IBM System/360 2050 User Manual

2. Plot the three points on the S9 driver
operating voltage determination graph.
3. Assure that one minute of error-free opera-
tion is possible at ±7% from the operating point.
4. After the run, set +6 VAR to the operating
point.
LS Strobe Driver Identification
There are 18 separate strobe drivers. If bits are
being dropped, consider the possibility of a missing
strobe. The strobe distribution, on ALD page LS721,
is arranged as follows:
Strobe bits 00 and O 1
Strobe bits 02 and 03
Strobe bits 04 and 05
Strobe bits 06 and 07
Strobe bits 08 and 09
Strobe bits 10 and 11
Strobe bits 12 and 15
Strobe bits 13 and 14
Strobe bits 16 and 19
Strobe bits 17 and 21
Strobe bits 18 and 22
Strobe bits 20 and Parity 8-15
Strobe bits 23 and Parity 16-23
Strobe bits 24 and Parity 0-7
Strobe bits 25 and 26
Strobe bits 27 and 28
Strobe bits 2 9 and 30
Strobe bits 31 and Parity 24-31
Note: These circuits are al' located on the card at 01A-D4M6.
ROS 201- -Cycle One Sector of Local Storage
1. System reset; set check control switch to
STOP.
2. Display sector to be cycled.
3. Set rate switch to SINGLE CYCLE.
4. Set data keys 22 and 31 on.
5. Set ROS REPEAT INSN down.
6. Press START.
7. Restore ROS RE PEAT INSN.
8. Set data to be stored into local storage in
data switches.
9. Set rate switch to PROCESS.
10. Press START.
The following should occur:
Data keys to L-register.
L-register to local storage.
Local storage to R-register.
R-register to adder for half-sum error check.
~ If error occurs, LSAR will have advanced
one address.
Array Temperature
If intermittent troubles are experienced on local
store, check the array temperature. It should be
104°F, ± 1°.
Local Storage Heater
At time of installation, scope cycle time. Record
cycle time and the temperature at entrance to gate
near local store on shmoo page S9. The approxi-
mate cycle time should be 6 seconds on, 20 seconds
off.
Checking Drivers and Terminating Diodes
See the section entitled "Checking MS Drivers and
Terminating Diodes" under "Main Storage (MS)
Service Checks."
READ ONLY STORAGE (ROS) SERVICE CHECKS
ROS Retry Adjustment
This procedure is based on voltage and timings being
within specified tolerances. Refer to ALD AAOOO
for timings. Check -3 volts at 01C-ElB2D06 to be
within± 4%. Required equipment is an ohmmeter
and a Tektronix 453 oscilloscope.
1. Remove the 5801515 card from 01C-E2IA;
disable ROS retry by grounding pin 01C-E3C4Dll.
2. With the ohmmeter, set up the following
resistances on the two pots on the 1515 card:
a. Measure between pins 1 and 2 (Figure 88)
on the top pot and rotate the pot counter-
clockwise until a minimum reading of
about 0 ohms is obtained.
b. Measure between pins 1 and 2 (Figure 88)
on the bottom pot and rotate the pot clock-
wise until a maximum reading of about
1000 ohms is obtained.
3. Re-insert 5801515 card in 01C-E2IA.
Lower Pot
Upper Pot
FIGURE 88. MODULE ~JOE OF 5801515 CARD
Service Checks, Adjustment and Removal Procedure (3/71) 95

IBM System/360 2050 Specifications

General

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