Service manual

STP 11-25R13-SM-TG
3 - 6
Performance Steps
11. Inspect lubrication of components (capstan, motor, lever, gear shaft, threading ring, or cam
assemblies).
a. Disassemble and clean out the old lubricant before adding fresh oil or grease.
b. Apply a light machine oil on gear and wheel shafts, as well as bearings and pivots.
c. Apply a plastic, safe grease-like silicone lubricant to gears, cams, mechanical-type mode
selectors, sliding parts, and gear teeth.
d. Reconnect the AC plug and turn ON the VTR.
12. Check mechanical alignment.
a. Insert a work tape in the VTR; load, eject, thread, and unthread repeatedly until observing an
even distribution of lubricant.
b. Listen for abnormal mechanical noises; for example, grinding gears.
c. PLAY, FFWD, REW, PAUSE, and STOP the work tape in the VTR to verify that the tape path is
in proper mechanical alignment; that is the tape does not wrinkle, crease, fold, break, or bind.
13. For difficulty in switching between JOG and SHUTTLE, lubricate the SEARCH DIAL assembly.
a. Remove the SEARCH DIAL assembly from the function control chassis block.
b. Set the SEARCH DIAL to the SHUTTLE mode (lock-in guide forward and shaft protruding).
c. Apply one drop of light oil.
d. Alternate between JOG and SHUTTLE several times to verify smooth action.
e. Reinstall the SEARCH DIAL assembly onto the function control chassis block.
14. Turn OFF power and spot clean the tape path with a chamois dampened with isopropyl alcohol to
remove any debris or lubricant displaced while using the work tape.
15. Replace all shielding, hardware, and anything else removed or displaced in performance measure 4.
Reapply power to continue.
16. Operations check the VTR.
a. Check the PLAYBACK mode.
NOTE: Video performance verification starts with the playback heads.
(1) Connect the VTR outputs to a WFM, vectorscope, and color TV receiver (or color monitor,
audio amplifier, and speakers).
(2) Insert and PLAY an alignment tape with 1 kHz audio tone at 0 VU and color bars, 1 V
peak-to-peak (P-P) at 140 IRE.
(3) Verify the VTR outputs using the monitoring equipment.
NOTE: When playing the alignment tape, low off-tape RF level with peaked tracking indicates worn video
heads in need of replacement. Tearing or bearding during video playback with sharp, dark-to-white
transitions also indicates a worn head.
b. Check the E-E mode.
(1) Connect audio video signal generator(s) to the VTR audio and video inputs.
(2) Turn ON power to the signal generator(s) and select 1 kHz audio tone and color bars, 1 V
P-P at 140 IRE.
(3) Verify the signal generator outputs through the VTR using the monitoring equipment.
c. Check the RECORD mode.
(1) Insert a work tape and RECORD for 1 to 2 minutes.
(2) PLAY the recorded tape on a known good VTR to verify interoperability.
d. Check front panel and remote control settings and functions for proper operation.
17. Complete the necessary maintenance forms.
a. Annotate service performed and hours meter reading from the VTR for time change item (TCI)
replacement requirements and periodic checks and maintenance on DD Form 314.
b. Document uncorrected faults and parts required on DA Form 2404. If no fault exists, date and
initial the form.
c. Initiate a DA Form 2407 for malfunctions not corrected during the PMCS.