Puritan Bennett 7200 User manual

SECTION

SECTION

Repair: Power Supply Assembly 11

The power supply assembly is a modular unit that supplies various voltages to the ventilator
electronic system. The power supply assembly consists of a +5 V module, a +12 V module, a
±15 V module, and a power fail module. These modules are individually replaceable. In
addition, depending on ventilator model, the power supply is augmented by a surge
suppressor mounted above the power supply, and/or by a power line filter mounted in the
utility panel. An isolation transformer is installed in later ventilator versions to step the
voltage to the power fail module.

This section describes removal, installation, testing, and adjustment of the power supply
assembly and its components. Before repairing the power supply assembly, familiarize
yourself with the warnings, cautions, and general repair instructions in Section 8.

Warning

• To prevent personal injury and equipment or property damage, ensure that electrical
power sources and pneumatic sources are disconnected from the ventilator before
servicing.

• If ventilator must be serviced with the power on, be careful to avoid electrical shock.
Avoid reaching into the ventilator. Follow accepted safety procedures for electrical

equipment when testing, making connections, adjustments, or repairs.

11

11.1 Testing Output Voltages

The power supply voltages may be tested without accessing the power supply. To test these
voltages, refer to Section 7.6.7 (performance verification).

11.2 Calibration of Output Voltages

1. Calibrate the power supply output voltages as follows, referring to Figure 11-1.

2. Connect ventilator to electrical power. Turn on ventilator power.

3. Calibrate power supply module output voltages by connecting insulated.025 in. square
pin DMM leads to appropriate pins on the motherboard connector J14 as indicated in
Figure 11-1, then adjusting appropriate potentiometer until DMM reads within acceptable
range. Seal potentiometer with torque seal when adjustment is successful.

NOTE:

If adjustment of the applicable potentiometer fails to bring a voltage into its acceptable
range, replace the module or power supply assembly, as appropriate.

4. Turn off power to ventilator. Unplug ventilator power cord.

066317 Rev. A (03/04) 7200 Series Ventilator System Service Manual 11-1

11 Repair: Power Supply Assembly

Power Supply Voltages

Voltage to be
Measured

+5 V R10 Pin 9 Pin 11 +4.95 to +5.05 V

+12 V R12 Pin 13 Pin 11 +11.88 to +12.12 V

+15 V R26 Pin 7 Pin 5 +14.85 to +15.15 V

–15 V R19 Pin 4 Pin 5 –15.15 to –14.85 V

(EMI 7200ae only)
Needs fuse
(4-030230-00) +15 V (R26) –15 V (R19) +12 V (R12)

TRANSFORMER

+15 V / –15 V

5 1 3 2 4

Potentiometer

+Out

+Out –S +S–S–Out

+S

COM

+15 V/–15 V

Positive
Lead

Negative
Lead

TRANSFORMER

4 2 3 1 5

Acceptable Range

+12 V

+Out –S –Out

+S

+12 V

–Out –Out

–Out +S –S

+5 V (R10)

TRANSFORMER

+5 V

(220/240 V only)
ISOLATION
TRANSFORMER

Power Fail Trip Points

Ventilator
Volt age

100 V ac 82 ± 1 V ac 90 V ac

115 V ac 95 ± 1 V ac 103.5 V ac

220 V ac 186 ± 1 V ac 198 V ac

240 V ac 204 ± 1 V ac 216 V ac

Power Fail Trip
Point

POST Value

R14

Power fail module

2-00385

Figure 11-1. Power Supply Voltage and Trip Point Calibration

11-2 7200 Series Ventilator System Service Manual 066317 Rev. A (03/04)

Repair: Power Supply Assembly 11

11.3 Calibration of Power Fail Trip Point

The power fail module monitors the input power to the power supply assembly. If the input
power drops below the power fail trip point for 4 ms to 6 ms, the power fail module generates
a power fail signal, which signals the CPU.

Calibrate the trip point of the power fail module as follows. The calibration requires a variable
transformer (variac) with ground wire. A 0-140 V, 10 A variac is required for 100 and 115 V
ventilators, while a 0-280 V, 5 A variac is required for 220 and 240 V units.

