Hello
I'm repairing a laser controller in my laboratory.
but the laser controller is over 20 years old and is not supported by the manufacturer...
so I disassemble and repair it myself, looking at the circuit board.
Currently, I'm having problem with the charging circuit part of the lead-acid battery.
However, I'm new to some battery circuits and confusing which part is broken or how to fix.
In this charging board, UN3906N is used for floating charging 12V battery.
so I'm here to get help from Texas Instruments technicians and users.
The current situation is as follow:
- The battery voltage is 13.7V, but become 0V instantly when power off. The battery, PS-1212 from Powersonic, is very old stuff.
- IC output pins, STATE LEVEL CONTROL and /Over Charge Indicate, are high from start.
- Driver never turn on from start. so charging current is not flowing.
- The above situations remain the same even after waiting over 10 hours.
The circuit schematic is attached file.
Please tell me how to fix or which part is broken.
Thanks for your help
and I'm sorry for my terrible English.
