Service manual

STP 11-25R13-SM-TG
3 - 8
PERFORM PMCS ON A DIGITAL AUDIO TAPE (DAT) MACHINE
113-575-3051
Conditions: In a tactical or garrison environment, given a DAT machine, audio amplifier, speakers,
ATSG, associated cables, prerecorded and blank DAT tapes, chamois, foam-tipped swabs, pure
isopropyl alcohol, felt-tip pen, manufacturers' manuals, DD Form 314, DA Form 2404, DA Form 2407,
and DA Pam 738-750.
Standards: The standards are met when the DAT machine plays and records without error after cleaning
and demagnetizing the tape transport controls.
Performance Measures Results
1. Recognize indications that the heads or tape path require cleaning. Indications include
audible errors or glitches (noise bursts or dropouts) and display errors reading too high
(over 100).
P F
NOTE: Dust, oxide, or tape misalignment can cause errors. A glitch occurs when the error-
correction circuit cannot remove all the errors.
2. Eject and remove the DAT from the machine. P F
CAUTION: Never leave a DAT (or any other kind of recording tape) in a machine when
turning OFF power; this is bad for the tape and jams transports. Also dry cleaning tapes are
abrasive; that is, harsh on the heads.
3. Turn OFF DAT machine power. P F
4. Open up the machine for access to clean the tape path. P F
5. Clean the tape path by hand with chamois cloth and swabs dampened with pure
isopropyl (or ethyl) alcohol.
P F
a. Swab stationary guides, rollers, capstan, and pinch roller. P F
b. If necessary, power ON and OFF a couple of times to rotate the capstan for
exposure and access to clean the entire capstan.
P F
NOTE: Deposits and grime on the capstan correlate to mistracking; that is, the analog
output sounds like a chainsaw for seconds at a time.
c. To clean the heads and drum, hold a chamois cloth wrapped around your fingers
lightly against the side of the drum and simultaneously turn the drum in one
direction.
P F
CAUTION: To avoid breaking the heads, do not apply vertical (up or down) pressure to the
heads.
d. Dry quickly to avoid leaving residue behind. P F
NOTE: Label DATs with felt-tip pens only; ballpoint pen ink and pencil graphite leave solid
residues that can fall into transports.
6. Inspect threading transports. P F
a. Lubricate dry components (capstan, motor, lever, gear shaft, threading ring, or
cam assemblies).
P F
b. Disassemble and clean out the old lubricant before applying fresh oil or grease. P F
c. Apply a light machine oil on gear and wheel shafts, as well as bearings and pivots. P F
d. Apply a plastic, safe grease-like silicone lubricant to gears, cams, mechanical-type
mode selectors, sliding parts, and gear teeth.
P F
7. Demagnetize the tape transport controls. P F
8. Put the cover back on, check that all cables are connected, and then reapply power. P F
9. Operations check to ensure no problems exist. P F
a. PLAY a prerecorded DAT and monitor the audio level and quality. P F