Friday, May 27, 2016

Tektronix DPO2000 - MSO2000 Oscilloscopes – Mixed signal oscilloscope – Factory adjustment procedure – How to calibrate the DC voltage and sine wave signal – Main board parts description – Exploded view – test and measurement equipment repair and service

Category: Test and Measurement Equipment Repair and Service 

Contents of this article

  • Factory adjustment procedure 
  • DC and sine wave signal calibration 
  • Mainboard parts and expoled view

Tektronix DPO2000 - MSO2000 Oscilloscopes

Factory Adjustment Procedure
To perform the factory adjustment procedure, complete these steps:
1. Connect the oscilloscope to an AC power source.
NOTE: You must connect the oscilloscope and the test equipment to the same AC power circuit. Connect the oscilloscope and test instruments to a common power strip if you are unsure of the AC power circuit distribution. Connecting the oscilloscope and test instruments to separate AC power circuits can result in offset voltages between the equipment, which can invalidate the adjustment procedure.
2. Power on the oscilloscope and warm it up for 20 minutes.
3. Power on the oscilloscope calibrator and warm it up for 20 minutes.
4. Connect the active heads from the calibrator to the oscilloscope, ensuring that Channel 1 on the calibrator connects to Channel 1 on the oscilloscope, and so on.
NOTE: For the DPO2000, there will be either 2 or 4 channels to connect. For the MSO2000, there will be either 2 or 4 channels to connect, plus an additional channel connection for the digital probe. Plug the digital probe into the Channel
5 active head on the calibrator, using the BNC to square pin adapter, but do not plug the probe into the oscilloscope until you are directed to by the calibration process. Once you do plug the digital probe into the oscilloscope, do not unplug it until the adjustment procedure is completed.
5. Access the Factory Adjustment menu:
a. Press the front-panel Utility button, and then press the bottom-bezel Utility Page button.
b. Use Multipurpose knob a to select Calibration, and then press the bottom-bezel Factory button. The Factory adjustment passed dialog will appear.
c. While the dialog window is open, press and hold the top side-bezel button (below the Waveform Only button) for approximately five seconds. The Factory Adjustment description and menu will appear.
d. Push the OK Do Factory Adjustment side-bezel button to start the adjustment process. Prompts appear on the oscilloscope screen to indicate the signal type and the channels to which it should be connected.
NOTE: The oscilloscope adjusts itself automatically using the calibrator signal as a reference. You do not need to make any adjustments.
If you make an error, such as connecting the wrong input signal, you can repeat the last step by pushing the Return to Previous Screen side bezel button.
6. For each step, refer to the following table to identify the signal type.
Signal type
Example prompt
Parameters to set
DC Voltage

Apply 0 V DC 50 Ω termination signal to 3.
Waveform type, voltage, termination, channel

Sine Signal

Apply 2.0 V Pk-Pk 1 MHz 50 Ω termination sine signal to 3.

Waveform type, voltage, frequency, termination, channel
7. Continue with the adjustment process until it is complete and you receive the Pass notification. You can cancel the process at any time by pushing the MENU OFF button.
8. Complete the performance verification tests to verify that the adjustment procedure has correctly calibrated the oscilloscope.
Completing the Procedure
Instructions for completing the DC Voltage, Deskew, and Sine Signal tests are below. For each step in the calibration procedure, start at the beginning of the numbered instructions for the specific test type, and carefully complete each step. If the oscilloscope fails a step, consult the Troubleshooting section at the end of this chapter, revert to the previous step and try again. If the step fails again, return to the first step in the calibration procedure and try the entire procedure again. If the procedure fails, there could be problem with the oscilloscope.
DC Voltage
The DC Voltage test is the first test to appear on the prompts, and it usually makes up the majority of the calibration procedure tests. For each DC Voltage test, complete all 8 steps listed below to best ensure that the test will pass.
1. Push the DC/Square button.
2. Push the WAVEFORM lower-bezel button, and then push the DC Positive right-bezel button.
3. Push the CHANNEL SELECT lower-bezel button.
4. Push the LOAD lower-bezel button to highlight either 1M Ω or 50 M Ω .
5. EXIT lower bezel button.
6. If the amplitude field is not selected, use the front panel scroll buttons. Type the specified voltage, and then push the appropriate unit in the right-bezel menu.
For 0 V: ground the signal by pushing the grounding lower-bezel button. When this is active, you will not be able to make a channel selection, so in some cases you might need to temporarily deselect the grounding option while you make a channel selection. If the prompt requires all channels and the signal is grounded, The calibrator screen will default to Channel 1.
For any nonzero voltage: Before you select the voltage, you must first ensure that the calibrator is in direct mode. Push the lower-bezel button until 1.0 is selected.
7. Ensure that the red light is illuminated to indicate that the output is on. If not, push the ON button
8. On the oscilloscope, push the OK Do Next Step side-bezel button.
Sine Signal
When a Sine Signal prompt appears, complete the following steps:
1. Push the Sine front panel button.
2. To ensure that the voltage is in direct mode, push the lower-bezel button and select 1.0.
3. Push the CHANNEL SELECT lower-bezel button, and then ensure that Channel 5 is selected.
4. Ensure that the red light is illuminated to indicate that the output is on. If not, push the ON button.
5. On the oscilloscope, push the OK Do Next Step right-bezel button.
Main Board Parts
The Main board module contains the following functions:
Acquisition System
The Acquisition system begins by accepting the differential mode channel signals from the Front End assembly, which are routed to the A/D inputs, and ends with a digitized signal in memory.
Trigger System
The Trigger system processes the digitized signal stored in memory. Advanced trigger functions are enabled only when the appropriate application modules and supporting software are installed.
Display System
The Display system combines live waveform data from acquisition memory with menus and text, and stores this information in display memory. It then uses this data to refresh the WQVGA display module (LCD).
Processor System
The Processor system contains a Power PC microprocessor that controls the entire instrument. The processor system also contains FLASH ROM, system RAM, and interfaces to Ethernet and to the USB ports.
Front-Panel Board
The Front Panel board contains a microprocessor that reads the front-panel buttons and controls, and then sends this information to the processor system on the Main board. The Front Panel board also generates the probe compensation output signal and provides an interface to the application modules.
Locator for internal modules