Tascam 388 Studio 8 - Service Chart -28

1-5-13. ServiceChart
AD-
JUST
STEP
WHAT IS IT
CALLEO
SIGNALSOU RCE
ANO AMOUNT
WHAT TEST
GEAR TO USE
WHAT IS THE RE-
CGRDER DGING?
PGINT TG
ADJUST
WHAT READING TG
ADJUST FGR
1 Reproduce Head
Aíignment
TEAC YTT-1003
Playback Aíign
ment Test Tape
VTVM and Oscil-
loscope with verti
cal and horizontal
inputs connected
to TAPE GUT
tracks 2 and 7.
Reproduce mode. Repro head
azimuth adjust-
ing screw.
Adjust for máximum
output and for output
of tracks 2 and 7 less
than 90° out of phase.
(at 10 kHz)
2* Reproduce Level
400 Hz signal on
TEAC YTT-1003
playback Aíign
ment Test Tape
VTVM connected
to TAPE GUT
jack
Same as above Trim pot
R128/R228
-12.6 dB (0.23 V) on
VTVM
2*
REPRO EQ
16 kHz signal on
the tape.
Same as above Same as above Trim pot
R124/R224
Same as above
4*
LINE INPUT
Level
400 Hz signal at
-10 dB from oscili-
lator connected
to LINE IN jack
Same as above Record mode.
Input Fader Adjust to read 0 VU
on VU meters or
-lOdBat PGM
GUT.
5*
Blas Trap Ad-
justment
No input signal VTVM connected
to Bias Trap test
point TP-1, nega-
tive lead to
ground, positiva
lead to test point.
Record mode, no
input signal
Inductor
L104
Adjust Inductor for
minimum output at Bias
Trap test point TP-1.
6* Blas Level Ad-
justment.
Same as above
VTVM connected
between TP2 &
TP G.
Same as above
Trim capacitor
C103/C203/
C303/C403
While recording adjust
trim pot until VTVM
indicates 120 mV.
1*
Record Level
400 Hz signal at
-10 dB (0 VU on
VU meters) con
nected to LINE
IN jack
VTVM connected
to TAPE GUT
jack or use VU
meters
Record mode.
Trim pot
R143/R243
Set fo -10 dB (0.3 V)
at TAPE GUT jacks or
0 VU on VU meters
S*
Record/Re
produce Fre-
quency Res-
ponce.
30 Hz to 16 kHz
signal at -20 dB
connected to
Input termináis
Same as above
Same as above
Inductor
L103
Same as above
9*
Overall Signal-
to-Noise Ratio
No input signal
VTVM connected
to TAPE GUT jack
Same as above
Check for 50 dB or
better
REPEAT STEP MARKED WITH AN ASTERISK FOR EACH CHANNEL. THE ADJUSTMENT NUMBERS ARE THE SAME BUT
THE CIRCUIT BOARD LOCATION. INPUT/OUTPUT TERMINAL NUMBERS. VU METERS, ETC., WILL BE DÍFFERENT
DEPENDING ON THE CHANNEL.
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