Table 3-3. M43 Detector Unit Troubleshooting Table

TM 3-6665-225-12

tions and corrective actions in the order listed.

functions that may occur or all tests or inspections and

corrective actions. If a malfunction is not listed (except

3-8. Disposition of Defective Parts

when malfunction and cause are obvious), or is not cor-

a. When substitution of a replacement pump assem-

rected by listed corrective actions, you should notify

bly or electronic module during a test or inspection cor-

higher level maintenance.

rects the malfunction, do not discard, but return the

original component to organization maintenance

c. Table 3-3 and table 3-4 list the common malfunc-

through your supervisor.

tions that you may find during the operation or mainte-

b. Dispose of all other defective components in accor-

nance of the M43 detector unit and the M42 alarm unit,

dance with local standing operating procedures (SOP).

respectively. You should perform the tests or inspec-

Table 3-3. M43 Detector Unit Troubleshooting Table

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

1. SOLUTION IN BOTTOM CASE ASSEMBLY

Step 1. Check for loose reservoir assembly.

a. Tighten reservoir assembly using D-ring (fig. 2-3).

b. If damaged, prepare solution and install new reservoir assembly (para 2-7b and c).

Step 2. Check for loose or damaged pump assembly.

a. Secure latches.

b. If damaged, replace pump assembly (para 3-14).

Step 3. Check for improperly installed or damaged detector cell.

a. Tighten bail (9, fig. 1-3).

b. If damaged replace detector cell (para 3-12).

2 HORN DOES NOT SOUND WHEN POWER SOURCE IS CONNECTED

Step 1. Check that ZERO ADJUST knob is fully clockwise and HORN VOL-BATTERY TEST control knob is fully clockwise when power

source is connected.

a. Disconnect power source.

b. Press in and rotate ZERO ADJUST knob (5, fig. 2-1) fully clockwise and HORN VOL-BATTERY TEST knob (6) fully clock-

wise.

c. Wait one minute before reconnecting power source.

Step 2. Press HORN VOL-BATTERY TEST knob (6, fig. 2-1); METER indication must be 24 minimum. If less than 24, proceed as

follows:

a Substitute fresh BA3517/U battery or freshly-charged BB501/U battery. Refer to table 1-2 for proper battery applications at

various temperatures.

b. Replace electronic module (para 3-13).

Step 3. Inspect cables for frayed or broken insulation, bent or broken connector pins, or other damage that could prevent proper opera-

tion. Replace defective cables.

Step 4. Check ambient air temperatures

If temperature is below 40F., perform startup procedures to warm up M43 detector unit.

3. HORN CONTINUE TO SOUND WHEN ZERO ADJUST KNOB IS PRESSED IN.

PUMP ASSEMBLY DOES NOT OPERATE.

Step 1. Check that electronic module (10, fig. 1-3) is securely installed

Remove and reinstall electronic module (para 3-13).

Step 2. Temporarily substitute replacement electronic module for electronic module in use (pare 3-14).

If malfunction is corrected, leave replacement electronic module installed. If not, reinstall original electronic module.

4. PUMP CONTINUES TO OPERATE WHEN HORN SOUNDS

Step 1. Temporarily substitute replacement pump assembly for pump assembly in use (para 3-14).

If malfunction is corrected, leave replacement pump assembly installed. If not, reinstall, original pump assembly.

Step 2. Temporarily substitute replacement electronic module for electronic module in use (para 3-13).

If malfunction is corrected, leave replacement electronic module installed. If not, reinstall original electronic module.

5. PUMP DOES NOT OPERATE WHEN ZERO ADJUST KNOB IS PRESSED IN.

Step 1. Temporarily substitute replacement pump assembly for pump assembly in use (para 3-14).

If malfunction is corrected, leave replacement pump assembly installed. If not, reinstall original pump assembly.

Step 2. Temporarily substitute replacement electronic module for electronic module in use (para 3-13).

If malfunction is corrected leave replacement electronic module installed. If not, reinstall original electronic module.

6. MET'ER INDICATES MORE THAN 40 VOLTS WHEN HORN-VOL BATTERY TEST KNOB IS PRESSED IN.

Step 1. Check that knob is pressed in completely.

Step 2. Substitute known good power source and press in HORN VOL-BATTERY TEST knob to check reading.

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