HP HP-97 - Page 147

- CORVALLIS DIVISION
KA ackarn 97-101
SERVICE NOTE e s
.
S
edes:
(...continued)
upersedes
b. Bent worm gear/bad couplers.
c. Bad drive roller and gear.
d. Bad motor bearings.
Lubrication is done by removing the motor assembly from the card
reader and applying mo]y-disu]fidé**on the thrust bearing (the hole
the tip of the worm gear fits into). The motor is reinstalled and a
small amount of lubrication is applied to the worm gear. This
should quiet the assembly, if not, check for bad components. Once
the noise is at an acceptable level, the motor current must be
adjusted. Hook the motor to a power supply set at 3.5V and measure
the current drawn by the motor. By adjusting the eccentric cam on
the drive roller and the motor mount screws, the current can be
minimized. Using a card held in the unit, the eccentric cam can
be set to give adequate card pull. This current should be around
180 + 20 milliamperes.
I. Next adjust the motor speed by recording a card and after dipping
it in Magna-See, check the record length against a speed scale.
Adjust the motor speed by selecting a different R1 resistor from
the Tist on page 4-25 of the Service Manual. Each resistor's
range is about 3 mm of record length on the card. The card reader
should now be repaired and a final checkout should be done by:
i. Read a program.
ii. MWrite this program on a blank card.
jii. Read the card that was written on.
iv. Try to write on a protected card. ("ERROR" should result).
v. Magna-See the card that was written on and check the motor
speed.
(continued...)
For more information, contact the Service Engineering Manager, Corvallis Division—1000 N.E. Circle Blivd., Corvallis, Oregon 97330
Telephone (503) 757-2000 ¢ TWX # 510-596-0683
Printed in U.S.A.