¶ Phenomenon:
1. The fill light is dim and cannot be turned off;
2. The brightness of the LED fill light is normal but cannot be turned off;
3. The LED fill light is only partially turned on, and the control is normal;
4. The AP restarts and the display screen reproduces the boot screen;
5. The screen is black after powering on the printer, and the AP start-up fails, but the indicator on the MC board is normal.
¶ Causes & Solutions
1. A modification has caused the LED driver on the AP board to burn out, and need replace the AP board and the fill light cable (or the entire fill light assembly);
2. The fill light cable is damaged and short-circuited, the LED fill light cable (or the entire fill light assembly) needs to be replaced;
3. Part of the lamp beads of the fill light is burnt out, and the LED fill light needs to be replaced;
4. The 5V power supply IC on the AP board is burnt out, and the AP board and the fill light cable (or the entire fill light assembly) need to be replaced.
¶ Safety warning and Machine state before starting operation
When disassembling and assembling, it is necessary to confirm that the printer is powered OFF.
¶ Tools needed
- H2.0 hex key
- Tweezers
- Multimeter
¶ Troubleshooting
¶ 1. The LED fill light is dim and cannot be turned off
The LED fill light circuit supports up to 5V 0.3A fill light, so a short circuit or overcurrent may cause damage to the AP board. You can use a multimeter to measure the voltage at the connector of the supplementary light to determine whether the AP board has been burnt.
Troubleshooting: When the printer is turned on, use a multimeter to measure the voltage between the pin of the black cable and the printer side panel. If the voltage is greater than 1V and the LED is dim, the LED drive circuit of the AP board is burnt out. In this case, the risk of a short circuit is high. It is recommended to replace the AP main board and the fill light cable together.
If you do not have a multimeter, it is also a priority to replace the AP main board and the fill light cable.
¶ 2. The LED fill light is always on in normal brightness
The LED fill light cable wears easily during the assembly process. If the black wire is worn out and is short-circuited with the side panel, the fill light cannot be turned off. In this case, if you shake the cable of the fill light, the function of the fill light will be restored.
Troubleshooting: Power off the printer, and use a multimeter to measure the continuity between the black cable and the printer side panel. If it is conductive, it means that there is a short circuit and the LED fill light cable needs to be replaced.
¶ 3. The LED fill light is only partially lit
Only some of the beads of the LED fill light are on with normal brightness. This means that the unlit lamp bead is burnt out, and the LED fill light needs to be replaced.
¶ 4. AP restarts and the display screen the boot screen is on a loop
When the printer is turned on or the printer is in a working state, the AP powers off and restarts and the boot screen is seen repeatedly. In this case, the red cable of the LED fill light is short-circuited with the side panel.
Troubleshooting: Disconnect the fill light cable and start printing. If the printer returns to normal, it means that the fill light cable needs to be replaced. It is also possible to use a multimeter to test the conductivity between the red cable of the fill light and the printer side cover when the printer is off.
¶ 5. After power on, the LED is off, the display screen is black, and the AP is not started
The power indicator (steady on) on the AP main board is normal, but the working status indicator is not on.
Troubleshooting: You can check whether the 5V power supply IC is burnt. Generally, there will be a mark after burning. If the 5V IC is burnt out, the AP board and the fill light need to be replaced.
If the 5V power supply IC is not burnt, you only need to replace the AP main board.
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