"shell" digital storage oscilloscope (Beta) 1. Main board: solder the element as the picture shows: 2. 1) Check the main board is normal or not Supply 9V power supply through the connector J7 (Note: The connector center conductor is positive), the main control board to see whether the normal start, if the board is normal start, LCD screen will display the product model, software version, the oscilloscope's main working interface, as shown in Figure 2.
-Figure 2 If the LCD display is not normal, or the circuit board has significant heat, smoke and other phenomena, please immediately power off, recording and notification service vendors. 2) Assembly step After the MPU test normal, disconnect the power, then follow the steps below for assembly, first of all, soldering the backside element of LCD screen, then soldering the same side element of LCD screen. a. Soldering test signal output terminal J8, two feet bents 90 degrees, and then soldered to the board. b. Soldering backup power input J6. c. Soldering power supply switch SW5. d. At the same side of the screen soldering switches SW1, SW2, SW3 and SW4. E. Remove the resistor R30. R30 is a 0 ohm resistor, it is actually used for the power switch SW5 short-circuited, so that when the power switch SW5 is not yet installed can be energized to check, after the installation of SW5, R30 should be removed, so that SW5 can function properly. 3. Check the results of the assembly After the above installation steps, turn the power on, check whether the power switch is working properly, check 4 Press key is working properly. 4. Analog board assembly Analog board assembly sequence according to component height from low to high principle, specific assembly steps are as follows:
1) Resistance soldering. According to the resistance label material checklist printed on the PCB (see below) to find the appropriate resistor values, confirm the resistance with a multimeter; then bent the legs in the same direction, and the distance between the legs are about 8mm; soldering all ring resistances one by one. 2) Soldering ceramic capacitors C1, C2, C4, C6, C7. 3) Install a trimmer capacitor C3 and C5. 4) Install toggle switch SW1. 5) Install the electrolytic capacitors C10 - C14. 6) Install BNC connector J1. Note: Beta version's analog channels have a design error in which a wire missing, the need to manually fill, the method is to use a approximately 3cm short-wire connect R22 (near the BNC connector) with R24 (near the trimmer capacitor C5) Check as the FIG.3
5. Debugging FIG.3 Before power-on test, carefully check the soldering of all components as much as possible exclude the possibility of false soldering or short circuit, the circuit board and clean residual rosin solder, and then follow the steps below test debugging. 1) Set the POWER switch to the OFF position (ie, near the power outlet J7 position), then connect the power supply to the main circuit board J7 (or J6), switches the power switch SW5 to ON position, check the oscilloscope is normal start or not. If the screen displays normal, operates four buttons and rotary switch, check the reaction on the screen properly normal or not.
2) If the above tests are normal, then switches the power to the OFF position, then connects the double-pin J3 and row socket J4 on the main board, pay attention to the direction of the connection, as Figure 4 show: Figure 4. 3) Switches the power SW5 to ON position, watching the screen showed no abnormalities, if not then check the voltage, detecting point marked in the backside of the PCB, the normal value shown in the table: Test point label Normal voltage value Support Mix. Support Max. Specification AV+ 7.0V +5.5V +8.5V Input +9V AV- -6.5V -9.0V -5.0V Input +9V V5-1.0V -1.2V -0.8V 4) Put the coupling swith SW1 to GND, measure the following voltage: Normal voltage Test point label Support Mix. Support Max. Specification value V1 0V -0.1V +0.1V The coupling switch SW1 in
V2 0V -0.1V +0.1V the GND position V3 0V -0.1V +0.1V V4 +1.6V +1.3V +1.9V 6. Adjust the compensation capacitor C3 and C5 Adjustment C5: 1) Connect the probe and the BNC connector J1, and use the clip clamping the output terminal J8, black clip can be vacant (Fig. 5). 2) Set the scope parameter to the value shown in Fig. 5 screen, and adjust the trigger level to make the waveform stable. 3) Use a small screwdriver to adjust the C5, make the square wave-shaped angle is the best angle. Adjustment C3: FIG. 5 1) Between the test signal output terminal and ground connects a 20-30
ohm resistor (Figure 6), so that the test signal amplitude is reduced to approximately 0.1V (Note: This display value is only an approximation, the actual value is 0.1V - 0.2 V, does not affect the adjustment). 2) Set the oscilloscope parameter to the as shown in FIG. 7, and adjust the trigger level to make the waveform stable. 3) Use a small screwdriver to adjust the C5, make the square wave-shaped angle is the best angle. -----Commissioning is complete.