Daewoo KOG-875T2S, Руководство по обслуживанию

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PRINTED WIRING BOARD
1.CIRCUIT CHECK PROCEDURE
1) Low voltage transformer (DMR-984FS) check.
The low voltage transformer is located on the P.C.B.
Measuring condition:
Input voltage: 230VAC/50Hz
2) Voltage Check
• Key check point (1~5: Micom Pin, 6:Display Pin)
• CHECK METHOD
Terminal
1-3
6-7
7-8
9-10
Voltage
230.0V
9 VAC
9 VAC
2.3 VAC
1
9
8
7
6
10
3
5
NOTE 1 : Secondary side voltage of the low voltage transformer changes in proportion to fluctuation of power
source voltage.
NOTE 2 : The allowable tolerance of the secondary voltage is within ± 5% of nominal voltage.
NO. CHECK POINT REMARK
1 PIN 63, 64 +5VDC±5%
2 PIN 29, 32, 62 0V
3 PIN 28 +5VDC±5%
4 PIN 45
5 PIN 30, 31
6 PIN 1, 25 2.6VAC (Display filament voltage)
NO. CHECK POINT REMARK
1 +5VDC Replace Q3, ZD3, R26, C10
2 +12 VDC Replace D7, D8, EC2, EC3, C14, C11
3 -24 VDC Replace D9, D10, EC4, EC5, C15
NOTE :
The marks of the above corresponding voltages (+5, +12, -24VDC)are written on the PCB.
Each measuring points must be measured with GND points.
0V
+5VDC
T
0V
5V
T
T=0.25us (4.0MHz)
T: 20 ms (50 Hz)