No power to Paradigm Architectural Control Processor (P-ACP) in an ERn
Issue
The screen is blank with no backlight and visible text on the LCD on the Paradigm Architectural Control Processor (P-ACP), and no LEDs to the left of the screen are lit.
Explanation of Issue
This means the P-ACP in your ERn is not powered. If the rack was working previously, the first question to consider is if there was a recent power event. Power events can negatively affect different parts of the rack.
An ERn2 houses one P-ACP, while an ERn4 may house up to two P-ACPs. In a rack-mount ERn the P-ACP receives power from the Power Supply module (ERn-PSU) located at the top of the rack, and in a wall-mount ERn the P-ACP could also get power from an optional Redundant Power Supply (ERn-RPS) located at the bottom of the rack. The ERn power supply (or redundant power supply) receives either 120VAC, 230VAC, or 240VAC power to the rack. Then it converts power to 24VDC, and sends it through a wire harness to the right I/O, and finally to the P-ACP. Typically the issue is more likely to be a faulty power supply rather than the P-ACP, but the troubleshooting instructions below will help narrow down where the issue is.
- Make sure the P-ACP is firmly seated in the rack. It slides in, so just gently push it in to ensure a good connection.
- Is the Rack Power LED illuminated on the PSU and/or RPS? On older units the LED is green, while newer units have a blue LED.
- Usually if the LED is lit that means it's passing power, but that isn't always the case. It's best to continue troubleshooting.
- If an ERn4, and it contains two P-ACPs, are both affected or just one? If just one, this is most likely an issue with that P-ACP. If both are powered off, this is more likely an issue with a power supply.
- Power off the ERn. NOTE: failure to do so for this step can cause serious harm or death to individuals and/or further damage equipment in the ERN. Remove the PSU (and RPS if installed) by twisting the thumb-screws to the left and pulling straight out of the rack. The PSU/RPS has a removable 1.25 Amp fuse that can be checked. The placement is slightly different on 120/240VAC PSU, RPS, and 230VAC PSU. Below is the location on the 120/240VAC variants. If the fuse is blown, there is no spare on the device, so one can be purchased through an ETC Dealer (ETC part number F206-F).
120/240VAC PSU Redundant PSU (RPS) 
- To fully determine if the PSU/RPS is bad, look at the optional Paradigm Station Power Module (P-SPM) and check if its Aux Power and Link Power LEDs are illuminated?
- 120VAC / 240VAC systems: the P-SPM gets its power directly from the rack's source. If the LEDs are illuminated this is a sign the power to the rack is good, so the rack PSU may be faulty. If the LEDs are not illuminated have an electrician check the incoming power to the rack.
- 230VAC systems: the P-SPM gets its power from the rack PSU. If it's illuminated then the circuit on the PSU feeding the P-SPM is good, but the circuit feeding the P-ACP may still be faulty. If no LEDs are illuminated on the P-SPM then the PSU is faulty.
Related Links/References