1. CIRCUIT CHECK PROCEDURE
1) Low Voltage Transformer (DMR-604P) Check.
The low voltage transformer is located on the P.C.B.
Measuring condition: Input voltage: 120V
Frequency: 60Hz
2) Voltage Check
Key check point
CHECK METHOD
43
PRINTED CIRCUIT BOARD
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 norminal voltage.
NOTE : Each measure point must be measured with GND points.
1
2
10
8
7
6
NO.
MEASURE POINT
WAVE FORM
REMEDY
REMARK
1
MP1
DC –5V ± 0.25
Replace ZD2, EC1, EC2
NO LOAD
2
MP2
DC –30V ± 1.0
Replace R21, ZD3
NO LOAD
3
MP3
DC –27V ± 1.0
Replace R21, R22, EC5
NO LOAD
T
0V
-14V
T: 16.67 ms (60 Hz)
T
0V
-5V
T: 250ns
NO.
CHECK POINT
REMARK
1
IC1 PIN 6, 10, 11
–5VDC
2
IC1 PIN 1
–30VDC
3
IC1 PIN 22
4
IC1 PIN 8 or 9
5
DP1 PIN 1 & 25
2.4 VAC (DISPLAY FILAMENT VOLTAGE)
Voltage
Terminal
LOAD
NO LOAD
6–7
24V
30V
8–10
2.4V
2.5V
Содержание MFM-6D
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Страница 50: ...2 P C B CIRCUIT DIAGRAM MFM 7DTP 49 ...
Страница 52: ...51 4 PRINTED CIRCUIT BOARD ...
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