AFG/AFTI Mk 4
Service and Repair Manual
Number 022-614
Issue Number: 09
Page 39 of 47
25. Fault finding.
Gauge Fault
Remedy
1. Gauge will not switch on.
Check batteries for corrosion, clean terminals,
replace batteries.
Check without batteries, with charger plugged
in. If this rectifies the problem, then remove
charger and fit new batteries.
Check battery charger output; should read
approximately 100mA constant current.
Check keypad functions, check with known
working keypad.
Check PCB for liquid ingress.
Replace PCB.
2. No display
Possible causes as above in ‘Gauge will not switch
on’.
Operator has changed contrast. Restore
contrast setting. (Software version dependent).
Display not configured/V1.12 or later firmware.
Check display ribbon cable connection.
Check with a known working LCD
Replace PCB.
3. Display behaves
unusually
If the LCD gives an unusual display the ribbon cable
may not have seated correctly in the header. Unclip
the ribbon cable, remove and reinsert into the header.
Re-secure and retest.
Check LCD ribbon cable connection.
See Section 10 Display Replacement.
Check with a known working LCD
Replace LCD.
4. OL shown on display
If OL is shown on the top left of the display, record
load cell offset. See section 5
If the recorded offset is below 5% should be okay.
Between 5 and 10%, take millivolt offset.
Above 10% possible replacement load cell.
If gauge beeps continuously and full load bar is
illuminated at the bottom of LCD. Record millivolt
offset. Load cell pins 2 + 3 should read ideally 0.0
mV.d.c. Highest acceptable limit is +/- 0.8 mV.d.c. If
above, replace load cell.
