FNIRSI FNAC-28 Complete USB Tester and Charging Troubleshooting Guide Malaysia

Introduction

USB charging technology is used in smartphones, tablets, power banks, portable electronics, computer accessories and many other electronic devices.

Although USB charging appears simple, actual electrical performance depends on several factors.

These include output voltage, charging current, electrical power, USB cable resistance, connector quality, fast-charging protocols and device compatibility.

A smartphone may charge slowly even when connected to a high-wattage charger.

A power bank may deliver less output charge in mAh than its advertised internal battery capacity.

A USB cable may allow conventional charging but fail to support a particular fast-charging mode.

Understanding these situations requires suitable electrical measurements and a systematic troubleshooting approach.

The FNIRSI FNAC-28 USB Tester is a compact instrument designed to measure electrical parameters in compatible USB charging systems.

It can assist with USB charger testing, power bank output monitoring, cable resistance comparisons and selected fast-charging protocol investigations.

This complete guide explains the FNIRSI FNAC-28, its measurement functions, practical applications, limitations and buying considerations for customers in Malaysia.

It also provides a structured reference for electronics technicians, repair workshops, retailers, students and technical users.

1. What Is FNIRSI FNAC-28?

The FNIRSI FNAC-28 is a USB digital tester designed for monitoring electrical parameters in compatible USB power connections.

It allows users to observe important electrical measurements such as:

• USB Voltage

• USB Current

• USB Power

• Charging Behaviour

• Supported USB Cable Resistance Measurements

• Selected Fast-Charging Protocol Functions

The instrument is useful for investigating common USB charging problems.

For example, a technician can use it to observe whether a smartphone is charging at approximately 5W, 10W or 18W under the current operating conditions.

However, the FNAC-28 is not a complete USB compliance analyser or a substitute for specialised electrical safety equipment.

Its main purpose is practical USB electrical measurement and preliminary troubleshooting.

2. FNIRSI FNAC-28 Technical Specifications

Important: The stated electrical measurement limits do not mean the instrument can negotiate every high-power USB-C charging mode.

Users should follow the manufacturer's instructions and verify the functions supported by their instrument version.

3. Understanding USB Voltage, Current and Power

Before using a USB tester, it is important to understand three basic electrical quantities.

USB Voltage

Voltage is measured in volts (V).

A conventional USB charging system commonly operates around 5V.

Compatible fast-charging systems may use higher voltages.

USB Current

Current is measured in amperes (A).

The amount of current depends on the connected device, charging method and available power source capability.

USB Power

Power is measured in watts (W).

The formula is:

Power (W) = Voltage (V) x Current (A)

Practical Examples

These are mathematical examples, not a list of charging modes that the FNAC-28 can independently activate.

A charger rated at 65W does not necessarily deliver 65W to every connected device.

Actual charging power depends on compatibility and device demand.

4. How to Test a USB Charger with FNIRSI FNAC-28

USB charger testing is one of the main applications of the FNIRSI FNAC-28.

Step 1 - Check the Charger Specifications

Read the manufacturer's stated output voltage, current and charging protocols.

Step 2 - Inspect the Equipment

Check the charger, USB cable and connectors for visible damage.

Step 3 - Connect the USB Tester

Install the FNIRSI FNAC-28 using a compatible connection arrangement.

Step 4 - Connect a Suitable Load

Use a compatible device or a suitable electronic load.

Step 5 - Observe the Measurements

Record:

• Voltage

• Current

• Power

• Changes During Operation

Step 6 - Compare with Specifications

Evaluate the readings against the charger's applicable output specifications and operating conditions.

Step 7 - Repeat if Necessary

Compare the charger with known-good equipment.

A single charging measurement should not be treated as a complete charger performance certification.

5. How to Troubleshoot Slow Smartphone Charging

Slow charging is a common complaint among smartphone users.

Possible causes include:

• Insufficient Charger Output Power

• Charging Protocol Incompatibility

• High USB Cable Resistance

• Damaged Connectors

• Battery Nearly Fully Charged

• High Device Temperature

• Device Charging Restrictions

Practical Example

A smartphone is connected to a charger advertised as 30W.

The FNIRSI FNAC-28 displays:

Voltage: 5.0V

Current: 1.5A

Calculated power:

5.0V x 1.5A = 7.5W

This means the measured charging power at that moment is approximately 7.5W.

It does not automatically mean that the charger is faulty.

