IBM FlashSystem 900, Service Manual

Page: 268 / 546

3746-900 MAPs
014
– On the Test 1 connector on the DCDP,
check:
Pin 34 '3745PRES' line is at 0v.
Pin 33 '3745ON' line is at +5v.
Refer to YZ page 234 for
test 1 pin assignment.
Are all voltages correct as indicated ?
Yes No
015
Exchange the DCDP. Go to
“3746-900 Maintenance Using a FRU
list” on page 1-28.
016
Go to Step 036.
017
the 3746-900's power sequence is controlled
by a host connected to the 3746-900.
– Check for -24v between frame ground and the
back of the host connector that initiated the
command at RPO 01S Jx pins 1 and 5. See
Figure 2-4.
Figure 2-4. RPO Location 07R-A1
– Check the '-24 v unit source' on pin 1.
Is -24v present on pin 1 ?
Yes No
018
– Check that the cable is correctly plugged
into the J8 connector at the back of the
DCDP.
Is plugging correct?
Yes No
019
Plug the cable correctly and restart
the operation.
020
Exchange the DCDP. Go to “3746-900
Maintenance Using a FRU list” on
page 1-28.
021
– Check the 'Power hold command' on pin 5.
Is -24v present on pin 5 ?
Yes No
022
Host or cable problem.
023
– Check the 'SEQCOMPLEPO' on pin 35 of test 1
connector. Refer to YZ234 for test 1 pin assign-
ment.
(Step 023 continues)
2-10
3746-900: Service Guide