Technics RS-M228X - Page 8

RS-M228X
MEASUREMENT AND ADJUSTMENT METHODS For dbx SYSTEM)
START
@ Check for
expansion
© Check the voltage at individual
sections of the regulated power supply
circuit in dbx circuit
e Adjustment of regulated power
supply circuit in dbx circuit
@ Repair the power supply circuit section
@ Check for ree ey
expansion
© Check for
standard level of dbx
@ Adjustment of dbx standard level
Repair the control circuit section control
@ Check for
expansion
check of INPUT BAND >>
ASS FILTER (27H2—20kH2)
_Ghack of RMS
FILTER (27H2—10kHz)
_ [ONPAGE13] |
@ Check for
expansion
@ Check the frequency
tesponse of the dbx circuit
TROUBLESHOOTING CHART FOR dbx SYSTEM
Fig. 1
Check the constants of the INPUT
BAND PASS FILTER elements
Check the operation of transistors |
203 and 0204 4
Check the constants of the BAND
PASS FILTER elements
Check the operation of transistors
0221 and 0222
¢ TROUBLESHOOTING CHART FOR dbx SYSTEM
The troubleshooting chart for the dbx system is shown in Fig. 1.
Please follow the sequence of this chart for checking and
repairing the dbx system.
The figures shown in each block indicate the page on which
the checking method, adjustment or measurement is explamed.
Repair the INPUT BAND PASS
Repair the RMS FILTER section
Check the voltages and signal wave
forms at individual sections of the
RMS detector
1
Repair the RMS detector section
Check the voltages at individual
sections of the VCA circuit. Check
the constants of the Pre-emphasis/
De-emphasis circuit elements.
Repair the VCA circuit section or
Pre-emphasis/De-emphasis circuit
Output signal distortion factor
adjustment