Adjustments And Verifications; Motor Speed Verification (Index Period); Write Protect Verification; Head Output Verification - Panasonic JU-475-4 Service Manual

9. ADJUSTMENTS AND VERIFICATIONS
9.1 Motor Speed Verification (Index Period)
(1) Insert a diskette, run the motor, and clamp. Refer to the index period column of Table 8-1.
(2) Step to the specified track.
(3) Connect a frequency counter to the INDEX signal: TP7
(4) Check that the frequency counter readings meet the specifications of Table 8-1.
9.2 Write Protect Verification
(1) Check that the exerciser's write protect lamp goes on and off as a diskette is inserted and
removed as specified in the table below.
Diskette with write protect Diskette with write protect
hole open hole closed
OFF ON
(Not write protected) ( write protected)
9.3 Head Output Verification
Use a new diskette if possible to identify head failure for this check.
(1) Insert a good diskette.
(2) Run the motor.
(3) Step to the track specified in the output level column of Table 8-1.
(4) Connect the oscilloscope probe as specified below.
CH1 CH2 EXT
· : · : I I \ ~ ~ I ~ I ! : I I ! I : I I ~ ~ : j l l ~ I ~ I ! \ : ~ : \ . I : : . I : ~ 1 1 1 1 : ! ! : . :
Invert channel 2 and select the Add mode.
Set vertical deflection to 10 mV/division and horizontal deflection to 20 ms/division.
(5) Write 2F (all "1"s) on the entire circumference.
(6) Check that the average output level meets the specifications of Table 8-1.
v -
Vmax + Vmin
average -
2
If it does not meet the specifications, refer to Item 7 of the Trouble Analysis Table.
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