Led And Ptx Assemblies; Diskette Speed; Service Check - IBM 5114 Maintenance Information Manual

LED And PTX Assemblies
160
DISKETTE SPEED
Service Check
1. Insert a diskette. (Ensure that the diskette drive
cover assembly is closed.)
CAUTION
The PTX, LED, or drive card can be damaged if
the incorrect test pins are jurnpered.
2. Install a jumper from. (-head load) to
e
(ground) to activate the head load solenoid.
3. Use a Tektronix 453, 454, or a similar oscilloscope
with xl0 probes and set up an oscilloscope as
follows:
4.
2-46
Switch
Channel A sweep mode
Channel A level
Channel A coupling
Channel A slope
Channel A source
Trigger
Mode
Channell volts/division
Channel 1 input
Times per division
Connect the channel 1
probe to
0
(+index)
Setting
Normal
+
DC
+
Internal
Normal
Channell
1.0 V /crn
DC
20 ms/cm
Observe an index pulse width of 1.5 to 3.0 ms
0
occurring every 166.7
±
4.2 ms
e.
Pulse
amplitude should be between 2.4 and 4.2 Vdc
G.
5.
Remove the jumper.
6. Remove the diskette.
Diskette Control Card
16
o
00
140 00
Diskette 1
~
V~, ..
~.:~
Voltage~~
~:
~
Diskette 2
TPB-l
oj~
8528195 or 4178068 TPA-l
I~--+---+----I~~
e
L~
...............
~