Teac FD-55 Series, Maintenance Manual

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(2) SKA method
(a) Connect the SKA referring to item 4-2-4 and set the FD PWR switch
to the PSA side.
(b) Use two channels of oscilloscope and connect them as follows*
i) The 1st channel: SKA DOUT terminal
DC mode, 5V, 5
a
10msec
ii) The 2nd channel: PCBA MFD control TPl (Track 00 sensor), IV range
iii) External trigger: DIRECTION SELECT interface signal (Interface
connector pin N o .18) or Pin 3 of J3 (resistor
network RA1 for terminator) on the PCBA MFD
control• "
(+) trigger.
(c) Key in MB8 F". (STEP observation)
(d) Start the spindle motor by key f,5M. (MON indicator turns on).
(e) Install a work disk.
(f) Execute drive select by key H0". (DSO indicator turns on).
(g) Set the step rate and the settling time as follows referring to item
4-2-4-3.
48tpi: Step rate 6msec, Settling time 15msec
96tpi: Step rate 3msec, Settling time 15msec
(h) Key in •'CO" and confirm that the TRACK indicator becomes ,f00".
t
(i) Key in "C5M. (TOO TIMING, SEEK ±5)
(j)
Measure
the timing of points A and B and the voltages VL and VH
4105