
NO
YES
B
Response change properly?
Check U112,±17V at tone board
Check TONE_STB,OPSEL_DATA
OPSEL_CLK signal
THE END
Press Tone Key to change
tone setting,measure preout
response
YES
Level=2V±0.1V
THD<0.03%?
NO
Check U109 U209 U111 U211
Check OPSEL_STB signal
Press Z-2/record key to current
input channel then measure
output level and THD
3-5