The smartphone may be limiting current because of battery temperature, battery charge level or charging compatibility.

Recommended Troubleshooting

1. Check the charger rating.

2. Check the smartphone charging requirements.

3. Inspect the USB cable.

4. Measure voltage and current.

5. Compare with a known-good charger.

6. Compare with a known-good cable.

7. Investigate protocol compatibility if necessary.

A systematic comparison is more reliable than replacing the charger immediately.

6. USB Cable Resistance Testing

USB cables contain conductors and connectors that introduce electrical resistance.

When current flows, this resistance produces voltage drop.

The relationship is:

Voltage Drop (V) = Current (A) x Resistance (Ohm)

For example:

Current: 2A

Resistance: 0.15 ohm

Calculated voltage drop:

2A x 0.15 ohm = 0.30V

Higher resistance can contribute to lower voltage at the connected device.

Factors Affecting USB Cable Performance

• Cable Length

• Conductor Size

• Conductor Material

• Connector Contact Resistance

• Cable Construction

• Current Rating

The FNIRSI FNAC-28 provides a supported cable resistance testing function.

However, a resistance reading alone does not establish full USB cable compliance.

Low cable resistance does not guarantee USB PD compatibility, high-speed data performance or correct E-Marker characteristics.

7. USB-A vs USB-C Charging

USB-A and USB-C are different connector types.

However, connector type alone does not determine maximum charging power.

USB-A

USB-A is widely used in conventional USB charging systems and selected proprietary fast-charging arrangements.

USB-C

USB-C is commonly used in modern smartphones, tablets and laptops.

Compatible USB-C systems may support USB Power Delivery.

However, not every USB-C charger or device supports the same power delivery modes.

Comparison Table

USB-C does not automatically mean faster charging.

The complete charging system must be compatible.

8. Fast Charging Protocol Testing

Modern USB charging systems may use different fast-charging technologies.

Examples include:

• Qualcomm Quick Charge QC2.0

• Qualcomm Quick Charge QC3.0

• Samsung AFC

• Huawei FCP

• Huawei SCP

• Selected VOOC and Related Proprietary Systems

• USB Power Delivery

• USB PD PPS

The FNIRSI FNAC-28 provides selected non-PD fast-charging protocol testing functions.

Actual compatibility depends on the charger, protocol version and instrument specifications.

Important Limitation

The FNIRSI FNAC-28 does not support:

USB PD Active Triggering

USB PD Packet Capture

For detailed USB Power Delivery negotiation analysis, suitable dedicated equipment is required.

Do not use unsupported voltage triggering with incompatible or unprotected loads.

9. Why Does Fast Charging Sometimes Fail?

Fast charging may fail even when both the charger and smartphone advertise fast-charging capabilities.

Possible reasons include:

Protocol Incompatibility

The charger and device may use different charging technologies.

Cable Limitations

The cable may not meet the required current rating or proprietary charging requirements.

Battery Temperature

The device may reduce charging power to control temperature.

Battery Charge Level

Charging current often decreases as the battery approaches full charge.

Charger Power Allocation

A multiport charger may reduce available power when additional devices are connected.

Device Charging Controls

The smartphone may limit power for battery management reasons.

Fast-charging performance depends on the charger, cable, connected device and operating conditions.

10. Power Bank Output Testing

Power banks store electrical energy in rechargeable batteries and provide regulated USB output power.

The FNIRSI FNAC-28 can assist with monitoring compatible power bank output conditions.

Useful measurements include:

• USB Output Voltage

• Output Current

• Instantaneous Power

• Changes During Discharge

• Output Behaviour Under Different Loads

Example

Measured voltage: 5.0V

Measured current: 2.0A

Calculated power:

5.0V x 2.0A = 10W

This indicates that the power bank is delivering approximately 10W at that measurement point.

However, it does not establish the power bank's total usable energy capacity.

A complete capacity evaluation requires suitable accumulated energy measurement and controlled discharge testing.

11. Power Bank Capacity vs Actual USB Output Energy

Power bank capacity is commonly advertised in mAh.

However, mAh describes electrical charge rather than energy.

Electrical energy is expressed in Wh.

