IBM Magstar MP 3570 C Series, Maintenance Information

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Some of the signals between the drive logic card and the drive analog card are transmitted through the flat
ribbon cable, item
14
.
Drive Logic Card to Drive Servo Card Interface:
The drive logic card is also the primary
electronic source for controlling movement of the reel-to-reel motors, the head actuator, and readout of the
loader sensors. The drive logic card provides control registers for each of these functions, which in turn
are powered by the drive servo card to perform the actual movement of motors and solenoids. Feedback
of tach pulses and sensors is transferred to the drive logic card from the drive servo card for processing
by the microcode.
Reset and Power Controls:
Power-on reset for the 3570 is handled by the drive logic card. It
checks power as it is switched ON or OFF, and provides reset levels to the other electronic circuits until
power is at the proper levels. This
clamping of the electronic cards keeps noise and glitches from
occurring during power transitions.
Drive Analog Card
The drive analog card, item
4
, contains the write drivers, read pre-amplifiers and bias circuits for both
data and servo channels. It provides precise switching of write current for four channels at a time to the
R/W head during a write cycle, and detects and converts analog signals from the R/W head to digital
signals during a tape read cycle. The drive analog card is designed and positioned so that it makes
physical contact with the R/W head through thin film cable connections, item
5
, yet can still be plugged
into the mother board. The R/W head is part of the head-actuator assembly, item
1
.
Head-Actuator Assembly
| The head-actuator assembly, item
1
, contains the R/W head, and the actuator assembly, factory
| pinned. The entire unit is a single assembly. The R/W head transfers write current as controlled by the
drive analog card to the tape as it passes in contact with the R/W head during a write cycle, and transfers
signals from the tape as it passes in contact with the R/W head during read cycles. The actuator
assembly positions the head in the appropriate location to read or write across the width of the tape.
Drive Servo Card
The drive servo card, item
8
provides circuitry that drives the loader motor, reel motors, and head
actuator from signals originating in the drive logic card. It is the last card in the stack to plug into the
mother board.
Loader Assembly
The loader assembly, item
12
, is mounted on the bottom plate, item
9
. The loader assembly contains
the mechanical and electrical components to move the tape cartridge into and out of the loader, to move
the tape forward and backwards, to sense when the tape cartridge is in position to be read, and to sense
| the type of tape cartridge that is loaded. The loader assembly as attached to the bottom plate is a single
| assembly.
Drive Sensor Cable
The drive sensor cable (not shown) is connected to numerous sensors and components on the loader
assembly, and is replaceable without replacing the loader assembly. It attaches at the other end to the
drive servo card.
INTRO-20
IBM 3570 MI