24 V Power System: Operation and Short-Circuit Diagnosis

The Retro C has two separate 24 V DC control-power systems: one on the stationary end and one on the carriage end. These systems power the VC1 controls and related devices. A fault on one branch can cause every VC1 on that end of the saw to appear offline.

Electrical safety: Troubleshooting inside an electrical enclosure must be performed by qualified personnel. Follow the facility’s lockout/tagout procedure, verify the absence of hazardous voltage, and use the machine schematics before disconnecting or moving conductors.

Common symptoms

• All VC1s on one end of the saw are disconnected or offline.
• The green LED on the 24 V power supply pulses instead of remaining steadily illuminated.
• The controls return when a downstream 24 V branch is isolated.
• The measured control voltage is low or unstable.

How the circuit is arranged

On the stationary side, AC power enters the 24 V power supply on wires 11 and 12. The supply creates the positive and negative 24 V DC rails. The DC OK circuit exits on wire 181 to relay CR29; CR29 should be energized whenever the power supply is operating normally.

The positive output continues on wire 177 to the DC-IN terminals of the DC-UPS. The DC-UPS maintains control power to the VC1s during a power interruption. Its output travels on wire 122 to the blue distribution terminals. Jumpers join the terminal groups and distribute 24 V power to the individual VC1 branches.

Initial checks

1. Identify whether the stationary-side or carriage-side VC1 group is offline. This determines which 24 V system to inspect.
2. Inspect the power-supply LED. A steady green LED indicates normal output; a pulsing LED can indicate an overloaded supply, a downstream short circuit, or a failing supply.
3. Have a qualified technician measure the DC output. The power supply and DC-UPS are configured for 27.4 V DC on this system. Both devices must be adjusted and verified correctly; do not change either adjustment without the correct meter and machine documentation.
4. Inspect the 24 V distribution terminals, jumpers, and field wiring for loose conductors, damaged insulation, metal debris, moisture, or visible heat damage.

Isolating a downstream short

With the machine de-energized and locked out, a qualified technician can isolate groups of 24 V loads at the distribution terminals. Begin with the jumper between the right- and left-side terminal groups. Re-energize only for the required observation, following the approved electrical procedure.

If the supply LED becomes steady after a group is isolated, the fault is on the disconnected side. De-energize and lock out the machine again, then isolate the individual VC1 branches in that group until the affected circuit is identified. If the LED continues to pulse with all downstream loads isolated, inspect the supply, DC-UPS, and upstream wiring.

Correction and verification

• Repair damaged wiring or replace the failed component; do not leave a required VC1 or safety-related circuit disconnected.
• Restore every terminal jumper and conductor to its documented position.
• Confirm a stable 27.4 V DC output and a steady green power-supply LED.
• Confirm CR29 is energized and all VC1s on that end reconnect.
• Cycle the affected functions from the normal controls and confirm that the fault does not return.

For temporary UPS bypass instructions, use How to Bypass the 24 V Battery Power Supply only under Enventek Support direction.