The formula is:

Energy (Wh) = Capacity (Ah) x Nominal Voltage (V)

Example - 10000mAh Power Bank

Assume:

Battery capacity: 10000mAh

Nominal battery voltage: 3.7V

Nominal stored energy:

10Ah x 3.7V = 37Wh

If the hypothetical overall energy delivery ratio is 85%:

37Wh x 0.85 = 31.45Wh

Equivalent USB output charge at 5V:

31.45Wh / 5V = 6.29Ah

Therefore:

Estimated USB Output Charge = 6290mAh at 5V

This is an illustrative calculation.

Actual results vary with power bank design, battery condition, load and temperature.

A 10000mAh internal battery rating should not be compared directly with output mAh measured at 5V.

12. USB Charger vs Power Bank Comparison

USB wall chargers and power banks provide electrical power through USB connections, but their energy sources differ.

A suitable power bank may provide charging power comparable to a wall charger.

However, performance depends on the actual products.

Neither power source is automatically faster than the other.

13. USB Charging Voltage Drop Troubleshooting

Voltage drop is an important consideration when investigating slow or unstable charging.

Possible causes include:

• USB Cable Resistance

• Connector Resistance

• Charger Voltage Regulation

• Excessive Load Current

• Poor Electrical Contact

Example

Voltage near charger: 5.10V

Voltage near connected load: 4.85V

Calculated difference:

5.10V - 4.85V = 0.25V

The voltage drop between the two measurement points is 0.25V.

However, both readings must represent equivalent load conditions.

A single USB tester reading cannot independently determine the complete voltage drop across a cable.

Additional suitable measurement arrangements may be required.

14. USB Charger Load Testing

Load testing helps evaluate charger performance under controlled electrical conditions.

A simplified arrangement is:

USB Charger -> FNIRSI FNAC-28 -> Electronic Load

The FNIRSI FNAC-28 measures compatible USB electrical parameters.

The separate electronic load draws controlled current.

Illustrative Test Results

These are hypothetical measurements.

The results should be compared with the charger's applicable output specifications.

The FNIRSI FNAC-28 is not itself a programmable electronic load.

Never exceed the lowest applicable rating of the charger, tester, load or connecting accessories.

15. USB Charger Quality Evaluation

When selecting a USB charger, consider more than maximum advertised wattage.

Important factors include:

Electrical Specifications

Check supported output voltages, currents and power ratings.

Charging Compatibility

Confirm the charging protocols required by the intended device.

Output Performance

Evaluate electrical behaviour under suitable test conditions.

Construction Quality

Inspect the connector design, housing and product markings.

Safety Compliance

Check relevant safety documentation and applicable Malaysian regulatory requirements.

Manufacturer Support

Consider warranty, technical documentation and supplier reliability.

The FNIRSI FNAC-28 can assist with preliminary electrical performance observations.

However, it cannot verify electrical insulation, leakage current, electromagnetic compatibility or formal product safety certification.

Electrical output measurements are not a substitute for regulatory compliance testing.

16. Common USB Charging Problems and Solutions

This table provides preliminary guidance rather than a definitive fault diagnosis.

17. FNIRSI FNAC-28 vs Other Electronics Test Instruments

Different test instruments serve different purposes.

The FNIRSI FNAC-28 is most useful when investigating compatible USB charging systems.

It complements specialised test instruments rather than replacing them.

18. Applications of FNIRSI FNAC-28 in Malaysia

Mobile Phone Repair Shops

Investigate slow charging, cable problems and compatible charger performance.

Electronics Service Centres

Perform preliminary USB electrical measurements and troubleshooting.

Computer Accessories Retailers

Compare USB chargers, power banks and charging cables.

Power Bank Retailers

Explain output power and battery capacity differences to customers.

Electronics Training Centres

Demonstrate voltage, current, power and basic electrical calculations.

Universities and Polytechnics

Support suitable introductory USB measurement experiments.

TVET Institutions

Provide hands-on training involving low-voltage USB electrical measurements.

DIY Electronics Users

Investigate compatible USB-powered devices and charging accessories.

19. How to Choose the Right USB Tester

Before purchasing a USB tester, consider the intended application.

Measurement Range

Confirm that the voltage and current ranges are suitable.

Connector Compatibility

Check whether the instrument supports the required USB interfaces.

Charging Protocol Requirements

Determine whether selected QC, AFC or other protocol functions are sufficient.

USB PD Requirements

For detailed USB PD testing, choose equipment with appropriate PD analysis capabilities.

Cable Testing Requirements

Check whether the instrument provides suitable cable resistance measurement functions.

Ease of Use

Consider display readability and operating procedures.

