IBM System/360 2050 - Page 106

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No
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5elector
Channel
Malfunction
load
Progressive
Scan
Yes
Load Progressiv;:e __ Y-'-=e~s------------------------------------------------------------.,
~can throug >
another chonne I
No
Trouble.hooting
without
progressive scan
No
Check control
•witch to
CHAN STOP.
Run program.
Examine program in
the region of failure.
erun program and
stop be fore fa i I ure
occurs. Step up
to failure,
Legitimate Ye•
Ye•
Unit AddreS5 I
I~
Tie •elect into the
inactive state and
•cope the unit>
Inform
Programmer
Stop program just
before failure occurs.
Check for
program timing
problems.
Set ROS .top for unit address
fetch and start 1/0 routine.
At point of failure,
analyze CSW for
poss;hle clues
No
Examine CCW sequence (using
CSW info) for illegal commands
and slow functioning CCW's
Correct and
repair unit. Yes
Try other units o
foiling channel
Interface
sequencing
problem.
No
No
Use logout print option to
print channel lag data and
channel local store words.
If usable,
return system
to cus tamer.
Use printout and flowcharts
ta determine scoping points
for fur~her analysis,
Examine channel
indicoton and
1.ise error check
No
anal sis rlia rams.
No
Yes
B
Intermittent
Place channel in manual mode.
Key in program if necessary.
Single-cycle and use inter-
face register keys and de hold
conditions to reach predicted
point of failure for de scoping.
Yes
No
Repair
Repair
No
e customer's
program to
analyze the
roblem
Yes
Diagnose from
indicator lam
Yes
Key in program, if necessary.
Set check control switch to
IGNORE. Use ac scoping
techni ues and flowcharts •
No
Repair
g FIGURE 99. SELECTOR CHANNEL MAINTENANCE APPROACH
Run
Functional
Tests
Yes
1 .. tall EC's with
all prerequisites
ond run customer's
program
Check PCI
request ond
interrupt
mask circuits
Analyze data
in local stor-
age loco ti ors.
Note ond record
all symptons for
discussion of prob-
lem with thers.
~"!Vest help
Check voltage
levels in each
channel board.