The online tester, as the name implies, is a tool used for testing and repairing PCBA boards. It is capable of performing both online and offline functional tests on small to medium-sized digital integrated circuits, memory chips, and some large-scale integrated circuit chips. Additionally, it can measure the V-I curve at any point on the PCB.
**Main Functions of the Online Tester**
1. **Functional Test**
The functional test, abbreviated as ICFT, refers to the process where the online tester uses the post-drive principle to activate the circuit and then performs a comparative analysis to derive the result. The post-drive principle involves altering the circuit behavior according to the tester’s control, adjusting the input levels to either higher or lower values. This effectively “isolates” the gate under test from the surrounding circuit, allowing the tester to verify whether the input and output meet the required logical relationship. This method is used to complete the logic function test of the circuit chip.
2. **Curve Test**
**Curve Test**
Curve testing refers to the VI curve test, which helps identify fault points by comparing the forms of the curves. Initially, test two nodes on a functioning PCB to obtain the voltage (V)-current (I) relationship curve, and save the results as a baseline for future comparisons. When a similar PCB board fails, use the online tester to perform a VI test on any two nodes of the faulty board, and simultaneously retrieve the corresponding VI curve from the working PCB for comparison. If the comparison results fall outside the normal range, the two nodes in question are likely to be fault points.
**3. Memory Test**
For random access memory (RAM), use the write/read method to test. First, write a piece of data to the memory cell, then read it back to check if the two values match. If they differ, the memory is faulty. For read-only memory (ROM), read the stored content from the memory unit and save it to the computer. In future tests, compare it with the data read from the corresponding memory unit on the faulty PCB. If the content matches, the memory is likely functioning correctly.
**4. Status Test**
This test involves checking the logic level of each pin on the device and comparing it with that of a known good device to determine functionality.
**5. Custom Test**
The online tester also offers a digital circuit functional test platform, where users can define the input pin excitation and describe the logical relationship between the device’s inputs and outputs. If the logical relationship is satisfied, the device is functioning properly.
### **Application of the Online Tester in PCB Repair**
**1. Preparation Before Maintenance**
If the components on the PCB are not labeled, create a diagram marking the component locations and numbers. This diagram will serve as a reference during testing.
Additionally, create a comparison library. This is a crucial task before using the online tester for PCB repair. The library contains the test results of the component pin status, VI curve waveforms, and ROM data from a working PCB, which can be used for comparison and analysis when diagnosing the faulty board.
**2. Repair Steps**
**Step 1: Visual Inspection**
When a PCB needs repair, begin by gathering information about the failure symptoms and carefully inspect the board for obvious issues such as burnt areas, blown fuses, loose connectors, or disconnected traces.
**Step 2: Power Supply Testing**
Use a multimeter to check the working power supply for any short circuits in the PCB components.
**Step 3: Offline Testing**
Remove pluggable components from the board and perform offline testing to isolate potential issues.
**Step 4: Online Testing**
Test the remaining components on the board to identify the failure point.
**Step 5: Trial Run**
Once the fault point is located and repaired, conduct an online test to verify that the fault has been completely resolved. If the issue persists, repeat the diagnostic steps to identify the fault.
**Step 6: Record Keeping**
During the testing process (including building the comparison library), it’s important to keep detailed records, especially for any suspicious findings. Document the symptoms observed during testing for future reference.
If you have any PCB manufacturing needs, please do not hesitate to contact me.Contact me
**Main Functions of the Online Tester**
1. **Functional Test**
The functional test, abbreviated as ICFT, refers to the process where the online tester uses the post-drive principle to activate the circuit and then performs a comparative analysis to derive the result. The post-drive principle involves altering the circuit behavior according to the tester’s control, adjusting the input levels to either higher or lower values. This effectively “isolates” the gate under test from the surrounding circuit, allowing the tester to verify whether the input and output meet the required logical relationship. This method is used to complete the logic function test of the circuit chip.
2. **Curve Test**
**Curve Test**
Curve testing refers to the VI curve test, which helps identify fault points by comparing the forms of the curves. Initially, test two nodes on a functioning PCB to obtain the voltage (V)-current (I) relationship curve, and save the results as a baseline for future comparisons. When a similar PCB board fails, use the online tester to perform a VI test on any two nodes of the faulty board, and simultaneously retrieve the corresponding VI curve from the working PCB for comparison. If the comparison results fall outside the normal range, the two nodes in question are likely to be fault points.
**3. Memory Test**
For random access memory (RAM), use the write/read method to test. First, write a piece of data to the memory cell, then read it back to check if the two values match. If they differ, the memory is faulty. For read-only memory (ROM), read the stored content from the memory unit and save it to the computer. In future tests, compare it with the data read from the corresponding memory unit on the faulty PCB. If the content matches, the memory is likely functioning correctly.
**4. Status Test**
This test involves checking the logic level of each pin on the device and comparing it with that of a known good device to determine functionality.
**5. Custom Test**
The online tester also offers a digital circuit functional test platform, where users can define the input pin excitation and describe the logical relationship between the device’s inputs and outputs. If the logical relationship is satisfied, the device is functioning properly.
### **Application of the Online Tester in PCB Repair**
**1. Preparation Before Maintenance**
If the components on the PCB are not labeled, create a diagram marking the component locations and numbers. This diagram will serve as a reference during testing.
Additionally, create a comparison library. This is a crucial task before using the online tester for PCB repair. The library contains the test results of the component pin status, VI curve waveforms, and ROM data from a working PCB, which can be used for comparison and analysis when diagnosing the faulty board.
**2. Repair Steps**
**Step 1: Visual Inspection**
When a PCB needs repair, begin by gathering information about the failure symptoms and carefully inspect the board for obvious issues such as burnt areas, blown fuses, loose connectors, or disconnected traces.
**Step 2: Power Supply Testing**
Use a multimeter to check the working power supply for any short circuits in the PCB components.
**Step 3: Offline Testing**
Remove pluggable components from the board and perform offline testing to isolate potential issues.
**Step 4: Online Testing**
Test the remaining components on the board to identify the failure point.
**Step 5: Trial Run**
Once the fault point is located and repaired, conduct an online test to verify that the fault has been completely resolved. If the issue persists, repeat the diagnostic steps to identify the fault.
**Step 6: Record Keeping**
During the testing process (including building the comparison library), it’s important to keep detailed records, especially for any suspicious findings. Document the symptoms observed during testing for future reference.
If you have any PCB manufacturing needs, please do not hesitate to contact me.Contact me
