S5 110

[Guest Goody]

Hy chaps need someone with Siemens experience here Today I was called to an old S5 110 ZB/CPU It is a rack mounted system with 4 input modules and 2 output modules. I was informed the machine had been powered off for about 2 weeks and when they turned it on the fault red light was on - on the cpu unit. While it was powered up I turned to run switch to OFF then back to CYCLE and the red light went out. Everything seemed ok for a while then the output modules led’s started chattering causing valves and relays to chatter too. I checked all the voltages to the outputs modules and the 24V dc in to these was stable but the outputs were jumping around. I then took out each module and cleaned the backpane contacts. Things once again settled down for a while although I never got the machine to run properly. The problem as it stands is - each time the power is cycled, the red led comes on but goes off when the run switch is cycled. Oh and the battery was last replaced in 1992. Do you think the program is corrupted or maybe the cpu or eeprom is faulty.