Malfunction Fan Control board or SMPS board.

Measure on the Signal Backplane the +24V voltage on pin 9, 10, 11 or 12 of the connector of the black wire unit which comes from the SMPS board. See image.

If the measured voltage is about 24V then replace the Fan Control board. See "Replacement of a Card Cage board". Otherwise replace the SMPS board. See "Replacement of the SMPS board".

Short circuit or bad connection.

1. Check the Signal Backplane for bad connections. Ensure that all wire units are well connected.

   (Note that the +24V supply is generated on the SMPS board and enters the Fan Control board and Cinema Control board via the Signal Backplane)

2. Check the wiring (reference 1 image) of the Anode fan (reference 2 image) for short circuits.

3. Check the wiring (reference 3 image) of the Cathode fan (reference 4 image) for short circuits.

Damaged insulation of the wire unit (reference 1 & 3 image) of the SMPS fans (reference 2 & 4 image).

Check the insulation of the wire unit of the SMPS fans. The two SMPS fans are located behind the front filter (two lower fans).

1. Repair the insulation of the wire unit using shrink sleeve.

2. If not repairable replace the Cathode fan.

Malfunction Signal Backplane (bad connection)

Replace the Signal Backplane.