Technics SX-KN1400 - Page 20

| No. | Diagnostic Part/Diagnostic Device Procedure of Service Mode
MAIN P.C.B.: Turn on the power switch while holding down the two E keys shown
Wave
ROM
(IC104-105)
check
below.
HH
;
When set to the self-diagnostic mode, the The key number indicates the Wave ROM number.
Wave ROM output a sine wave. The Wave (®: 1C104/105)
ROMs correspond to the keyboard keys as
shown in the diagram to the right. When a key
is pressed, the corresponding sine wave | |
sound is produced. If no sound is produced, or
if the sound is distored, the Wave ROM corre-
sponding to the key is defective.
* A more detailed explanation as to setting con-
ditions and other matters will be displayed on
the LCD for your reference.
MAIN P.C.B.: Peripehral devices Turn on the power switch while holding down the two A keys shown
1. FDC IC (IC 15) test below.
AH
(Reel
2. DSP IC (IC 109) test
1. The test results on the FDC IC will be displayed on the LCD. —
NOTE: This test only checks communications between the FDC IC and MAIN CPU. It does not test operation of the
FDC IC itself, the route from the FDC IC to Floppy Disk Drive operation.
To include the Floppy Disk Drive in testing, use the “Floppy Disk Drive SAVE/LOAD test’ described below.
2. The correct sine wave sound will be produced if the DSP IC is working properly.
NOTE: Set the MAIN VOLUME ito an appropriate level.
This test only checks the operation of the DSP IC itself. If the DSP IC operation is defective, check the relative
DRAM (IC 7108) also.
Floppy Disk Drive: 1.Insert the floppy disk formatted into the Disk Drive.
SAVE/LOAD test 2.Turn on the power switch while holding down the two B keys shown
below. =
WAU
Pressing the button below the “ p> ” displayed on the LCD starts the Floppy Disk Drive SAVE/LOAD test. The test is
carried out repeatedly.
Data is saved and loaded, and then the two data sets are compared. The number of times the test results “OK” or “NG”
are counted and displayed on the LCD. To stop the test, press the button below the “i” displayed on the LCD.
Even when the Floppy Disk Drive is functioning properly, the test can result “NG”. If this happens frequently, clean the
magnetic heads of the Floppy Disk Drive with a cleaning disk. Then, change the disk used in testing with another disk and
reperform the test. If the trouble is not solved, it is likely that the Disk Drive unit or some other part of the hardware is
broken.