As dimmer racks age, the most common points of failure include the processor, cooling system (fans), and dimmer modules. Fortunately, many racks can be upgraded or repaired — including models from Strand Lighting, Electronics Diversified (EDI), ETC, Entertainment Technology (Lightolier), Colortran (Leviton), and Electro-Controls. If you’re working with legacy EDI systems, it may be time to explore EDI dimmer rack upgrade options to ensure continued performance and safety.
Processor Failures
The processor is the heart of a dimmer rack. It houses most of the system’s electronics in a single module or assembly. When it fails, symptoms vary by manufacturer but often include:
- Lights stuck on at full, with the “Panic” light active
- All lights stuck off
- Flickering or unresponsive lights
- Garbled or unreadable processor display
- Dim or blank processor display
- One or more phase LEDs (A, B, C) are off
Rebooting the rack might temporarily fix the issue — but it’s not a solution. In fact, each power cycle risks total processor failure. Once the processor starts failing, it won’t improve on its own. If you’re experiencing these symptoms, visit our guide to EDI upgrades to see how a replacement processor can bring your system back online quickly and reliably.
Cooling and Fan Failures
Cooling fans are critical for proper operation, especially in racks like CD80SV, iSeries, Capio, Sensor, Mark VII, and MX. Some systems, such as ETC Sensor or Colortran iSeries, rely on pressurized plenums and won’t function unless:
- All module slots are filled
- The filter is clean
- The rack door is closed
Common signs of fan or cooling failure:
- Fans are louder than usual (grinding or thumping sounds)
- Fans are silent (not operating)
- OverTemp LED is lit, and lights won’t turn on
- Trouble indicator LED is lit or blinking
- Processor displays an error code, lights will not turn on.
- Lights shut off shortly after powering on
Proper airflow is essential to maintaining your dimming system’s longevity. If you’re unsure where to start, learn more about our EDI upgrade services to see how cooling system improvements and processor replacements can extend the life of your rack.
Dimmer Module Failures
Dimmer modules degrade over time — especially when exposed to overloads or short circuits caused by faulty cables or miswired plugs.
Symptoms include:
- Circuit won’t turn on, but works when a “known good” module is swapped in
- Circuit won’t turn off, but works when a “known good” module is swapped in
- Breaker trips (don’t swap modules until you’ve confirmed there’s no dead short on the circuit)
How Parlights Can Help
Parlights stocks replacement fans, SSR/power handling devices, and dimmer module parts for a wide range of rack manufacturers. We also offer tested, refurbished dimmer modules ready to swap in.
Need to get back online quickly? Parlights Service Technicians can diagnose, clean, and service your dimming system. If your processor has failed, we offer OEM and third-party replacements — and for many systems (Strand CD80SV, Strand C21, EDI MX, ETC Sensor), we have loaner processors available for immediate deployment.
Upgrades: New Life for Older Systems
While dimmer rack processors have evolved since the 1980s, the core components they control remain largely unchanged. Systems like Strand C21 (RigRack) and ETC Sensor 3 use the same architecture as their 30-year-old predecessors — centralized processors controlling removable dimmer modules with passive components.
That means many older racks can be modernized — replacing the processor, fans, and adding relay or power-thru modules for LED loads — at a fraction of the cost of full replacement. The savings can be invested in LED fixtures, moving lights, and updated data distribution.
Processor Upgrade Options
- Strand (CD80, CD80AE, CD80SV, C21) and ETC (Sensor, Sensor+, Sensor 3) racks have new processors available from the original manufacturer.
- EDI (Mark VII, MX), Colortran (iSeries, iSeries e), and Electro-Controls (EC-Quad) can be retrofitted with processors from JSI Manufacturing (Johnson Systems).
- Parlights also provides custom retrofits for Colortran D192 and Lightolier/Entertainment Technology Capio and Capio+ racks.
When upgrading a processor, technicians should:
- Thoroughly clean the rack and modules
- Confirm all line/load connections
- Visually inspect for physical damage
- Perform a full “slot test” to ensure all circuits respond
- Inspect and replace fans as needed
A properly installed processor upgrade can extend the rack’s life by 15 years or more, adding features like Ethernet control and web-based configuration.
Upgrading to LED-Compatible Modules
Replacing dimmer modules with relay or power-thru modules allows circuits to deliver constant power — ideal for LEDs and moving lights. Options include:
- Strand and ETC relay modules for legacy and current racks
- JSI relay modules for Colortran iSeries and Strand CD80/CD80SV
- Parlights VisionLynx conversion kits for EDI MX and Mark VII
Many LED houselights also require trailing-edge dimming — a specialty of ET Capio racks. Options include:
- Strand IGBT modules (CD80SV, C21)
- ETC LED dimming modules for Sensor
- JSI LED dimmer modules for various systems, including CD80SV
Get Expert Help
Parlights offers repair, retrofit, and upgrade services for most dimming systems.
See our EDI Upgrades services or contact our service team.
📞 Call us: 301.698.9242
📧 Email us: service@parlights.com