No Key Response (Micro Board Failure); User Data Store Failure (Micro Board Failure) - Tatung OMNISCAN SERIES Service Manual

6.27 NO KEY RESPONSE (MICRO BOARD FAILURE)
ERROR/NO RESPONSE
ON KEY PRESS
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YES
NO RESPONSE - - - - - -
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ONLY ONE KEY NO 1
RESPONSE
-------------------------->1
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1
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1
NG
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r---------------->
CHECK KEY SW. KEY MATRIX
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I C K T . SHORT
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OK
P503
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NG
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CHECK PWM OUTPUT
---------1
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CHANGE KEY
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SW.
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OK PWM CKT.
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PWM OUTPUT
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1 LOWPASS FILTER I
1
CKT. FAILURE
1
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L--------------------> I <-----------------!
----J
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END
6.28 USER DATA STORE FAILURE (MICRO BOARD FAILURE)
USER DATA
STORE FAILURE
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OK
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r----------------->
CHECK MEMORY
-------------->
0513, PINS 1, 2, 3, 4, 7
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OK
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PCB TRACK CHECK
SHORT 0512
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L-____________________ >I
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END·