Through the repair of the HS4000 electronic governor circuit board from November 29 to December 2, the analysis is summarized for different faults. Through the analysis methods introduced in this document, the circuit board faults can be quickly located and resolved.
Two experimental equipment
DC power supply (24V, greater than 4A), ordinary oscilloscope, ordinary signal generator, computer with ACT software
Three instrument calibration
Voltmeter, oscilloscope calibration through the measurement of the standard voltage, and oscilloscope zero calibration before use.
Four Precautions
1. Troubleshooting should be done in strict accordance with the troubleshooting steps.
2. Measurement of the crystal with the X10 gear, to avoid affecting the work of the crystal.
3. If the measured value is not normal, the meter should be calibrated and tested again.
4. If a device is judged to be a problem, first of all, it should be re-tinned, and then replaced if the problem cannot be solved.
5. The troubleshooting methods appearing in this document can only be applied if specific conditions are met.
5 Troubleshooting Steps
[if !supportLists]1.[endif]Appearance Check
Compared to the sample focus on checking the leakage of soldering, short circuits, scratches, the base of the pins and pins are bent.
[if !supportLists]2.[endif]Static Inspection
Measure the input impedance to see if it is normal, and refer to the test standard.
[if !supportLists]3.[endif]Power-on check without CPU installed
Check whether the power supply and reset are normal, and refer to 7.1 to 7.3 to solve the problem if any.
[if !supportLists]4.[endif]Installation of CPU power check
In this check, the possible problems are controller can not be connected to the computer, the indicator does not light up, the controller has no output, the Actuator_fdbk_sense parameter is abnormal, and the solutions are shown in 6.4 to 6.8 respectively.
Six different failure solutions
[if !supportLists]1.[endif]Power supply failure
Experimental conditions: power supply 24V, no CPU installed.
Scope of application: circuit boards that have already passed the appearance check and static check.
Judgment criteria: 24V and 5V nodes are not normal
Failure analysis: Generally a problem with TIP41C
Solution: Re-solder or replace TIP41C.
[if !supportLists]2. [endif]Reset Voltage Failure
Experimental conditions: Power supply 24V.
Scope: The ground impedance of the MCU reset node on a board that has passed the appearance check and static check is about 10KΩ.
The test can be performed on a single chip, or on a single board with a single chip, or on a single chip with a single chip.
Judgment criteria: Power on the MCU reset node is not high.
Failure analysis: the level of the reset node depends on the output voltage of the LM2901, so you should check whether the device is working properly.
Solution: Check whether the LM2901 soldering, power, ground, input signal is normal. If all normal but the output is still not high level then replace the LM2901. if the input signal is not normal then refer to 6.3 to solve.
[if !supportLists]3.[endif]LM2901 Input Signal Failure
Experimental conditions: power supply 24V, no CPU installed.
Scope: has passed the appearance of the inspection and static check on the board.
Judgment criteria: LM2901 input signal is not normal.
Failure analysis: LM2901 input signal depends on the undervoltage protection circuit, so it should be the undervoltage protection circuit.
Solution: Generally LM4040BIM3-2.5 problem, re-weld or replace the device.
[if !supportLists]4.[endif]The controller can not be connected to the computer
Experimental conditions: power supply 24V, the output of a fixed duty cycle: 94%, and the addition of a resistive load.
Scope of application: Boards that have passed a visual inspection, static inspection, and no CPU power check, and have no problems with connectivity and software versions.
Judgment criteria: ACT software can not recognize the controller
Failure analysis: It is possible that the microcontroller is damaged, the microcontroller is not working properly or there are problems with the communication circuit.
Solution: Replace the normal function of the microcontroller, and check whether the vibration, if not vibration, then check the crystal oscillation circuit. If it does not, check the crystal circuit. If it does, the problem is likely to be the serial communication circuit, refer to 6.5 to solve the problem.
5. Serial communication circuit failure Experimental conditions: power supply 24V, not installed CPU.
Scope: has passed the appearance of the board and static inspection.
Judgment criteria: 24V and 5V nodes are not normal
Failure analysis: generally a problem with the TIP41C
Solution: Resolder or replace the TIP41C.
[if !supportLists]5. [endif]Indicator does not light up
Experimental conditions: Power supply 24V. The output fixed duty cycle is 94%, and a resistive load is added.
Scope: The board has passed the appearance check and static check.
Judgment criteria: 24V and 5V node is not normal
Failure analysis: generally for the TIP41C problem
Solution: re-soldering or replacement of the TIP41C.
[if !supportLists]6.[endif]Controller no output
[if ! supportLists]7.[endif]Actuator_fdbk_sense parameter abnormality
[if !supportLists]1.[endif]Actuator_fdbk_sense parameter abnormality Failure reason analysis:
1.1 BTS640S2 damage
Applicable conditions: BTS640S2 power supply, ground, input signals, output signals, diagnostic feedback signals are normal, IS pin to ground impedance of 2.2K and the power supply output current of about 3A.
Judgment criteria: If the BTS640S2 IS pin feedback can not be output feedback voltage, then it means that the BTS640S2 feedback function is not normal, BTS640S2 failure. BTS640S2 fault.
Solution: Re-solder the BTS640S2 pins to ensure that the failure is not caused by soldering, and if the problem still can not be solved, then replace the BTS640S2.
1.2 Microcontroller contact failure
Applicable conditions: MC145053D analog input is normal.
Judgment criteria: If the MC145053D analog input is normal, it is likely to be caused by poor microcontroller contact.
Solution: Test the base, make sure there is no glue and other debris on the base and replace the MCU.
Other causes: If still can not solve the problem, then it is likely to be the problem of MC145053D. The solution is shown in 1.3
1.3?MC145053D Damage
Applicable conditions: MC145053D analog input, SCLK, CS is normal, and the microcontroller is normal with no bad contact.
Solution: the MC145053D pins re-welded to ensure that it is not a fault caused by false soldering, such as still can not solve the problem is to replace the MC145053D.
[if !supportLists]2.[endif]Computer can not recognize the controller
2.1 Microcontroller reset failure
Experimental conditions:
Applicable conditions:
Judgment criteria: If the BTS640S2 IS pin feedback can not output feedback voltage, then it means that the BTS640S2 feedback function is not normal, BTS640S2 failure.
Solution: Re-solder the BTS640S2 pins to ensure that the failure is not caused by soldering, if the problem still can not be solved, then replace the BTS640S2.
2.1 MCU Failure
2.3 Undervoltage Protection Circuit Failure
2.4 MCU Crystal Failure
2.4 Communication Circuit Failure
[if !supportLists]3.[endif]Indicator light is damaged
3.1 Indicator pad is damaged
3.2 Indicator light is burnt out
[if !supportLists]4.[endif]Power supply is not normal
5. Actuator output is not normal