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E. Set up the oscilloscope, as follows:
Voltage: 2 volts per division
Time Per Division: 20 milliseconds
Trigger:
N e g a t ive, Channel A, R33
For the TM848-1 single-sided drive, trigger off of R33. For the TM848-2 double-sided drive,
trigger off of Test Point 12, with the exception of azimuth, which must be triggered off of R33
(see Figure 2-1).
00 DSI
Ib 0
ob DS2
2b 0 OODS3
3b 0
OODS4
4b 0
MC3
3
MCI
MC200
S 2 00 0
5 1
S2
0 0
0
C 0
MC4 o
OTPS
50
TP T
OTPIO
0
0 DL
TPS
F. Adjust R133 until a reading of 166.667 milliseconds is achieved from leading edge to leading
edge of the index pulses.
G. If the drive motor's speed cannot be adjusted, see Section IV, Troubleshooting Guide.
2 .2
C A T S E Y E ALIGN M E N T CH EC K AND ADJUS T M E N T
The Cats Eye (C. E.) alignment procedure locates the read/write head at the oroper radial distance
from the hub center line, ensuring that the track location is accurate(seeFigure 2-2). This adjustment
is necessary only after servicing or if diskette interchange problems are suspected.
Note
TP5
f
TP40 0 0
PTS
ALTERNATE TEST POINT, INDEX TRIGGERING
R33
OO Y
NP
00 DS2
Ds1
WP
TPII O
Q
O P 1 2
P2
P 3 PI O
P I
PI I P 12
Figure 2-1
Circuit Board Assembly
2-2
M3
2SOO
DCOO
0 M4
00
Rl
0 RM
0
00
00
14 Cb
IX O
M I
M2
8
00
IZ
II
P14
PS
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