TM 32-5835-005-14 & P
TESTING AFTER REPLACEMENT OF REC/REP BOARD
cassette with blank tape into unit.
7-28. Test Equipment Required.
a. Audio Generator AN/URM-127.
Adjust oscillator output to 0dB.
b. VTVM Type ME318/U.
c. Set channel selector switch to
7.29. Testing Procedure for Audio
channel 1, AGC/MAN switch to MAN. Speed
selector switch to 15/16 IPS.
a. Connect audio generator to RCVR 1
input and adjust to 1 KHz at 0dB output
channel 1 gain control to +7dB.
b. Place both channels in AGC mode
and activate RECORD.
Decrease audio generator oscillator to
c. Connect VTVM to TP-1 and adjust
R-16 for 1.74 VRMS (+7dB).
f. Reset unit counter to 0; place unit
d. Reconnect generator to RCVR-2.
into the RECORD mode.
Reconnect VTVM to TP-2 and adjust
10 counts 1000Hz
R-35 for 1.74 VRMS (+7dB).
10 counts 4000HZ
10 counts 200HZ
f. Both channel meters should have
10 counts 400Hz
indicated center of red zone. If not,
10 counts 2000Hz
per Section VIII.
g. Rewind unit to 0 on counter. Set
g. Disconnect VTVM.
the 0dB range.
7-30. Testing Procedure for Equaliza-
h. Place unit into the REPRODUCE mode.
i. Adjust channel 1 gain control to
0dB at 1000Hz; at 4000Hz adjust R14 on
record/reproduce board (A1A3) to 0dB.
Bias board adjustments must be correct
j. Note and record readings for 200Hz,
made. Due to slight variations in the
400Hz and 2000Hz. All readings should
characteristics of the record/playback
be 3dB with reference to 1000Hz at 0dB.
head and other components, on rare
occasion, it may be necessary to ad-
just R16 and R17 on the bias board
RCVR 2 input.
of a volt to obtain proper equaliza-
l. Repeat steps a. through h. Insure
channel selector switch is in channel 2
1 input. Connect headphone output
m. Adjust channel 2 gain control for
with 600 ohm load to audio gener-
0dB. At 1000Hz, adjust R34 on record/
reproduce board (A1A3) for 0dB at 4000Hz.