Fostex A-8 - Demagnetization and Testing

c) Cleaning the capstan
Clean this at the same time the head is cleaned.
The same cleaning fluid is recommehded.
d) Demagnetizing of heads and tape guides
After cleaning all heads and tape guides, they should be demagnetized every
morning or before starting a new session of recording.
1) Be sure to switch off the recorder.
2) Have all tapes at least 5 or 6 feet away when demagnetizing because the
demagnetizer's magnetic field will erase them.
3) Slowly wave the tip of the demagnetizer up and down in front of each head,
then, slowly move it away (Slow movement is recommended as any abrupt motion
can remagnetize the head). Like a turtle, take your time to repeat the pro 
cess on the other heads.
After you finish work on all heads, draw the demagnetizer an arms-length away
switch it off, and unplug the cord.
e) Testing the brakes
See Item 6.3, b) Brake torque, page 32.
f) Testing the pinch roller pressure
See Item 6.3, a) Pinch roller pressure, page 31.
g) Testing the amplifier
Thread a blank tape on the Model A- 8 and record a IKHz, 0 VU signal. While the
machine is in the record mode, check to see that the meters read 0 VU of, first,
the channels 1^4 group, then the channels 5^8 group, by selecting with the
GROUP button.
If adjusting is required, refer to Item 6.4.
Rewind the above recording to the beginning, reset the RECORD TRACK to SAFE, and
put the machine in the PLAY mode. The VU meters should all read 0 VU.
Record a 45Hz through 18 KHz signal and check the overall frequency response with
the VU meter to see that it is within ±3dB .
Disconnect any equipment plugged into the INPUT, record a length of no-signal
tape, and reproduce it to check the S/N ratio. In the same way as before, re 
cording and checking is done, first, on the 1 % 4 channel group, then switched
to the 5^8 channel group by the GROUP button, and the same steps repeated.
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