Sony WM-10 - Operation, Power, and Converter Issues; No Operation Troubleshooting; Noise when Battery is Worn Out

WM-10 WM-20
• No Operation
* Noise when battery is worn out {less than 0,9V)
• Mo Operation
Cause
Defective Location
Battery worn out
Battery terminal plate dirty.
Clean terminal plate (Daifron solvent)
Dirty leaf switch contact point.
S303-3 contact point cleaning (Daifron solvent)
flattery short: battery + terminal and audio board ground
touched.
Stick insulation on audio board.
Short of function plate ass’y mounting screw tip and
audio hoard pattern.
Stick insulation on audio board.
contact laaf
audio hoard
insulation
* Noise when battery is worn out
Operation: When{§}becomes 1.0V, 040! goes off, Q3G1 turns on, grounds lC3Q3(3)and reduces buzz noise.
— 3 —