Troubleshooting And Repair Of The F1A4 Control Box; Troubleshooting The F1A4 Control Box - Minelab F1A4 Service Manual

F1A4 Field Service Manual – Level 1 and Level 2 Maintenance
5. TROUBLESHOOTING AND REPAIR OF THE F1A4
CONTROL BOX
This section covers troubleshooting and repair of the F1A4 Control Box,
required after Section 4 testing. After any repair has been completed, return to
Section 4 for a complete test of the F1A4 Control Box.
5.1

TROUBLESHOOTING THE F1A4 CONTROL BOX

5.1.1 Initial Power On Troubleshooting
5.1.1.1 Power On Test Procedure
Connect the F1A4 to a good Coil and charged battery pack.
Note: The Coil must not be near any metal objects, and the
technician must not wear any rings, bracelets, or watches
during this procedure.
Switch the F1A4 on to the Search position. The detector should take 6
seconds to run through the start up routine, comprising four rising tones, followed by
a continuous background threshold tone.
If the tones or threshold tone are distorted, the loud speaker maybe defective. Go
to 5.2.1 for the loudspeaker replacement procedure.
If there are still no tones or threshold, ensure that the batteries and battery carrier
are good (if in doubt, substitute known good batteries and/or battery carrier).
If there are still no tones or threshold tone, connect an Earset. If tones or the
threshold tone are now heard through the Earset go to 5.1.1.2. If no tones or
threshold are heard through the Earset go to 5.1.1.3.
5.1.1.2 Audio Troubleshooting
Remove the 6 screws from the front panel and pull the front panel away from
the case. Desolder the 2 wires from loudspeaker. With a multimeter, measure
resistance of loudspeaker. Resistance should read approximately 15 ohms. If the
resistance reading is incorrect, the loudspeaker is defective, go to 5.2.1 for the
loudspeaker replacement procedure. If the resistance is OK, check wiring from the
PCB to the speaker and earset jack and repair as necessary.
to be OK, the PCB is defective. Go to 5.2.4 for the PCB replacement procedure.
5.1.1.3 Off/Search/Balance Switch Troubleshooting
Remove the 6 screws from the front panel and pull the front panel away from
the case. With a multimeter, measure the circuit of the Off/Search/Balance switch
(refer Section 7 for switch circuit details). If the switch does not measure correctly,
the switch is defective, go to 5.2.2 for the Off/Search/Balance switch replacement
procedure. If the switch measures OK, check wiring from the PCB to the
Off/Search/Balance switch and Power Plug and repair as necessary. If the wiring if
found to be OK, the PCB is defective. Go to 5.2.4 for the PCB replacement
procedure.
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If the wiring if found