IBM System/360 2050 Maintenance Manual page 110

Operation Control Check
1. Set channel control switch to selector channel
position, channel selector for correct channel, and
rate switch to single-cycle position.
5. Press system start pushbutton; observe a -350ns
pulse.
6. Set address key 8 down (Hold DTC); press enter
and start pushbuttons; point should go down until address
key 8 is reset.
2. Set the following JAR keys down and check for
correct results; press the enter key for each and then
reset each key off.
Singleshot Adjustment
JAR Key Result
30 Select In
29
27
Service In
Address In
26 Poll and Select Out (Do not reset)
31 Operational In (Do not reset) and Operational
In Test
28 Status In and Command Out
3. Reset Channel Control to normal position.
DTC Hold Check
1.
Add the following jumpers:
B-B2G4D04 (KE311AB4 tie I/O routine on)
to ground
B-B2K5B09 to ground if channel 1 under test
B-B2C7D07 to ground if channel 2 under test
B-B2C7B03 to ground if channel 3 under test
2. ROS repeat on address OBO.
3. Set rate switch to single-cycle position.
4. Scope the following points on the channel under
tests:
Channel 1 B-B2K7D04 (KE451)
Channel 2 E-C3L2D06 (KE451)
Channel 3 E-C3L2B12 (KE451)
Name
Page Location
IF
Line
Check
GRIOI N305B02
Select In Gate GRJOI N3D5002
Start IF POLL GR\21 M4H7002
IF RESET GS151 M4H7802
FIGURE 106. SINGLESHOT TIMING PROCEDURE
Timing
iso•
H
o.
b.
c.
d.
iso· (-)
a.
b.
c.
d.
iso• (-)
o.
b.
c.
B
U>ec (-)
a.
Adjust singleshots as shown in Figure 106; sync scope
on internal.
Selector Channel Clock-Stepping Procedure
The following will allow clock 3tepping through the
start 1/0 CCWl, CCW2, unit select, end update, and
interrupt routines. This procedure is to be used in
conjunction with IOP201, 202, 211, 209, and 210,
respectively. A mixture of channel clock stops and
ROS single cycle is used to step the routines and al-
low scoping at each stop. The channel stops at the
end of the indicated clock cycle; therefore, all con-
ditions on the !OP pages, following a clock cycle and
up to the next clock cycle, have been completed. Fig-
ure 107 shows a block diagram of the routines that
can be stepped by this procedure.
To prepare for selector channel clock stepping,
proceed as follows:
1. Mount a scratch tape on a tape drive. Make
sure it is not file protected.
2. Key in the following program:
Address
0000
0004
0048
Data
FF040000
00000300
00000400
Procedure
Set sel chan switch to desired channel and
set monuo! op switch to .>el.
Set keys 27, 29, and 31 down (addr in, svc
in, op in).
Jumper
K4J6D06
to
M4E7B02.
Press ENTER; the single shot should be firing
continuouily; obse,ve scope and adjust top
potentiometer.
Set se! chon switch to desired channel and
manual op ~witch to sel position.
Jump«
N3D5B02
ta
N3D05B07. Jumper
K4J6D06 to M4E7B-02.
Ser keys 27, 29, 30, 31 down {addr in, svc
in, sel in, OP IN} and depress ENTER.
Observe pulse on scope and adjust bottom
pctentiometer.
Set manual op switch to off position; set rate
switch to process pc»ition; press reset and start
pushbuttons. (Ensure that channel clocks are
running)
Jumpe' K4J6006 to M4H7BOB and M4f6BOB
to ground.
O~erve
puhe on scope and adjust bottom
potentiometer.
Pren RESET repeatedly and ol::6erve pulse on
scope; adjust top potentiometer. (Place check
Comments
Restart PSW
CAW
control switch in any position other than disable.)
Service Checks, Adjustment and Removal Procedure (3/71) 109