Philips Fm2 Service Manual

							Tools Required
Chapter 6 - Disassembly/Reassembly Guide
39
All part numbers and exploded views of some assemblies are found in 
Chapter 7,“Spare Parts”.
Tools Required
Caution
When reassembling, be sure to follow torque-limits instructions. Excessive 
torque may damage the plastic screw mountings or case.
The following tools are required:
small/medium, Phillips-head screwdriver
A torque-sensitive tool, with a torque range to 1.1 Nm (10 in-lb.); accuracy 
±0.1 Nm (±1 in-lb.)
needle-nose pliers or Tinnerman tool
10 mm socket driver (for wheel encoder nut)
3/16” socket driver
The rear case assembly consists of a molded plastic case, in which the battery is 
stored. The speaker housing is mounted on the back of the rear case assembly, 
and also forms the cover for the battery. Through-holes in the case cover are 
provided for the rear-panel connectors, that are mounted on the rear connector 
board.
Fuses
There are no customer or field-replaceable fuses. 
						

							Closed Case Disassembly/Reassembly Procedures
40Chapter 6 - Disassembly/Reassembly Guide
Closed Case Disassembly/Reassembly Procedures
This section describes the items that may be removed without disassembling the 
main case of the monitor.
The speaker housing is attached to the back of the rear case. The speaker 
housing also acts as the battery cover. To gain access to the battery, first remove 
the speaker housing (see “Removing the Speaker Housing” on page 41).
Caution
Important for disassembly! When disassembling the monitor, make sure 
that the battery leads are disconnected. Otherwise, it is likely that circuit 
damage will occur.
Caution
Important for reassembly! If the internal battery cable has been 
disconnected, pay very careful attention to the polarity of the cable before 
reattaching. The red wire connects to the +ve terminal, the black wire 
connects to the -ve terminal. If the battery cable polarity is reversed, circuit 
damage will occur. Circuit damage caused by reversed polarity is not 
covered by the warranty. 
						

							Closed Case Disassembly/Reassembly Procedures
Chapter 6 - Disassembly/Reassembly Guide
41
Removing the Speaker Housing 
Step 1. Place the monitor on its front panel, being careful not to place the unit 
on any surface that will damage the display.
Step 2. Using the Phillips-head screwdriver, unfasten the two screws securing 
the speaker housing. The speaker housing also acts as the battery cover.
Step 3. Gently lift the bottom (screw) end of the speaker cover just enough for 
the battery pad (attached to the inside of the speaker housing) to clear 
the bottom of the rear case. At the same time, slide the speaker housing 
towards the bottom of the rear case to free the two lugs holding the top 
of the speaker housing. The speaker housing is now free of the rear 
case, but with the wires still connected.
Step 4. Carefully disconnect the speaker wires by sliding the spade connectors 
off the speaker terminals.
Step 5. The speaker housing is now completely free of the rear case. 
						

							Closed Case Disassembly/Reassembly Procedures
42Chapter 6 - Disassembly/Reassembly Guide
Replacing the Speaker Housing 
Step 1. Connect the speaker cables by pushing the spade terminals onto the 
speaker terminals in the speaker housing. Check that they are secure. 
The wires are not coded for polarity, as the polarity is uncritical.
Step 2. Refit the speaker housing by sliding the two metal lugs at the top end 
of the speaker housing under the lip at the top of the battery housing 
aperture until it stops.
Step 3. Secure the speaker housing with the two fastening screws. Torque the 
screws to 0.7 to 0.9 Nm (6 to 8 in. lb).
Caution
Do not overtorque the screws, as the plastic screw mountings or the casing 
may be damaged.
Speaker housing
lugs
Speaker
terminals 
						

							Closed Case Disassembly/Reassembly Procedures
Chapter 6 - Disassembly/Reassembly Guide
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Removing the Battery 
Step 1. Place the monitor upside down so that its top is resting on the work 
surface. In this position, the monitor leans back at a convenient angle 
that allows easy removal of the battery with the aid of gravity.
Step 2. While the monitor is in this tilted position, the battery will normally 
fall partly out of its housing. If it does not, then apply a little pressure 
on the terminal-end of the battery (nearest the work surface). This 
should cause the battery to fall partly out of the case.
Step 3. Carefully remove the battery from the monitor. Take care not to put 
too much stress on the battery wires as you take the battery out of the 
case.
Step 4. Disconnect the battery cables by sliding the spade connectors off the 
battery terminals.
Caution
During reassembly, pay very careful attention to the polarity of the battery 
cable before reattaching. The red wire connects to the +ve terminal, the 
black wire connects to the –ve terminal. If the battery cable polarity is 
reversed, circuit damage will occur. Circuit damage caused by reversed 
polarity is not covered by the warranty. 
						

