[hrhoward]

Hello,
I am trying to power up a HiT-18S with a Siemens 840.
Turn main power on, fans get to whirring. Push the power on button, nothing.
Here is a picture of what is going on inside the cabinet.
Siemens is not my forte.

Any help would be appreciated.

Thanks,
Heath

[cnzrepair]

Grab the Siemens control manual and figure out what the alarm lights mean. Too many red lights (possibly alarms) in your photo.

[hrhoward]

Best I can tell...
MMC CPU - 0 - Driver not loaded
NCK CPU - 2 - DRAM error on NCK CPU, defective during memory test after Power On
PLC CPU - steady red led - PLC in stop mode

Suggestions?

Thanks

[cnzrepair]

It is highly unlikely that the failure is on all 3 modules. Parity errors in a lot of cases point to a faulty power supply. I don't see any accessible test points for the power supply (P/N 6FC5114 0AB01 0AA0) on the front panel. Check if the other cards provide a test point for the +5VDC supply, tolerance is +/- 5% with minimal AC ripple.

Swap with a known good power supply from a similar machine. If the power supply is confirmed to be faulty, a rebuild of the power supply is recommended given the age of the control.

Good luck!