How to Use FNIRSI DSO-152 Plus for Electronics Troubleshooting Malaysia
How to Use FNIRSI DSO-152 Plus for Electronics Troubleshooting Malaysia
When an electronic device stops working, a digital multimeter is usually the first instrument technicians use.
But what happens when the power supply voltage looks normal and the circuit still does not operate correctly?
This is where a mini digital oscilloscope such as the FNIRSI DSO-152 Plus can become useful.
An oscilloscope allows you to see whether a signal is actually present and how that signal changes over time.
For basic electronics troubleshooting, this can help answer an important question:
Is the circuit receiving voltage but failing to produce the expected signal?
1. Start with the Power Supply
Before checking signal waveforms, confirm that the circuit has the correct power supply.
A digital multimeter is normally the easiest tool for this step.
Check the relevant supply rails, for example:
5 V
3.3 V
12 V
or whatever voltage is specified for the circuit.
If the supply voltage is missing, troubleshoot the power section first.
If the voltage is present but the circuit still does not operate correctly, you can proceed to waveform checking.
2. Check Whether a Signal Is Present
One of the simplest uses of the FNIRSI DSO-152 Plus is checking whether there is signal activity at a test point.
Suppose a circuit should generate a repetitive waveform.
The oscilloscope can help determine whether you have:
A visible waveform
A constant DC level
An unstable signal
No signal
This immediately gives the technician more information than a simple voltage reading.
3. Check Oscillator Circuits
Many electronic circuits depend on some form of oscillator or clock source.
If that signal disappears, other parts of the circuit may stop operating even though the power supply remains normal.
A mini oscilloscope can be useful for checking suitable low-frequency oscillator signals within the instrument's measurement capability.
You can compare:
Expected signal present
versus
No waveform detected
This can help narrow down the troubleshooting area.
4. Check Pulse Signals
Pulse signals are common in electronic equipment.
For example, a control circuit may produce pulses to operate another part of the system.
A multimeter may show some voltage at the test point without clearly showing what is happening.
With an oscilloscope, you can visually check whether pulses are being produced.
You can then investigate characteristics such as:
Frequency
Amplitude
Period
Waveform stability
Presence or absence of pulses
This is especially useful when troubleshooting basic digital and control circuits.
5. Compare Input and Output Signals
Another useful troubleshooting technique is to follow the signal through different stages of a circuit.
For example:
Input signal → processing stage → output signal
If the waveform is present at the input but disappears after a particular circuit stage, you have identified an area that deserves further investigation.
This does not automatically mean that one specific component has failed.
However, it helps reduce the troubleshooting area.
Instead of randomly replacing components, technicians can investigate the circuit more systematically.
6. Look for an Unstable Waveform
Not every electronic failure results in a completely missing signal.
Sometimes the waveform is present but unstable.
You may observe behaviour such as:
Changing amplitude
Irregular pulses
Unstable frequency
Unexpected waveform shape
Signal appearing and disappearing
These observations can provide useful clues during troubleshooting.
However, always consider the bandwidth, sampling and other limitations of the oscilloscope before interpreting what you see.
7. Compare a Working Circuit with a Faulty Circuit
If you have two identical electronic boards, waveform comparison can be particularly useful.
For example:
Board A = Working
Board B = Faulty
Measure the same test points on both boards under comparable conditions.
If one test point produces a normal waveform on Board A but a very different result on Board B, you have a useful troubleshooting lead.
This method is often easier than trying to determine every expected waveform from scratch.
8. Use the Trigger Correctly
A waveform that continuously moves across the display can be difficult to inspect.
The trigger function helps stabilise repetitive signals on the screen.
For beginners, learning basic triggering is one of the most important steps when learning to use an oscilloscope.
If the waveform appears unstable on the display, do not immediately assume the circuit is faulty.
First check whether the oscilloscope settings are appropriate.
The issue may simply be related to:
Trigger settings
Time base
Voltage scale
Probe setting
Signal connection
Correct setup is essential before drawing conclusions from a waveform.
9. Check the Probe Setting
Probe configuration is another important point.
If the oscilloscope and probe attenuation settings do not correspond correctly, the displayed voltage can be misleading.
Before measurement, confirm the probe configuration and make sure the oscilloscope is set accordingly.
This is especially important for beginners who may see a waveform and immediately assume the displayed amplitude is correct.
Always verify the measurement setup first.
10. Do Not Exceed the Instrument Limits
A small oscilloscope should never be connected to a circuit simply because the probe physically fits.
Before connecting the DSO-152 Plus, determine:
Expected voltage
Signal frequency
Circuit reference
Probe rating
Oscilloscope input limits
Measurement environment
If you are uncertain about the voltage or measurement method, do not connect the instrument until the application has been properly evaluated.
This is particularly important when working around mains electricity, high-voltage power electronics or other hazardous circuits.
Example Troubleshooting Workflow
A basic electronics troubleshooting sequence could look like this:
Step 1: Check the power supply with a multimeter.
Step 2: Identify the relevant signal test points.
Step 3: Connect the oscilloscope using the appropriate measurement method.
Step 4: Adjust the voltage and time settings so the waveform is visible.
Step 5: Stabilise the waveform using the trigger.
Step 6: Check whether the expected signal is present.
Step 7: Follow the signal through the circuit.
Step 8: Compare suspicious waveforms with the circuit documentation or a known-good board when available.
This approach can be more effective than replacing components without first understanding where the signal disappears.
Is the DSO-152 Plus Suitable for Professional Repair?
It depends on the application.
The FNIRSI DSO-152 Plus is better suited to basic waveform checking, learning and lower-frequency electronics troubleshooting than demanding professional oscilloscope applications.
A technician working with higher-frequency electronics, multiple signals simultaneously or advanced circuit analysis may require a higher-performance oscilloscope.
The key is to match the oscilloscope to the signals being measured.
DSO-152 Plus for Electronics Repair in Malaysia
For Malaysian technicians, students and electronics hobbyists who want a compact instrument for basic waveform troubleshooting, the FNIRSI DSO-152 Plus Mini Digital Oscilloscope can be a useful addition alongside a digital multimeter.
Instead of asking only:
“Is there voltage?”
you can start asking:
“Is the correct signal actually present?”
That is where an oscilloscope becomes valuable.
MTM Precision supplies FNIRSI electronic test and measurement instruments in Malaysia.
If you are unsure whether the DSO-152 Plus is suitable for the circuit or equipment you need to troubleshoot, send us a photo and brief description of your application through WhatsApp.
MTM Precision Sdn Bhd
Showroom & Service Centre:
No. 29-1 & 2, Jalan Bandar 18,
Pusat Bandar Puchong,
47160 Puchong, Selangor, Malaysia.
Tel: 03-8080 7172
WhatsApp: +6016-660 7346
Email: mtmpre@yahoo.com
Website: www.mtmpre.com.my
Supplying test and measurement instruments throughout Selangor, Kuala Lumpur, Johor, Penang, Melaka, Negeri Sembilan, Perak, Pahang, Kelantan, Terengganu, Kedah, Perlis, Sabah and Sarawak.
06 Oct 2026