							Closed Case Disassembly/Reassembly Procedures
44Chapter 6 - Disassembly/Reassembly Guide
Replacing the Battery 
Step 1. Connect the battery cables to the replacement battery, paying careful 
attention to cable polarity. Connect the red cable to the positive 
terminal, marked in red. Connect the black cable to the negative 
terminal, marked in black.
Step 2. Carefully place the new battery into the battery housing.
Step 3. Reconnect the speaker and refit the speaker assembly. (See “Replacing 
the Speaker Housing” on page 42).
Battery Disposal
Refer to practices and procedures used at the local institution when disposing of 
the battery.
Please conform to any local laws and requirements governing the disposal of lead 
acid batteries. 
						

							Separation of Front and Rear Case Assemblies
Chapter 6 - Disassembly/Reassembly Guide
45
Separation of Front and Rear Case Assemblies  
Separation
This section describes the procedures required to separate the front and rear case 
assemblies of the FM-2 monitor.
Step 1. Remove the speaker housing (see “Removing the Speaker Housing” on 
page 41).
Step 2. Remove the battery (see “Removing the Battery” on page 43).
Step 3. Remove the four screws fastening the rear case assembly to the front 
case assembly using a Phillips-head screwdriver.
Step 4. Separate the front and rear case assemblies.
Note—The US and Toco sockets protrude slightly from the face of 
the connector panel on the side of the monitor. While separating the 
front and rear case assemblies, you may feel some resistance at the 
connector panel end of the monitor, in which case gently raise the 
handle end of the rear case assembly to help to clear the sockets.
Step 5. If the silicone tubing seal is to be replaced, remove it.
Rear case
assembly
Connector panelGrooveFront case
assembly 
						

							Separation of Front and Rear Case Assemblies
46Chapter 6 - Disassembly/Reassembly Guide
Reassembly
Step 1. Ensure that the cables for the speaker and the battery are correctly 
routed and accessible from the rear of the case for later connection.
Step 2. Confirm that the patient connector PCB is firmly mated to the main 
PCB. (There should be no gap between the bottom of the patient 
connector PCB and the main PCB).
Step 3. Carefully align the groove in the connector panel with the edge of the 
corresponding opening in the rear case moulding. Take care that it 
stays aligned while you push the front and rear case assemblies 
together. When the reassembly is complete, the edge of the case 
opening should sit evenly in the groove of the connector panel.
Step 4. Align the ridge in the front case assembly with the groove in the rear 
case assembly.
Step 5. Check that the four screw holes align correctly.
Step 6. Drive in the four screws that hold the front and rear assemblies 
together. Torque the screws to 0.7 to 0.9 Nm (6 to 8 in. lb).
Caution
Do not overtorque the screws, as the plastic screw mountings or casing 
may be damaged.
Step 7. Refit the battery (see “Replacing the Battery” on page 44).
Step 8. Refit the speaker housing (see “Replacing the Speaker Housing” on 
page 42). 
						

							Front Case Disassembly/Reassembly Procedures
Chapter 6 - Disassembly/Reassembly Guide
47
Front Case Disassembly/Reassembly Procedures 
This section describes how to remove/replace items from the front case assembly.
The front case assembly includes the replaceable molded front-case, the main 
PCB, the LCD assembly, the front-panel keypad and the navigation wheel.
First separate the front and rear case assemblies as described in the section 
“Separation of Front and Rear Case Assemblies” on page 45.
Removing the Navigation Wheel 
The wheel is a friction fit on the stem of the encoder. The encoder is attached to 
the main circuit board and has a threaded moulded base just below the rotating 
stem of the encoder. The threaded base accepts a 10 mm nut which fastens the 
encoder assembly to the front bezel.
Step 1. From the front, remove the wheel by grasping the sides of the wheel 
firmly and pulling straight back from the monitor.
If the wheel is not easily removable by hand, a small flat-headed 
screwdriver may be used to gently pry off the wheel. If necessary, apply 
some adhesive tape to the front cover and/or the head of the 
screwdriver to prevent any damage.
Step 2. Use a 10 mm hex socket or suitable closed spanner to unscrew the 
fastening nut on the outside of the front bezel.
Encoder shaft
10 mm nut 
						

							Front Case Disassembly/Reassembly Procedures
48Chapter 6 - Disassembly/Reassembly Guide
Replacing the Navigation Wheel 
Step 1. If the front case assembly has been disassembled, refit the LCD 
assembly (see “Replacing the LCD Assembly” on page 51) and the 
main circuit board (see“Replacing the Main PCB Assembly” on page 
52) to the front case assembly.
Step 2. Screw the 10 mm nut onto the threaded base of the encoder switch 
from the outside of the front bezel, initially by hand.
Caution
Do not overtorque. If excessive torque is applied to the encoder nut, 
damage will occur to the encoder switch. Do not exceed the maximum 
allowable torque setting.
Step 3. Using a torque-sensitive tool, torque the nut to 0.2 Nm (28.3 oz. in.).
Step 4. Push the navigation wheel onto the shaft of the encoder.