KV-S8147, KV-S8127, KV-S8150, KV-S8130, KV-S8120 - Panasonic Other Service Manuals Service Manual (repair manual). Page 108

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5. Double Feed Detector (G) does
    not work, properly.

1. Execute “Double feed” in Sec. 10.3.8. to 

adjust “Send Level” for Double Feed 
Detectors.

2. Execute “Double feed” test in the Sec. 

10.3.7. to check the detector condition.

3. Check the following aligned property of the 

Double feed Detection sensor. 
a. SN3750,SN3751,SN3752 (USS(R)/WAIT 
    SENSOR Board)
b. SN5210,SN5211 (USS(L) Board) 

4. Check the following connection and 

soldering condition on each connector.
a. CN3750 (USS(R)/WAIT SENSOR Board) 
    to CN3005 (UPPER RELAY Board)
b. CN5210 (USS(L) Board) to CN3006 
    (UPPER RELAY Board)
c. CN3004 (UPPER RELAY Board) to CN19 
    (CONTROL Board)

5. Check the following parts' soldering condition 

to repair it.
a. UPPER RELAY Board 
    IC3005-6,7,8,9, and 12th pins)
b. UPPER RELAY Board
    Q3006 to Q3050 and surrounding circuit.

6. Check the following signal of UPPER RELAY 

Board.
a. CN3004-1 and 2nd pin: 24 V
b. CN3004-9,11,12,13, 14th pin (JS_CLK) :  
    300 kHz
c. CN3006-1, 3rd pin (USS+), 
    CN3006-2, 4th pin (USS-), 
    CN3005-1, 3, 5th pin (USS+), 
    CN3005-2, 4, 6th pin (USS-) :
                         Approx. 300 kHz Sine wave 

7. Replace faulty parts or boards.

6. Double Feed Detector (R) does
    not work, properly.

1. Execute Double feed test in Sec.10.3.7. to 

check the detector condition.

2. Check the aligned property of the Double 

feed Detection sensor.

3. Check the following connection and 

soldering condition on each connector.
a. CN3900 (SKEW DETECT SENSOR(R) 
    Board) to CN3303 (LOWER RELAY 
    Board)
b. CN3800 (SKEW DETECT SENSOR(R) 
    Board) to CN3302 (LOWER RELAY 
    Board)
c. CN3304 (LOWER RELAY Board) to CN18    
    (CONTROL Board)

4. Check the following parts' soldering condition 

to repair it.
All mounting parts of LOWER RELAY Board

5. Check the following signal of LOWER 

RELAY Board.
a. CN3304-1 and 2nd pin: 12 V
b. CN3304-4th pin: 5 V

6. Replace faulty parts or boards. 

U25 (Detect document 
with staples (Double-
feed detection))

1E

00

00

00 1. Refer to each item of Error Code U23.

U26 (Bent Paper was 
detected.)

1F

xx

00

00 1. Bent Paper was detected.

1. Check whether the scanned documents are 

stapled

2. Set the documents neatly on the Feed Tray, 

and then scan them again.