DHG Dyna-Form Mercury Advance Service Manual page 11

9.6 Opening the Control Unit
To remove the front of the enclosure,first unscrew the four corner screws (marked A).
9.7 System Layout
1. Control PCBA
2. Compressor
3. Air outlets
4. Rotor valve
5. IEC power inlet
6. Rotor valve motor
7. Micro switch
9.8 Checking the System
1. Plug in the mattress to the Control Unit.
2. Plug in the mains cable to the IEC inlet and switch on the power.
3. The LED indication LOW and HIGH pressure will flash during start up.
4. The Control Unit will run until the mattress is inflated to the preset pressure setting (LOW).
5. The LED indicating the setting (LOW) will be lit.
6. The system is ready to use.
7. The system is designed so the Control Unit sets the pressure as required and will run for short
periods of time to maintain the required pressure or alter it when moving from LOW to HIGH.
9.8.1 Checking LEDs, Buttons and Sounder
1. Disconnect the tube from Compressor. This will illuminate LED C. Reconnect the tube to the
Compressor.
2. Disconnect the Mains Rotor Wire from the PCB. This will illuminate LED A and B after 5-10 minutes.
Reconnect the Mains Rotor Wire to the PCB.
3. Press both buttons on top of the control unit and hold for 3 seconds. This will illuminate the Service
Light LED and an audible sound will confirm both buttons are working. Press and hold both buttons
again for 3 seconds to extinguish the Service Light LED.
9.9 PCBA Replacement
1. Release the four fixing screws from the rear of the unit connecting the case front and rear together.
Retain screw for reassembly (see 9.6 Opening the Control Unit).
2. Pull sensor tube off pressure sensor and remove cable tie and cut cable tie off switch wire header
and disconnect switch wire.
3. Disconnect the rest of the wire headers from the PCB.
4. Disconnect the Mercury Advance membrane 14 way single row header from the PCB.
5. Release the three fixings securing the faulty PCB to the front enclosure. Retain the fixings for
reassembly. Remove the faulty PCB by sliding forwards towards the edge of the front enclosure away
from the retaining posts.
6. Side new PCB into position so it is lined up with the two fixing holes and it is secured by its retaining
posts.
7. Secure new PCB into front enclosure using two fixings retained from disassembly.
8. Connect pressure sensor tube to pressure sensor on PCB and apply cable tie.
9. Connect switch header from IEC to the PCB and apply cable tie.
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