Technical Support

Choose a supplier that can provide product information and suitable instrument recommendations.

The right USB tester depends on the measurements and charging technologies the user needs to investigate.

20. USB Charging Troubleshooting Checklist

Before replacing a USB charger, cable or power bank, follow a systematic procedure.

1. Check the Power Source Specifications.

2. Inspect USB Cables and Connectors.

3. Confirm Device Charging Compatibility.

4. Measure USB Voltage.

5. Measure Charging Current.

6. Calculate or Observe Electrical Power.

7. Compare with Known-Good Accessories.

8. Check Charging Protocol Requirements.

9. Consider Battery Temperature and Charge Level.

10. Perform Controlled Load Testing Where Appropriate.

11. Record Measurements and Test Conditions.

12. Use Specialised Equipment for Advanced Problems.

This approach helps technicians identify possible causes before recommending unnecessary replacement.

21. Frequently Asked Questions About FNIRSI FNAC-28

Q1. What is FNIRSI FNAC-28 used for?

The FNIRSI FNAC-28 is used for compatible USB voltage, current and power measurements, charging troubleshooting, cable comparisons and selected protocol testing.

Q2. Can FNIRSI FNAC-28 measure USB charging power?

Yes. It provides compatible USB voltage, current and power measurements.

Q3. Can FNIRSI FNAC-28 test USB cables?

It supports cable resistance testing using the manufacturer's specified procedure.

Q4. Can FNIRSI FNAC-28 test power banks?

Yes. It can assist with compatible USB power bank output measurements.

Q5. Can FNIRSI FNAC-28 measure actual battery capacity?

A complete battery capacity evaluation requires controlled discharge testing and suitable accumulated energy measurement. The FNAC-28 cannot directly measure internal battery cell capacity through the USB output.

Q6. Does FNIRSI FNAC-28 support USB PD active triggering?

No. USB PD active triggering is not supported.

Q7. Can FNIRSI FNAC-28 capture USB PD packets?

No. It does not support USB PD packet capture.

Q8. Can FNIRSI FNAC-28 test Qualcomm Quick Charge?

It provides selected Quick Charge protocol testing functions for compatible arrangements.

Q9. Can FNIRSI FNAC-28 test Samsung AFC?

It supports selected Samsung AFC protocol testing functions.

Q10. Can FNIRSI FNAC-28 test Huawei FCP and SCP?

It provides selected Huawei FCP and SCP protocol testing functions.

Q11. Why does my 65W charger only deliver 10W?

Possible causes include charging protocol incompatibility, device power demand, cable limitations or thermal charging controls.

Q12. Why is my smartphone charging slowly?

Possible causes include insufficient charging power, cable resistance, battery temperature and charging compatibility.

Q13. Can FNIRSI FNAC-28 test USB charger voltage drop?

It can assist with USB voltage measurements, but identifying the complete drop across a cable requires suitable measurement points or supported resistance testing.

Q14. Is FNIRSI FNAC-28 an electronic load?

No. A separate suitable electronic load is required for controlled load testing.

Q15. Can FNIRSI FNAC-28 test charger safety?

No. It cannot replace formal electrical safety testing or certification.

Q16. Can FNIRSI FNAC-28 test USB-C chargers?

It supports compatible USB-C electrical measurements, subject to its operating limits and protocol capabilities.

Q17. Can FNIRSI FNAC-28 verify every 100W USB-C charger mode?

No. Complete verification of USB PD high-power modes requires suitable negotiation and load testing equipment.

Q18. Is FNIRSI FNAC-28 suitable for electronics students?

Yes. It can support suitable introductory experiments involving voltage, current and electrical power.

Q19. Is FNIRSI FNAC-28 suitable for mobile phone repair shops?

Yes. It can assist with preliminary USB charging troubleshooting and accessory comparisons.

Q20. Where can I buy FNIRSI FNAC-28 in Malaysia?

Contact MTM Precision Sdn Bhd in Puchong, Selangor, for product pricing, stock availability and suitable instrument recommendations.

22. FNIRSI FNAC-28 Complete Learning Guide

For readers who want more detailed information, the FNIRSI FNAC-28 learning series covers the following topics.

USB Testing Fundamentals

Guide 1 - USB Charger and Cable Testing

Introduction to USB voltage, current, power and basic measurement applications.

Guide 2 - USB Charger Voltage and Current Testing

Practical explanation of electrical measurements and charger output behaviour.

