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7901A
5-26.
PERFORMANCE TESTS.
5-27.
Disc drive performance is tested following initial
installation or upon completion of any maintenance
requirements. To test the unit proceed as follows:
a. Press the front panel POWER switch. The power switch
lamp and DOOR UNLOCKED lamp on the front panel
will light.
b. Press the front panel LOAD switch. The DOOR UN-
LOCKED lamp will go out. After a 30-second delay,
the DRIVE READY lamp will light.
Note:
If
the DRIVE FAULT lamp lights, or if
the DRIVE READY lamp fails to light,
refer to the troubleshooting procedures in
paragraph 5-49.
c. Run the disc drive diagnostic software program (HP
part number 13041-60001) to establish whether the data
read/write functions are being performed properly.
5-28.
ALIGNMENT AND ADJUSTMENTS.
5-29.
Disc drive alignment and adjustments are per-
formed after repairs are made, or to optimize performance
after long periods of use. Procedures are included for
adjusting the +5-volt regulator, encoder plate clearance,
encoder clearance, encoder parallelism adjustment, encoder
alignment, servo adjustment, head alignment, sector circum-
ferential and belt tension adjustment.
ENCODER
PLATE
7901-25
Maintenance
5-30.
REGULATED +5 VDC SUPPLY.
5-31.
Prior to performing an adjustment or alignment
procedure, the output of the +5-Vdc regulator on servo
amplifier/regulator assembly A4 should be checked and
adjusted using the following procedures:
a. Set the LOAD switch to the released position. Remove
the disc cartridge. Remove drive power by setting the
POWER switch off.
b. Remove the disc drive top cover and cartridge receiver.
c. Press the POWER switch on.
d. Connect digital voltmeter to A4TP7. Adjust A4R1 for
an indication of +5±0.1 volts.
5-32.
ENCODER PLATE CLEARANCE.
5-33.
The
encoder
plate
clearance adjustment
is
normally required
if
the encoder plate is replaced for
maintenance purposes. To adjust the encoder plate clear-
ance, proceed as follows:
I
CAUTION
I
Exercise
caution when touching the
encoder glass. Excessive pressure might
break the
glass.
a. Loosen the encoder plate clamp screws. (See figure
5-2.)
0,030 INCH
FEELER GAUGE
Figure 5-2. Encoder Plate Adjustments
5-7
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