Test Points; Tp1 And Tp2 Pre-Amp; Tp3 Ground; Tp6 Erase Gate - Fujitsu M255XK Customer Engineering Manual

3.3 TEST POINTS
Connectors and test points on the main circuit card are identified in Figure 3-8
and explained in the following paragraphs.
Con1ectors:
Jl Interface
J2 Power Supply
J3 Spindle Motor
J4 Stepping Motor
J5 LED Connector
J6 Door Lock Solenoid
J7 Write Protect, Index
J8 R/W Heads
J9 Track 00, Disk-in
JI0 Head Load Solenoid
Test Point FlD!tions:
TPI Pre-amp
TP2 Pre-amp
TP3 Ground (0 VDC)
TP4 Differential Amp
TP5 Di fferential Amp
TP6 Erase Gate
TP7 Track 00 Sensor
J8---~-+-
Lot NO.
-t---+--Jl0
-+---Jl
,..---------, r--"
I
Draviag
No.
ISSUE
I
I
I
I
I
I
-+--32
L __ _
o
Figure 3-8 Location of Connectors and Test Points
3.3.1 TPI
and
TP2 Pre-Amp
Figure 3-9 shows typical TP1/TP2 Pre-amp Waveforms. Use these test points to
monitor the Read/Write head output. The pre-ampll fier has two phase inverted
(180
0 )
outputs that ranges from several tens to several hundreds of mUll volts peak-
to-peak.
For accurate waveform monitoring, a dual trace (2-channel) oscilloscope should be
used (with one channel set to the inverted ADD input mode) to monitor TPI and
TP2 as one waveform. The oscilloscope can be grounded at TP3.
TS-021-0n087 ••• 01 3-11