Sony RMT-B101A - Key 0 Inactivity Issues (Flowchart 1)

5-14
Flowchart No.1
FL Section
Key 0 is inactive Key 1 is inactive Flowchart.
Is about 5V present in CN100 28pin without pressing a key?
Check 5V line, R124 periphery and conductors on the FL board.
If faulty, replace the FL board.
Yes
Yes
Does the potential of CN100 28pin (Key 0) change to
around 1.4V when CN102 4pin and 5pin are short-circuited?
No
Check resistance of resistors on Key1 line.
Also, check peripheral conductor patterns and FFC.
If faulty, replace the FR board.
Yes
No
No
Key 0 is inactive Flowchart.
Key 0 line is broken.
No
Yes
Does the potential of CN100 28pin (Key 0) change
to around 4.3V when Power button is pressed?
No
Check the resistors and conductors on Key 0 line.
Key 1 is inactive
Is about 5V present in CN100 8pin without pressing a key? Check 5V line, R120 periphery and conductors on the FL board.
If faulty, replace the FL board.
Yes
Yes
Does the potential of CN100 8pin (Key 1) change
when CN101 4pin and 6pin are short-circuited?
No
Check the resistors and conductors on Key 1 line.
If faulty, replace the FL board.
Check resistance of resistors on Key1 line.
Also, check peripheral conductor patterns and FFC.
If faulty, replace the FR board.
Yes
No