Cause of issue:
1. Is +5V power or GND supplied?
2. Is +5V and GND short-circuited?
3. Is the OE signal of the fifth leg of 138 available?
4. Whether the OE signal connected to 245 is normal (open circuit or short circuit);
Failure analysis and processing:
• Supply +5V or GND
• Disconnect the short circuit
• Supply the OE signal to
• Connect the open circuits and disconnect the short circuits.