MicroRint - ServiceManual
046-22 Iss. 1.0 June 1998
Contents
System Overview.........................................................................................................2
Figure 1 .......................................................................................................................2
Disassembling the MicroRint Computer for Circuit Investigation .......................... 3
Reassembling the MicroRint Computer ...................................................................4
Disassembling the Interrupter Transducer for Circuit Investigation......................5
Reassembling the Interrupter Transducer................................................................6
Circuit Description-Microcomputer
Overview.......................................................................................................................7
Address Bus............................................................................................................................................7
Reset.......................................................................................................................................................7
Keypad....................................................................................................................................................7
Real Time Clock......................................................................................................................................8
Display.....................................................................................................................................................8
Battery Monitoring...................................................................................................................................8
Power Supply..........................................................................................................................................8
Circuit Description-Interrupter Transducer
Overview....................................................................................................................... 9
Power supply ..........................................................................................................................................9
Battery monitor........................................................................................................................................9
Pressure monitor.....................................................................................................................................9
Shutter operation ....................................................................................................................................9
Parts List - MicroRint Computer ..............................................................................10
Parts List - Interrupter Transducer..........................................................................12
Technical Support.....................................................................................................14
Fault Analysis............................................................................................................15
Circuit Diagram - MicroRint Microcomputer...........................................................16
Circuit Diagram - Interrupter Transducer................................................................17
1
MicroRint Microcomputer - System Overview (Fig. 1)
Fig. 1
The Micro Medical MicroRint is a data recording airways resistance meter consisting of a
microcomputer unit (1) incorporating an LCD graphic display, data entry keypad, RS232 serial
interface and all associated circuitry. This is supplied with an interrupter transducer (2), resistive
element holder (3) resistive element (4) Pressure calibration adapter (5) and Mouthpiece adapter (6).
The MicroRint is powered by internal rechargeable Nickel Cadmium cells or by the mains adapter
supplied.
The interrupter transducer is used to measure the subject’s airways resistance in accordance with the
operating manual.
MicroRint
2
CHARGING
1
MicroRint
S
C
1
A
L
E
4 5
7 8
CHARGING
SCROLL
2
3
6
9
0
ON
OFF
DELETE
ENTER
3 4
5
6
2
Disassembling the MicroRint Computer for Circuit Investigation
1. Disconnect all mains power supplies
We recommend that you use a Philip Number Zero screwdriver for the
following instruction.
2. Place the MicroRint face down to remove the two screws in the lower moulding, and put the
screws to one side.
3. Turn the unit face up and ease the upper and lower mouldings apart by lifting the top moulding at
an angle as illustrated in the diagram below until it becomes loose.
4. Reconnect mains power supply
5. The MicroRint is now ready for Circuit Investigation.
If you are not familiar with the operation of the MicroRint please read the
following section in this manual ‘Circuit Description’ and use the Circuit
diagrams at the back of this manual.
Top moulding
Locating
lugs
Battery pack
2 off screws
Display
Bottom moulding
3
Reassembling the MicroRint Computer for Ready for Operation
Top moulding
Locating
lugs
Battery pack
2 off screws
1. Replace printed circuit board (If removed during investigation) into the bottom moulding.
2. Place the top moulding locating lugs into the bottom moulding at an angle as illustrated above.
3. Push the top moulding together with the bottom moulding making sure that there are no wires
caught between the top and bottom moulding.
We recommend that you use a Philip Number Zero screwdriver for the
following instruction.
4. Turn the unit face down and insert the two screws into the bottom moulding and secure.
5. The unit will now require calibration - Refer to operating manual.
Display
Bottom moulding
4
Disassembling the Interrupter Transducer for Circuit Investigation
1. Disconnect the Interrupter Transducer from the MicroRint Computer
2. Remove the Resistive element holder and put to one side.
3. Remove the four rubber feet and put to one side.
RESISTIVE
ELEMENT
HOLDER
FOUR
RUBBER
FEET
Fig 2
We recommend that you use a Philip Number Zero screwdriver for the
following instruction.
4. Remove the four screws located under the rubber feet and put to one side.
5. Ease the moulding apart to reveal the circuitry.
6. The Interrupter Transducer is now ready for fault finding.
If you are not familiar with the operation of the MicroRint please read the
following section in this manual ‘Circuit Description’ and use the Circuit
diagrams at the back of this manual.
5
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