IBM 5280 Maintenance Information Manual page 92

LED: (See 371
D).
Light emitting diode. An electronic
part used as a source of light.
LEDCP: (See 33311). Light emitting diode connector
pin.
MFM: Modified frequency modulation. (See modulation.)
MIM: Maintenance information manual.
mm: Millimeter.
modulation: The process of varying the amplitude or
frequency of the read/write signals.
ms: Millisecond.
ms/cm: Milliseconds per centimeter.
mV: Millivolt.
NC: Normally closed.
NO: Normally open.
ns: Nanosecond.
phototransistor: (See 375
m).
An electronic part used
to sense the light of an LED.
80 Glossary
PTX: See phototransistor.
PTXCP: (See 333
0).
Phototransistor connector pin.
rpm: Revolutions per minute.
SCP: (See 333
II).
Solenoid connector pin.
SMCP: (See 333
II).
Stepper motor connector pin.
solenoid: (See 330
II).
An electromechanical part that
operates the bail assembly to load and unload the
read/write heads.
TP: Test point.
V: Volts.
Vac: Volts, alternating current.
Vdc: Volts, direct current.
VFO: Variable frequency oscillator. An electronic circuit
used to synchronize the read and write circuits with
diskette rotation in FM and MFM recording.
V/cm: Volts per centimeter.