IBM 5110 Series Maintenance Analysis Procedures page 172

B C
1 1
KEYBOARD MAP
PAGE 2 OF 7
005
- Measure +8.5 Vdc and +5.0 Vdc at the A 1
board (see MIM 255).
Are both voltages in tolerance (+7.8 Vdc to
+9.3 Vdc and +4.6 Vdc to +5.5 Vdc)?
Y N
006
Go To Map 0700, Entry Point A.
007
Bad keyboard PC board (see MIM 251).
Check/replace Z4 (keyboard) cable (see Map
0210 and MIM 206,255).
008
- Press the
Q
key then the P key.
Did anything (P,
Q,
*, ?, invalid key, etc)
appear on the display?
Y N
009
-Probe H2-U12 on the A 1 board (-keyboard
strobe).
(See appendix B, the general logic probe, in
the 5110 MIM).
Is the DOWN light on?
Y N
3 3
010
-Probe H2-U12 on the A1 board (-keyboard
strobe).
- Press and hold the P key.
Is the DOWN light on?
Y N
011
Bad keyboard PC board (see MIM 251).
Check/ replace Z4 (keyboard) cable (see
Map 0210 and MIM 206,255).
o
E F
F
MAP 0600-2
012
-Release the P key.
-Probe H2-U06 on theA1 board (-interr req 3).
Is the DOWN light on?
Y N
013
-Probe H2-U06 on the A1 board.
-Observe the DOWN light while sequentially
pressing keys.
Does the DOWN light come on?
Y N
014
Bad H2 (base I/O) card.
Bad J2 (processor) card (see MAP 050 for
jumpering).
015
Bad J2 (processor) card (see MAP 050 for
jumpering).
Bad H2 (base I/O) card.
Bad CMD key module (see mim 253).
Bad keyboard PC board (see MIM 251).
Check/ replace Z4 (keyboard) cable (see Map
0210 and MIM 206,255).
016
- Disconnect the keyboard cable at Z4.
-Probe H2-U06 (-interrupt req 3).
Is the DOWN light on?
Y N
3
G
017
Bad keyboard PC board (see MIM 251).
Check/ replace Z4 (keyboard) cable (see Map
0210 and MIM 206,255).
01JAN79
EC 836600 PEC 835541
MAP 0600-2