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15.9. 2
Machine Reel Brake
Adjust the machine reel brake with the potentiometer so that the reel is stopped
when about 1/16" of tape is on the reel after rewinding from a full reel of tape with
the machine-reel sensing-arm switch adjusted as indicated above.
15.9 .3
Time Delay
Adjust time delay so that it runs for about 1 -1 /2 seconds after the machine reel
has stopped after a high-speed rewind.
15.9 .4
Magnetic Clutch Adjustable Resistors
Adjust resistors in the resistor box so there are 30 + 5 volts across each clutch
when it is energized through vacuum switches.
15.9. 5
Adjustment of Photo Cell Output
The photo light sources are adjusted with the lk-ohm potentiometer across R14.
This potentiometer is located on the rear of the relay gate. Adjust the potentiometer
until the total voltage across the two bulbs in the photo cell assembly is 2 . 5v (+0 - . 2v)
when unloaded.
The voltage across any one bulb should not exceed 1.5 volts. Replace
the photo cell if it does not conform to the following:
1. Dark resistance 600 K to 2 .4 M ohms.
2.
With the light source adjusted as above, the DC change in level of the photo
cell output (from tape under the photo cell to reflective spot under the photo cell) must
not be less than 10 volts.
cell.
NOTE: One of the pins on the photo cells may*be quite rough on the end.
file these pins.
The cells are evacuated through them and filing may destroy the seal.
Do not solder photo cell terminals without removing the photo cell.
15. 9. 6
File Protection Device
Adjust this device by loosening the relay mounting screw s and moving the relay
on its bracket so that a reel with an insert depresses the plunger sufficiently for the
A points to make with at least . 005" overtravel. With the relay energized, there
should be at least . 060" gap between the plunger and the file protection ring, and B
point should make with at least . 005" overtravel.
15.9. 7
Tape Break Light Testing
The tape break light and circuit may be checked in the following manner:
1. Unload the unit and remove the reels.
2. Place a piece of card across the read-write head and tape cleaner.
3.
Hold the reel arm up.
4.
P ress the load-rewind button.
5. After the file reel hub gets up to speed, remove the piece of card.
reel hub should stop immediately.
Measure between ground and the white lead on each photo
Tighten the reel holding nuts.
60
Do not
The file
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