Y-E Data YD-380 - Page 29

- Connect channel 2 to PWB test point lB.
- Connect
scope ground to PWB test point G (GND).
- Connect the external scope trigger probe to PWB test
point 3.
,
Set the oscilloscope controls as follows:
INPUT COUPLING MODE
AC
VERT MODE
ADD
INVERT
(CH 2)
ON
TIME/DIV
20 ms
VOLTS/DIV
(CH 2)
20
mv
3. Insert a CE disk and turn the front lever to lock position.
4. Load the read/write heads against the disk and make sure
the Track 00 signal (Jl-26) is at Low level (0 to 0.4 V).
5. Step the head/carriage from Track 00 to 32. Obtain A/B
or B/A', the ratio between the two amplitude lobes on t·he
scope. Convert the ratio to a position on the CE disk
conversion chart. The positioning error should be within
±25 ~ (See figure 4.14.1, figure 4.14.2).
6. Step the head/carriage from track 3) to track 32 and check
the positioning as in step 5 above.
A
B
Figure 4.14.1