Light-Emitting Diode Output Service Check - IBM System/34 Maintenance Manual

25-810
LIGHT-EMITTING DIODE OUTPUT
1.
2.
3.
4.
5.
6.
42
SERVICE CHECK
Set Power to I (operator panel).
Connect the negative probe of a multimeter to the
ground test pin
G
on the diskette drive control
card.
Set the multi meter scale to 5 Vdc and connect the
positive probe to the 53FD light-emitting diode
voltage test pin
e.
Check for a voltage level of 1 Vd.c to 2 Vdc.
Move the positive probe to the 33FD
light-emitting diode voltage test pin
O.
Check for a voltage level of 1 Vdc to 2 Vdc.
14 1
16 1
HCP
100 0 0 0 0 0 0 0 0 0 0 0 Q
I
10 0 0'0 0 0 0 D 0 0 0 0 0 0 D D
I
TH P
HOTP
0
H1TP
0
Head Cable Connector
TPB14
53FD
LED
Voltage
TPA12
33FD
LED
Voltage
Auto Test Connector
00 0 0
0 0 0
25-810
TPA6
Ground
TPB
TPA
r-"
I
\".
/
(~
'-.
..
---'
(~'
'-,
....
_./.