NOTE:

Care must be taken when performing this procedure. When adjusting the variac voltage,
use a slow and steady motion to avoid lowering the voltage below the actual power fail trip
point, thereby invalidating the results.

1. Remove ventilator top and back panels (Sections 19.1 through 19.4), and swing open left­hand panel (Section 9.1, steps 2 through 4). Disconnect all accessories (ac and dc
powered) from ventilator.

2. Connect electrical source to variac and connect variac to ventilator, as shown in Figure
11-2.

3. Adjust output of variac to applicable voltage (100, 115, 220, or 240 V).

4. Switch on ventilator power.

5. Connect DMM leads to a convenient location outside the ventilator in order to monitor
the input voltage, but place the leads as close to the ventilator’s power cord as possible.
Note the DMM voltage reading.

6. Remove DMM leads and place them on the “LINE” side of the surge suppressor, or on the
#2 tabs of the utility panel terminal block (if the unit is not equipped with a surge
suppressor). Note the DMM reading and compare it to the original reading. If the two
readings differ by more than 2 V, inspect terminal block, power cord, relay, and circuit
breaker for signs of oxidation. Clean or replace as necessary to correct.

7. While monitoring input voltage, slowly adjust variac to reduce input voltage until LEDs
on CPU PCB begin to flash. The point where CPU PCB LEDs begin to flash is the power fail
trip point. Verify that the DMM reading is within the applicable power fail trip point
range in Figure 11-1.

8. Raise variac voltage to where Power-On-Self-Test (POST) is initiated. Verify that the DMM
reading is less than or equal to the POST value given in Figure 11-1.

9. Repeat step 7 to verify power fail trip point.

10. Readjust output of variac to applicable voltage (100, 115, 220, or 240 V).

NOTE:

To avoid damaging the power fail trip point adjustment potentiometer (R14), use extreme
care when scraping off the existing torque seal.

11. If necessary, use a long, insulated, flat-bladed screwdriver to adjust power fail trip point
voltage by slowly turning the adjustment potentiometer (R14).

12. Repeat steps 7 through 11 until trip point and POST voltages are acceptable.

13. Seal potentiometer (R14) with torque seal (P/N 4-004017-00).

14. Turn off power switch to ventilator.

15. Disconnect ventilator and variac from wall power.

066317 Rev. A (03/04) 7200 Series Ventilator System Service Manual 11-3

11 Repair: Power Supply Assembly

16. Reattach all panels (Section 19), hardware, and accessories (Section 3) to the ventilator.

17. Connect external pneumatic and electrical sources to ventilator.

18. Refer to performance verification procedures in Section 7 to verify that ventilator
is operational.

Top cabinet
panel

Top cover

ac input

Variac

Voltmeter

Surge
suppressor

Left-hand
panel

Back
panels

Power cord

Figure 11-2. Power Fail Trip Point Calibration Test Setup

11.4 Removal/Installation of Top-Mounted Surge Suppressor

A surge suppressor filters voltage spikes. In those ventilators with a surge suppressor, the 100/
115 V suppressor is always mounted near the top of the ventilator, while the 220/240 V
suppressor may be mounted near the top or it may be integral to the utility panel. The
following subsections discuss the service of top-mounted surge suppressors. Refer to
Section 12.8 to service the 220/240 V surge suppressor integral to the utility panel.

11.4.1 100/115 V Surge Suppressor

Remove the 100/115 V surge suppressor as follows. Install by reversing removal procedures.

1. Remove ventilator top and back panels (Sections 19.1 through 19.4), and swing open left­hand panel (Section 9.1, steps 2 through 4).

2. Disconnect wires that are attached to the surge suppressor “LOAD” terminals from
interconnect harness (if present) or from the surge suppressor (blue wires from “N”, brown
wires from “L1”).

2-00386

11-4 7200 Series Ventilator System Service Manual 066317 Rev. A (03/04)

Repair: Power Supply Assembly 11

3. Pull power supply ac harness down through bottom of surge suppressor bracket. (Note
that harness grommet is removable through slot in the edge of the bracket.)