Guide 3 - USB Cable Resistance Testing

Understanding conductor resistance, voltage drop and cable comparison methods.

Guide 4 - Fast Charging Protocol Testing

Introduction to compatible QC, AFC, FCP, SCP and other selected charging technologies.

Power Bank and Charger Troubleshooting

Guide 5 - Power Bank Output Testing

Monitoring compatible power bank voltage, current and output power.

Guide 6 - USB Charger Troubleshooting

Investigating common charger problems using systematic electrical checks.

Guide 7 - USB Charging Power and Wattage Testing

Understanding how charging power is calculated and interpreted.

Guide 8 - USB-A vs USB-C Charging Testing

Comparing USB connector types and charging capabilities.

Advanced Practical Applications

Guide 9 - Slow Smartphone Charging Diagnosis

Identifying common causes of slow smartphone charging.

Guide 10 - USB Cable Quality Comparison

Comparing cable performance and electrical characteristics.

Guide 11 - USB Charger Testing for Electronics Repair Shops

Practical workshop applications and troubleshooting procedures.

Guide 12 - Power Bank Capacity vs Output Energy

Understanding mAh, Wh and power bank energy conversion.

Guide 13 - Fast Charging Compatibility Troubleshooting

Investigating fast-charging negotiation and compatibility problems.

Guide 14 - USB Power Bank and Charger Comparison

Comparing portable battery power and wall charger performance.

Guide 15 - USB Charging Voltage Drop Troubleshooting

Understanding resistive voltage losses and charger voltage regulation.

Professional and Educational Applications

Guide 16 - USB Charger Load Testing

Using a suitable electronic load to evaluate charger output performance.

Guide 17 - USB Charging Tester for Electronics Students

Practical laboratory experiments involving voltage, current and power.

Guide 18 - USB Charger Quality Testing and Buying Guide

Evaluating charger specifications, compatibility and quality considerations.

Guide 19 - USB Charging Troubleshooting FAQ

Answers to common USB charging questions and technical problems.

These supporting guides provide more detailed explanations of individual USB testing applications.

23. Where to Buy FNIRSI FNAC-28 USB Tester in Malaysia?

MTM Precision Sdn Bhd supplies electronic testing and measuring instruments for professional, educational and technical applications throughout Malaysia.

Customers looking for a FNIRSI FNAC-28 USB Tester Malaysia can contact MTM Precision for product information, pricing and availability.

The FNIRSI FNAC-28 is suitable for customers interested in:

• USB Charger Testing

• USB Power Measurement

• Power Bank Output Monitoring

• USB Cable Resistance Testing

• Selected Fast-Charging Protocol Investigation

• Electronics Repair and Training Applications

MTM Precision serves customers in Kuala Lumpur, Selangor, Johor, Penang, Melaka, Negeri Sembilan, Perak, Pahang, Kedah, Kelantan, Terengganu, Perlis, Sabah and Sarawak.

Customers can contact our team for suitable instrument recommendations and delivery enquiries.

Please confirm current stock and availability before ordering.

Contact MTM Precision Sdn Bhd

For FNIRSI FNAC-28 USB Tester Malaysia, USB charging troubleshooting equipment and electronics measurement instrument enquiries:

MTM Precision Sdn Bhd

Showroom & Service Centre

No. 29-1 & 29-2, 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

Contact MTM Precision today for FNIRSI FNAC-28 pricing, availability and suitable USB testing equipment recommendations in Malaysia.

Conclusion

The FNIRSI FNAC-28 USB Tester is a practical instrument for monitoring electrical conditions in compatible USB charging systems.

It provides useful measurements for understanding USB voltage, charging current, electrical power, cable resistance and selected fast-charging protocols.

These functions can assist electronics technicians, repair shops, retailers, students and technical users with preliminary USB charging investigations.

However, the instrument has important limitations.

It does not replace dedicated USB PD protocol analysers, programmable electronic loads, laboratory power analysers or formal electrical safety testing equipment.

By understanding its capabilities and using suitable test procedures, users can make better decisions when evaluating USB chargers, power banks and charging cables.

For customers searching for FNIRSI FNAC-28 Malaysia, USB Tester Malaysia, USB Charger Tester Malaysia or USB Power Meter Malaysia, MTM Precision Sdn Bhd can assist with product enquiries and suitable electronics measurement equipment recommendations.