Technics SX-KN920

ABOUT THE SELF-DIAGNOSTIC FUNCTION
This model has some self-diagnostic capabilities. When set to the self-diagnostic mode, operation of various components can be
verified by following the procedures in the chart below.
[No | PCB TEST MODE
MAIN RAM (iC21), ROM (IC15, 1.Connect the CHECKING DEVICE (refer to page 1-12) to CN12 on the
IC17-20) check MAIN P.C.B. , and turn on the CHECKING DEVICE switch.
2.Turn on the power switch.
When the power switch is turned on, the LED of the CHECKING DEVICE flashes 8 times. The first 4 flashes
are for the RAM check, and the latter 4 flashes are for the ROM check. The order of the LED flashes
correspond to the respective IC numbers as shown below. If an IC is defective, the corresponding flash time
is longer.
RAM ROM
Examples aT La
1 2 3 4 3 4
1. RAM OK, ROM OK ———————- ® @®e @®@ -
I
I
2. RAM OK, ROM(IC17) defective | -————————> @ e e e .-
!
1
3, RAM(IC21) defective, ROM OK —__——__+ = ee e oo -
NOTE: @ indicates short flash time IC21 1C18 IC17
m= indicates long flash time - ICi9
e---o--@-
—@--4f---onr
-—_
IC20
Control panel CPU check 1.Connect the CHECKING DEVICE to CN 12 on the MAIN P.C.B.
(The Checking Device switch should be off.)
2.Press and hold the two D keys shown below, and then turn on the
power switch.
ee
D keys
When the power switch is turned on, the LED of the CHECKING DEVICE flashes 4 times. The order of the
LED flashes corresponds to the CPU(IC) on the respective P.C.B..s as shown below. If an IC is defective,
the corresponding flash time is longer.
2 3 4
1.
OK
rs
—-_——
2.
CPU
defective
——
rs
NOTE: @ indicates short flash time
m= indicates long flash time
Ma,
wy
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