No Power to Echo Architectural Control Processor in DRd
Issue
The screen is blank on the Architectural Control Processor (no backlight, and no visible text), and no LEDs to the left of the screen are lit.
Explanation
This means the Architectural Control Processor (ACP) at the bottom of your DRd is not powered. If the rack was working before, the first question to ask is if there was recently a power event. Power events can negatively affect different parts of the rack.
The ACP receives power from the Dimming Engine module at the top of the DRd rack. The Dimming Engine receives either 120VAC, 230VAC, or 277VAC power to the rack. Then it converts power to 24VDC, and sends it through a ribbon cable, signal distribution (distro) card, and right I/O to the ACP. The troubleshooting instructions below will help narrow down where the issue is.
- Make sure the ACP is firmly seated in the rack. It slides in, so just push it in to ensure a good connection.
- Fully power down the rack using the circuit breaker, for 1 minute then restore power to see if the ACP energizes.
- Turn the Dimming Engine into TEST mode using the test switch in the bottom-right corner of that module.
- If all of the signal lights on the ride side of the dimmer modules in the rack, and all of the lights in the actual space come on, the dimming engine is still receiving power from its power source. One of three scenarios could be the problem. Usually either of the first two is the issue. It's rare for the ACP itself to be dead.
- A connection between the Dimming Engine and the ACP is bad (such as the ribbon cable, signal distribution card, or right I/O).
- The Dimming Engine may not be passing the 24VDC to the ACP and it needs to be repaired.
- The ACP itself is dead.
- If no signal lights come on, the Dimming Engine is likely damaged in some form and might need repair. NOTE: the next two steps require powering off the DRd. Failure to do so can cause serious harm or death to individuals and/or further damage equipment in the DRd.
- 120VAC dimming engines have a removable 1.25 Amp fuse that can be checked on the left side of the unit next to the power harness connection. If this fuse is blown the Dimming Engine will not function. Position F1 on the PCB is the fuse in use. A spare is located next to it at position F4.
- 230VAC and 277VAC dimming engines have three fuses next to the power harness connection, but are soldered onto the PCB and require being sent in for repair if any of these fuses are blown.
- 120VAC dimming engines have a removable 1.25 Amp fuse that can be checked on the left side of the unit next to the power harness connection. If this fuse is blown the Dimming Engine will not function. Position F1 on the PCB is the fuse in use. A spare is located next to it at position F4.
- If all of the signal lights on the ride side of the dimmer modules in the rack, and all of the lights in the actual space come on, the dimming engine is still receiving power from its power source. One of three scenarios could be the problem. Usually either of the first two is the issue. It's rare for the ACP itself to be dead.
- To fully determine if the Dimming Engine is dead or incoming power to the rack is bad, look at the optional Station Power Module (SPM) that would live above the ACP. It gets the same incoming AC power as the Dimming Engine. If the SPM's LEDs are on, the dimming engine needs repair. If the SPM's LEDs are off and the TEST option does not work, have an electrician check incoming power to the rack.
