Lorain Power Equipment....battery charger schematic needed

[Y2KEDDIE]

I have acquired a H100F25, 100A 24V charger. The unit works, but I'd like to get a schematic as it has several circuit boards and if it ever fails I'd like to be able to repair. This unit is 45 years old and Lorain has changed hands many times. Hopefully some one is familiar with this charger.