribed or recommended for tape recorders and especially the heads. Never use lacquer thinner, acetone or other organic solvents.
3-1-2. Demagnetizing
The REC/PLAY head becomes magnetized by extended use or when the head is touched with a magnetized object. As a result, frequency response especially in the high region will deteriorate, noise level increases, and in some cases may transfer noise to valuable prerecorded tapes. For this reason, do not touch the head with magnetized screwdriver and scissors or allow DC current to flow through the head winding such as when testing continuity with a circuit tester. Should the head becomes magnetized, demagnetize it with a head demagnetizer designed for this purpose.
Demagnetizing Procedures
1)After turning off the power of Model
2)Switch on the head demagnetizer while holding it about one meter away from the Model
3)On completing the above procedures, slowly draw the demagnetizer away from the head and switch it off when it is more than one meter away from the head. As demagnetizm in the head cannot be seen, unlike the soiled head, routine demagnetizing is necessary. It is recommended to do so at the same time the head is cleaned.
3-2. Test Equipment and Adjusting Tools
| The following tools and equipment are required for adjusting the Model | |
1) | Head height and tape contact adjusting jig | Model 9001 (P/N: 8286001000) |
2) | Torque meter |
|
| Cassette torque meter | |
| Cassette torque meter | |
3) | Mirror tape cassette | |
4) | Test tape |
|
| Speed / Flutter (3 kHz) | Model 9152 (P/N: 82660022000) |
|
| Also 3150 Hz test tape for Wow & Flutter measurement is |
|
| recommended. |
| Reference playback level | |
| Playback frequency response | |
5) | Blank tape | |
6) | Audio oscillator | General type |
7) | Frequency counter | General type |
8) | Bandpass filter | General type |
9) | AC voltmeter | Stereo type is recommended. |
10) | Oscilloscope | General type |
11) | Wow & Flutter meter | General type |
12) | Distortion meter | General type |
13) | Frequency counter | General type |
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