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1.1 DIAGNOSTIC TECHNIQUES
WARNING: Voltage is present on both sides of most
circuit cards. Metal caps of transistors are often a
part of the circuit. Avoid pulling or replacing cards
with the d-c power on, since a resultant short circuit
could damage transistors or other components in the
circuit.
WARNING: A potential of +48 volts is present for
head pick, cartridge lock, access amplifier, and
.voltage regulator circuits. A potential of +36 volts
is present for write circuits. Exercise care when
probing near SLT cards containing these circuits to
avoid possible shorts which could result in extensive
damage.
Intermittent problems can sometimes be aggravated
by vibration. Tapping the edge of cards with the
plastic handle of a screwdriver in the area suspected
should be sufficient. Use caution because excessive
vibrations can cause a short circuit in adjacent card
components.
Conditions will arise where it is desirable to
jumper in signals or voltages to specific inputs or
outputs to check certain functions. Care should be
taken to ensure that logic blocks are not overloaded
during these checks, as erroneous indications will
result. More important, avoid the use of high volt-
ages which can damage or destroy the transistors.
For the majority of logic block cases, a properly
placed ground will create the effect desired. All
other cases must be treated individually based on
knowledge of the circuits involved.
Special circuit card diagrams are shown in the
system diagrams. Also shown are input and output
waveforms for most of these cards.
When the electronic gate is opened to check the
positioning of SLT cards, care should be taken to
properly replace the SLT card support before closing
the gate. This support serves to rigidly brace the
outer edges of the cards with the gate housing to
minimize card vibration. The support normally
interferes with the bottom of the electronic gate to
provide a preload on ends of the SL T cards.
227-5984 (9/65)
CHAPTER 1 DIAGNOSTIC AIDS
1. 2 FUNCTIONAL CHECK
The functional check provides for operating the equip-
ment without using signal control circuits of the
Central Processing Unit (CPU). This check verifies
that the drive actuator, carriage access motion,
head selection, and start/stop equipment functions
will perform as required.
The CE control panel contains switches which be-
come active only when the CE Interlock signal cable
between system control and the IBM 2310 is discon-
nected. Upon disconnecting this cable from system
control circuits, the disk storage drive is automa-
tically placed in a read select mode to prevent inad-
vertent erasure of recorded data, and to allow the
CE to examine the read circuit and recorded data.
The functional check is to be accomplished as follows:
NOTE: No CE check is provided on the 2310 for
writing information.
1.
Remove CE Interlock signal cable.
2.
Ensure ac and dc power is available to machine.
3.
Install CE cartridge.
4.
Energize drive motor.
5.
Using CE SWitches, access carriage and select
each head to determine that machine operates
satisfactorily.
1.3 READ MALFUNCTIONS
1. 3. 1 Read Circuit Troubleshooting (Figure 1-1)
All read/write safety circuits in the machine
are coupled with the write lock latch, which becomes
set and produces a write select error signal when
incompatibility exists at gated outputs from read/
write lines. Always check the write driver SL T
card when neither read nor write operations function.
When the Write-Lock latch becomes set, File
Ready condition is removed from the machine,
and the carriage will access to home position
(track 000) and stop while the disk will continue
to rotate.
1. 1
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Table of Contents
Troubleshooting
