Injection molding machine computer common fault diagnosis and troubleshooting alarm information caus
Time：2025-06-26 08:06:32 / Popularity： / Source：
Common fault diagnosis and troubleshooting of injection molding machine computer
Common fault diagnosis process
Common troubleshooting methods
| Alarm information | Causes and troubleshooting methods |
| No display and no backlight | 1. Is connection line loose? Tighten connection line screws; 2. Power problem, check whether power supply of power supply box is normal; 3. Is display panel light on; 4. Is output voltage of 7805 voltage regulator tube on the back cover of panel 5V; 5. Is 7805 voltage regulator tube on the back cover of panel properly plugged in; |
| Backlight but no words | 1. Is connection line loose? Tighten connection line screws; 2. Power problem, check whether power supply of power supply box is normal; 3. Is contrast adjusted? Adjust contrast; 4. Are two indicator lights (A2, A3) on the back of panel on? 5. If A2 indicator light is on and A3 indicator light is not on, check whether program is plugged in; 6. Is connection between LCD module and display board properly plugged in: |
| Words but no backlight | 1. Is connection line loose? Tighten connection line screws, 2. Check power supply +12V , is +24V1A normal; 3. Is connection line (20, 26 core wire) between display board and keyboard board connected well; 4. Is backlight of LCD module plugged in well; |
| Display flashes | 1. Is connection line loose? Tighten connection line screw; 2. Power problem, check whether power supply of power box is normal; 3. Check whether voltage regulator tube 7805 on back cover of panel is plugged in well and whether output voltage is normal; 4. Is peripheral power supply voltage (220VAC or 380VAC) too low or unstable; |
| Data loss | 1. Low battery voltage (generally not less than 3V); 2. Bad memory block; 3. Check whether model page setting is normal (0 model is not memorized); 4. Change between Chinese and English, change display program; |
| Not started | 1. Power problem, whether power supply +5V, +24V1A, +24V6A voltage is normal, and whether red light of motherboard is on; 2. Is emergency stop switch pressed and RUN light is on? If not, short-circuit directly RUN and COM; 3. Is there a short circuit? Is short circuit protection indicator light (a red light near CPU) on? If it is on, first check whether power supply +24V6A is normal, disconnect load (that is, do not connect hydraulic valve), restart, if it starts normally, then check whether peripheral load has a short circuit; 4. Is program plugged in properly or not; |
| Motor jumps | 1. Is there an alarm: 2. Is there a short circuit or overload; 3. Is three-phase power normal; 4. Is connection between display board and lower keyboard in panel loose; |
| No action | 1. Is RUN light on? Is panel manual light on? 2. Check whether power supply +24V1A, +24V6A, +36V4A is normal, and whether fuse is burned? 3. Is data set? 4. Check whether there is no pressure flow or no directional valve output; 5. Is travel switch pressed (is indicator light on), check whether travel switch is short-circuited or travel switch is improperly positioned; 6. Is there any output? If there is output, check whether peripheral hydraulic valve is broken or disconnected; |
| No output | 1. Is output indicator light on? Disconnect load first to see if indicator light is on. Use a multimeter to measure whether there is a 24V voltage at output end. If there is no voltage, check whether output transistor is broken. If there is voltage, check whether peripheral is broken or hydraulic valve is broken; 2. Is travel switch pressed (is indicator light on), check whether travel switch is short-circuited or travel switch is improperly positioned; |
| No input | 1. Check whether power supply +24V1A is normal; 2. First connect corresponding input point to 24VG Short-circuit and see if input indicator light is on. If it is on, check if wire of travel switch is broken or if travel switch is broken. If it is not on, check if input indicator light is broken; |
| Normal output | 1. Press emergency stop switch to see if output indicator light is still on. If it is on, output transistor is broken and corresponding transistor should be replaced; 2. Use a multimeter to measure whether there is a 24V voltage output at corresponding output terminal. If there is no output, hydraulic valve is broken; |
| Number of ejection pins is incorrect | 1. Is line from peripheral to host input point X014, X013 loose? 2. Is stroke switch loose? 3. Is stroke switch damaged? |
| Flow pressure is always output | 1. Display monitoring page to see if there is flow pressure data display. If there is display, change program; 2. Press emergency stop switch to see if there is still output. If there is no output, host board is broken; 3. Is output transistor C and E short-circuited? If short-circuited, replace transistor; |
| Flow pressure has no output | 1. Is power box +36V4A normal? Is fuse burned? 2. Disconnect valve, press an action, and use a multimeter to measure whether there is output voltage. If there is no output voltage, check whether feedback resistor (5W1Ω) is open; if there is output voltage, use a multimeter to measure whether valve resistance is normal; |
| No electronic ruler stroke | 1. Is the total stroke of electronic ruler set? Is zeroing switch set to "on" ("on" means data is always zero); 2. Check power supply Are +12V and -12V voltages normal? 3. Use a multimeter to measure whether voltage at both ends of electronic ruler is 10V. If not, check electronic ruler. 4. Is ruler board properly plugged in or broken? 5. Is line of electronic ruler connected incorrectly? 6. Is electronic ruler broken? |
| Electronic ruler stroke is inaccurate | 1. Is electronic ruler reset position correct? It should be reset at initial position of each stroke; 2. Is electronic ruler wire connected incorrectly? 3. Is electronic ruler broken? 4. If there is no such problem, electronic ruler board must be adjusted. This must be adjusted by professionals. |
| Temperature 999 | 1. Check whether 44-core wire between thermocouple wiring board and main board is loose; 2. Is thermocouple in poor contact or broken? 3. Replace thermocouple wiring board or main board; |
| Temperature 99 or 101 | 1. Check whether power supply +12V, -12V is normal 2. Transistor 335 of thermocouple wiring board or transistor 336, C351 of main board is broken; |
| Temperature is chaotic (or floating) | 1. Check power supply +12V, -12V Is it normal? 2. Is 44-core wire plugged in properly: Is thermocouple wire in good contact or broken? 3. Is connection from thermocouple to adapter board shielded? 4. Is thermocouple terminal board grounded? 5. If there is no problem, replace motherboard; |
| No heating |
1. Are data and function settings on temperature page correct? 2. Is power supply 24V1A voltage normal? 3. Is fuse burned out? 4. Is heating indicator light on? If not, check whether indicator light, relay, and resistor are broken? 5. Is contactor energized? Is corresponding air switch tripped? Is heating coil broken? |
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