Test Mode - Sony ST-SB920 Service Manual

1. Circuit Check Mode
Set to the reception frequency that the curcuit can STEREO RDS stations. (Set the input level to above 70 dB.)
This enables circuit check to be performed in any of the reception modes-FM, AM (MW, LW). Set to a desired band before setting the test
mode.
1. Turn OFF the power.
2. While pressing 4 and AUTO-BETICAL SELECT together, turn ON U .
• The items in the following table will be checked automatically in order every 2 seconds.
Display Items
Tuned AST signal = LOW
IF Frq IF COUNT OK
Sig Level SI LEVELh 70dB
Stereo ST signal = LOW
RDS Signal RDS DATA OK
NOTE : The preset data will be erased when this test mode is used. Therefore, take down the data before setting this mode and preset the
data again after completing operations in this mode.
2. Display Tube Check and KEY Check mode
1. Turn OFF the power.
2. While pressing 1 and AUTO-BETICAL SELECT together, turn ON U .
3. While continuously pressing 1 and AUTO-BETICAL SELECT together, check the following.
Microcomputer version indication (1 sec)
Indication test pattern
1 7F 2 60
* The indication test pattern from 2 to 5 are indicated on only even grids.
The display changes every 1 sec.
4. Release 1 and AUTO-BETICAL SELECT . The KEY CHECK mode will be set.
5. All key numbers will be displayed.
Key Number : 27
6. Each time the key is pressed, the key number will be counted down.
Each key will be counted only once, at the first time.
7. When all keys have been pressed, the process will end.
SECTION 2

TEST MODE

DISPLAY
FM RDS
AM (MW, LW)
OK or NG
OK or NG OK or NG
OK or NG OK or NG
OK or NG
OK or NG
All light up "7F"
3 7E 4 3D
— 3 —
IC251 NG, RV251 adjustments
FE101, IC251 NG, or IF count buffer amp (Q251, Q401) NG
IC221 NG, RV221 adjustments
IC301 NG, RV301 adjustments
IC801 NG
Dot area only "60" Dot area only "7E"
Dot area only "5F" Dot area only "3D"
5 5F
NG