IBM 3278 Series

M
5
MAP 01
Terminal Failure MAP
PAGE 6 OF 13
026
Plug line power cable in and switch unit on.
Verify
voltage at J4 on the low voltage power
supply between pins 1 and 4 for 48 volts AC. (See
Figure 4-11).
Is the voltage correct?
1
:27
Reverify power source outlet. If outlet is good,
exchange ferro.
028
Verify DC voltages:
(DC Common is at C3 - (minus)
on low voltage
power supply
(Voltages are ± 10% except +8)(See Figure 4-11)
+5 at fuse F6.
+8.5
at fuse F3.
+44 at fuse F5.
-5 at 010/PS1-J3-3.
-12 across Cl (F2).
-44 at 010/PS1-J3-1.
+8V+/-lvolt 010/PSI-J2-2,
. (derived from +8.5V supply).
Are all voltages correct?
N
029
Switch unit off.
Remove analog card.
Switch unit on.
Verify voltages
as shown in preceding step.
Is one or more voltages incorrect?
11
977
N P Q
2·01·6
SY27-2510-6