4. Disconnect the following wires from utility panel terminal block (Figure 11-4):

a. Blue wire in surge suppressor harness from “N1” terminal.

b. Brown wire in surge suppressor harness from “L2” terminal.

NOTE:

The locations of utility panel terminals are shown on the terminal block label on the
ventilator cabinet divider wall.

5. Remove harness from wire clips on ventilator cabinet divider wall, and pull harness up
through bottom of surge suppressor bracket.

6. Remove screw and lock washer that attach front portion of surge suppressor bracket to
ventilator console hinge panel.

7. Loosen two screws (one on either side of surge suppressor assembly) that attach two
suppressor bracket clamps to surge suppressor bracket (Figure 11-5).

8. Remove surge suppressor by lifting its front edge and sliding clamps off rear ventilator
cabinet lip.

FRONT

Surge
suppressor
bracket

Brown
wires

Blue
wires

Green/
yellow
wire

Power supply
ac harness

FRONT

Surge
suppressor
bracket

Brown
wires

Blue wires

Power supply
ac harness

100/115 V Unit 220/240 V Unit

Interconnect
harness
ground wire

2-00387

Figure 11-3. Disconnecting Top-Mounted Surge Suppressor Harness

066317 Rev. A (03/04) 7200 Series Ventilator System Service Manual 11-5

11 Repair: Power Supply Assembly

11.4.2 220/240 V Surge Suppressor

If the 220/240 V surge suppressor is mounted near the top of the ventilator, remove it as
follows. Install by reversing removal procedures.

1. Remove ventilator top and back panels (Sections 19.1 through 19.4), and swing open left­hand panel (Section 9.1, steps 2 through 4).

2. Disconnect wires that are attached to surge suppressor “LOAD” terminals from
interconnect harness (if present) or from surge suppressor (blue wires from “N”, brown
wires from “L1”).

3. Pull surge suppressor harness up through bottom of surge suppressor bracket. (Note that
harness grommet is removable through slot in the edge of the bracket.)

4. Disconnect these wires from utility panel terminal block (Figure 11-4):

5. Blue wire in surge suppressor harness from “N1” terminal.

6. Brown wire in surge suppressor harness from “L2” terminal.

7. Disconnect green/yellow wire from green/yellow power cord ground wire (Figure 11-3).

8. Pull harness up through bottom of surge suppressor bracket.

9. Remove screw and washer that attach front portion of surge suppressor and interconnect
harness ground wire to ventilator console hinge panel (Figure 11-5).

10. Remove surge suppressor by lifting its front edge and sliding clamps off rear ventilator
cabinet lip.

N

1

2

3

4

1

2

3

4

20038 REV A

2-00388

Ground stud

2-00310

L

L

N

DIVIDER WALL

N

SWITCHED

L

SWITCHED

L

UNSWITCHED

N

UNSWITCHED
REAR OF UNIT

Terminal Block Label

Figure 11-4. Disconnecting Harnesses from Utility Panel Terminal Block

11-6 7200 Series Ventilator System Service Manual 066317 Rev. A (03/04)

Repair: Power Supply Assembly 11

11.5 Removal/Installation of Power Supply Assembly

Remove the power supply assembly from the ventilator as follows. Install by reversing
removal procedures.

1. Disconnect power supply ac harness as applicable, depending on configuration:

• From utility panel terminal block (blue wires) from “N1”, brown wire(s) from “L2” as in Figure
11-4.

• From interconnect harness.

• From surge suppressor terminal block

NOTE:

The locations of utility panel terminals are shown on the terminal block label on the
ventilator cabinet divider wall.

2. Remove three screws and washers that attach rear bottom edge of power supply
to ventilator (Figure 11-5).

Warning

The power supply assembly is very heavy. Be careful when lifting the power supply assembly
out of the ventilator.

Surge
suppressor

Suppressor
bracket
clamps

3. Remove the screws to the utility panel and slide it to the left side of the ventilator.

220/240 V
power supply

Power supply
assembly

066317 Rev. A (03/04) 7200 Series Ventilator System Service Manual 11-7

110/115 V
power supply
ac harness

ac harness

2-00389