IBM 727, Руководство по инструкции

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5. O PANEL BUTTONS AND LIGHTS (FIGURE 5)
Located on the reel door of the tape unit are the operating buttons and lights.
These may be operated if the door interlock switch is transferred.
Select Switch. This switch is rotary type, located in the center of the group. It
is used to set the tape unit to any one of the ten addresses. If the switch is set on
address 1, the unit is not selected unless address 1 is selected, and so forth.
Select Light, The select light is turned on when the tape unit is selected and r e ­
mains on until the selection is removed.
Start Button. Depressing the start key causes the machine to be in a ready condi­
tion if : (a) tape has been previously loaded into the column, (b) the reel door interlock
is closed, and (c) the tape unit is not in the p rocess of finding the load point (rewind or
load operation).
Ready Light. This light is on if the machine is in a ready status as described
above. Manual control is indicated when the ready light is off provided the tape unit
is not rewinding or loading and the reel door is shut.
File Protection Light. This light is turned on automatically by mounting a pro­
tected reel onto the unit. It is on if no file reel is mounted.
Load-Rewind Button. If the reel door is closed, depression of this key causes
loading of the tape into the columns and searching for the load point. If the tape has
been unloaded manually in the fast rewind section of the tape, depressing this key
executes a high-speed rewind before the above operation takes place. This button is
inoperative unless the tape unit is under manual control.
Unload Button. Operation of this button rem oves the tape from the columns and
raises the upper head assembly regardless of the distribution of tape on the two reels.
If the tape is not at load point when the operator wishes to change it, a load-point
search should be initiated first by depression of the load-rewind button. The tape in­
dicator is reset by depression of the unload button. This button is inoperative unless
the tape unit is under manual control.
Tape Indicator On Light. This light is turned on whenever the tape indicator is
turned on by external control when reaching a tape mark while reading, or by reach­
ing the physical end of tape while writing. It may be turned off under external con­
trol or by depression of the unload button.
Reset Button. This button resets all controls (except the tape indicator) and, in
general, stops any tape operation that has been initiated.
Fuse Light and Thermal Light. The fuse light and thermal light are located on
the inside of the door assembly. The fuse light is nearest the door latch and lights
when either the AC or DC fuse bail trips. The thermal light lights when the tern cop
at the top of the tube panel operates from over-heating.
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