Fisher & Paykel MR730, MR720, MR480, MR700 technical manual Fault Location

Page 25

19

7.4.1HEATERPLATES WITH SCREW-IN STANDOFFS

For products after S/N:9773XXX19731, the heaterplate standoffs were changed to shoulder bolts that screwed directly into the heaterplate.

When fitting these heaterplates,‘click’ the heaterplate springs into the recesses on the heaterplate (by rotating them while pushing down), then align the springs with the holes in the case front and screw in the self tapping standoffs into the heaterplate.

7.5FAULT LOCATION

If neither the digital display nor any of the front panel LED’s are on and no power appears to be reaching the transformer primary, check that the mechanical overheat protector on the heaterplate has not cut out. This may be checked by depressing the red reset button. (See § 7.4).

Determine if all power supplies are operational and all fuses are intact. If the power supplies are OK but the display is blank, check the watch dog output (pin 12, U5g). A high output here will blank the display, turn on the humidifier fault LED indicator and isolate the heater circuits but not necessarily stop the processor. Check for the presence of a 33 to 40 ms period square wave at PB7 (pin 1 U5b). If the watch dog output is high and the 33 to 40 ms clock is present a fault in the watch dog circuitry is indicated but if port PB7 is not changing state there is a fault elsewhere.

7.6SCREW TORQUE SETTINGS

Below is a guide to screw torques used on the humidifier, use this as a guide for tightening of screws on the humidifier (exact torques are not required).

Ref

Screw

Application

Driver

Torque(in/oz)

Torque

 

 

 

 

 

(Nm)

 

CHASSIS

 

 

 

 

14

Screw #8 x ½" Pan Phil TY25 S/S

Case Front/Body

Phillips

85-113

0.6 to

 

 

 

 

 

0.8

18

Screw M4 x 8 Pan Phil Taptite

Chassis Earth Screws

Phillips

240-270

1.7 to

 

 

 

 

 

1.9

21

Screw M6 x 25 Csk Allen S/S

Mounting Bracket

Allen

248-276

1.75 to

 

 

 

 

 

1.95

22

Screw M4 x 14 Pan Pozi Taptite

Mains Cord Clamp

Pozidriv

198-240

1.4 to

 

 

 

e

 

1.7

26

Screw M6 x 16 Allen S/S Button

Chassis Earth Screw

Allen

248-276

1.75 to

 

Head

 

 

 

1.95

27

Screw M3 x 5 Pan Phil Taptite

Heaterplate Standoffs

Phillips

99-113

0.7 to

 

 

 

 

 

0.8

 

HEATERPLATE

 

 

 

 

2

Screw M4 x 8 Pan Phil Taptite

Heaterplate

Phillips

212-254

1.5 to

 

 

Earth/Element

 

 

1.8

5

Screw M3 x 5 Pan Phil Taptite

Thermistor/Thermostat

Phillips

99-113

0.7to 0.8

 

 

Heaterplate

 

 

 

Ref. 185040646 MR730/720/700/480 Technical Manual ¯ Revision F ¯ Issued March 2001

Image 25
Contents Auckland, New Zealand D E L S MR730 MR720 MR700 MR480National Office Revision F changes Section Description of ChangeContents Performance Check MR480 Dual Probe Temperature TestMaintenance Schedule B1.1 Power PCB Harness Connection DiagramMaintenance Schedule Checklist 10.1Appendix D Models MR730/720/700 MR700 Series General SpecificationsSET EOHTOP RSDMR700 Series Humidifiers with Version 1.0 Software Operating Controls and ModesStandby Button MR700/720/730 only 1 MR700/MR730 ALL Software VERSIONS, MR720 Version 1.0 only 2 MR720 Version 2.0, 3.0 SoftwareAlarms and Indicators Version 3.0 Software Version 1.0 and Version 2.0 SoftwareAudio Alarm Circuit Operation Power Line Interrupt Revisions D/F Pcbs Revision H and J Pcbs For models with Revision D PCB and earlier CalibrationPage Performance Check Alarms Check MR700/720/730 Dual Probe Temperature Test Servicing Information Replacing revision F or earlier power PCB MR700/720/730Replacing revision F or earlier power PCB MR480 Fault Location SCHEMATICS, Part Lists and Mechanical Drawings Power Board Control Board Component Layout Revision F PCB Page This page Left Blank Circuit Diagrams Revision H and J PCB Control PCB Circuit Diagrams Revision H and J PCB Power PCB Circuit Diagrams Revision F PCB Control PCB Circuit Diagrams Revision F PCB Power PCB LED1, LED3 DSP1, DSP2, DSP3LED2,LED4, LED5,LED11 LED6,LED7 LED8,LED9,LED10SPK1 SW5VR1 VR4Fuse fast acting 2 a 20 × 5 mm for 230 999830009 MR480AGM Exploded Diagrams MR480 10.3 MR730/720/700 Mechanical Parts MR720ASU Exploded Diagrams MR730/720/700 Heaterplate Assembly Parts MR730/720/700/480 Page PCB Identification Diagram Power PCB Harness Connection Diagram Date Change First Serial Number Comments Affected Product Change HistoryYear Model Code Serial Number AAA XxxxxOFF Appendix aA2.3 Integral Display Error MessagesEP2 EP1EP3 EP4Second Byte First ByteThird Byte A5.4 Serial Data Interface Connector Appendix B B1 Maintenance ScheduleElectrical Safety Checks as required Photocopy and File in Maintenance RecordsPossible cause Action to take Appendix CHigh Temperature C1.6 C1.5LED on Check Voltage Rating Of Unit Appendix D Cleaning instructionsAppendix E Setup NotesDynamic Test Sequence MR730/720/700 Dynamic Test Procedure MR480