IBM System/360 2050 User Manual

8. If the card was not at fault, turn CPU roller
2 to position 7 and check that the current ROS ad-
dress is 000.
l). Place the FLT control switch in repeat.
10. Set the ROS address compare switch to stop.
11. Place F49 in data keys 20-31 (checks scan-
in, QY110).
12. Turn CPU roller 1 or 2 (depending on the
trigger being tested) to the position containing the
failing trigger.
13. Press start.
14. If the block indicators light is on, use the
force indicator switch to check the value. The trig-
ger should be in the state that is being tested for.
If not, refer to the logic and the scan-in paths. The
logic involves a maximum of four cards on scan-in.
15. If scan-in is correct, place F4F in data keys
20-31 (QY510).
16. Press start. SDR contains the actual re-
sponse. To find the tested bit, refer to Figure 36
and the logic.
1 7. For one-cycle tests, the segment number
and test number are displayed in SDR (16-31). Find
this number in the appropriate Scopex volume.
18. Rotate CPU roller 2 to position 7 (current
ROS address) for one-cycle tests, or position 8
(previous ROS address) for two-cycle tests (segments
four and six).
19. Place the value of the current ROS address
for one-cycle tests, or the value of the previous
ROS address for two-cycle tests (segments 4 and 6)
in data keys (20-31). This is the stop address for
static scoping. (Emulators use data keys 19-31.)
2 0. Place the FLT control switch in the repeat
position.
21. Press start. The output point (first line) of
the failing test may be scoped dynamically. All
other points may be scoped either dynamically or
statically.
22. To scope the output of the failing test dynam-
ically:
a. Attach the sync lead to the sync box (positive
sync).
b. Rotate the switch on the sync box to FLT
cycle sync. If sync box is not available, sync
minus on B-D1C3D10 (KH331).
c. Set the scope time base to O. 1 microseconds/
centimeter. (This displays two cycles.)
d. For two-cycle tests sync on first sync pulse.
23. The area of the scope face to check depends
on the circuitry being scoped.
a. For group A, look during and after output
trigger clock time (the group is indicated in
Scopex next to test number. See Figure 9).
b. For group B, look during clock time.
c. For group C, look before and during clock
time.
d. For group D, look before clock time.
Figure 34 is a simplified description of the fol-
lowing steps (24-29):
24. Place the scope probe on the output point. If
the output level agrees with Scopex and holds that
value until logged (see logout chart), check the test
number and segment number (step 17) with FLT con-
trol switch in process. If step 1 7 is correct, check
the logout circuitry. If the output level agrees with
Scopex and does not hold its value until logged (a
clock pulse is gated to the trigger before it is logged,
or an input has changed during scan-out) or if it does
not agree with Scopex, go to step 25 (static) or to
step 26 (dynamic).
25. Statically scope as follows:
a. Set the ROS address compare switch to stop.
Machine will stop unless the wrong ROS ad-
dress is set up. (See step 18.)
b. If the check register gated indicator is on,
go to step 26; otherwise, continue pressing
start until the indicator comes on.
26. Scope the G/F entries. If the G/F entries
do not agree with Scopex, continue; otherwise, go
to step 29.
'2.7. Check to see if the output point is listed as
an entry.
a. If the output point is also an entry and this is
the error register (KTOll-031), ignore this
entry and scope other G/F entries. If the
output point is also an entry and this is logic
(KSlOl-171, KS201-231, or RPOll-021),
these triggers have latch-back paths. Refer
to logic and repair or bypass the test(s)
(step 28) till the output point is not an entry.
b. If the output point is not an entry, bypass
the test(s) (step 28) until this net (G/F entry,
step 26) is not listed as an entry. If there
are no similar failures, return to the orig-
inal stop, refer to the logic and repair (scan-
in, dead entry, or ROSDR failure).
28. To bypass tests, place the FLT mode switch
in the force pass position, press start, return the
FLT mode switch to the load position, and press
start again.
29. Scope the G/F points in order after the output
point.
a. If there are no G/F points, change the cards
listed at the end of the test.
b. If a G/F point agrees with the Scopex:
1. Go to the previous bad G/F point and
scope its inputs (FED BY).
2. If the inputs agree with Scopex, the card
or some other point in the failing net is
bad.
Maintenance Features (3/71) 59

IBM System/360 2050 Specifications

General

Brand	IBM
Model	System/360 2050
Category	Computer Hardware
Language	English