FADOS 9F1 Advanced Features: Powered Board Testing and IR Thermal Scanning

Beyond Power-Off Testing

VI curve tracing in its standard form is a power-off technique. You apply a controlled AC stimulus to an unpowered component, measure the resulting voltage-current relationship, and compare it against a known-good reference. This works exceptionally well for identifying shorts, opens, and degraded passive components. But certain fault classes, intermittent failures, thermal drift, and voltage-dependent semiconductor breakdowns, only manifest when the board is powered and operating under load.

The FADOS 9F1 addresses this gap with two capabilities beyond power-off signature analysis: a built-in programmable DC power supply and a non-contact infrared temperature sensor.

The Built-In Programmable Power Supply

The 9F1 integrates a programmable DC power supply with the following specifications:

• Output range: 100 mV to 16 V DC
• Current limit: 10 mA to 1500 mA
• Voltage/current monitoring: Real-time readout within the FADOS software

How Powered Testing Works

The diagnostic workflow begins with conventional power-off VI curve scanning. Once the technician has identified suspicious areas, or confirmed that power-off testing alone cannot isolate the fault, they switch to powered mode.

Step 1: Set a current limit. Before applying voltage, the technician sets a conservative current limit (typically 100–200 mA for initial investigation). This protects both the board under test and the FADOS unit.

Step 2: Ramp voltage slowly. Starting from 0 V, the technician increases voltage in incremental steps while monitoring current draw. A healthy board follows a predictable current profile as each voltage rail activates its associated circuitry.

Step 3: Watch for current anomalies. A sudden current spike at a specific voltage indicates a fault on the power rail that activates at that voltage. The FADOS software logs the exact voltage and current at which the anomaly occurs, giving the technician a precise starting point for localized probing.

Step 4: Isolate the fault. With the board still powered at just below the fault threshold, the technician uses the VI probe to test individual components in the suspect area, comparing powered signatures against the reference database.

Practical Applications

This technique is particularly effective for:

• Shorted decoupling capacitors that only draw excessive current when their associated rail is active
• Partially failed voltage regulators that pass power-off testing but cannot maintain regulation under load
• Semiconductor junction degradation where the device conducts normally at low voltage but breaks down at operating voltage
• Solder joint failures that only manifest under thermal expansion from powered operation

Non-Contact IR Thermal Scanning

The 9F1’s second advanced feature is a non-contact infrared temperature sensor integrated into the diagnostic workflow.

The Thermal Fault Localization Method

When a board has a short circuit or excessive current draw, the faulty component dissipates more power than its neighbours. Even a brief powered period, 5 to 15 seconds, is enough for a shorted component to heat measurably above ambient temperature.

The workflow is straightforward:

1. Power the board briefly using the built-in supply (with current limiting)
2. Remove power
3. Immediately scan the board with the IR sensor
4. The FADOS software highlights temperature differentials, flagging components that are anomalously warm

This technique is non-destructive. The brief powered period with current limiting prevents catastrophic failure, and the IR sensor never contacts the board surface.

Where Thermal Scanning Excels

• BGA and QFN packages where solder joints are hidden beneath the component, you cannot visually inspect them, but a thermally stressed joint creates a detectable hot spot
• Multi-layer boards where inner-layer shorts are invisible from the surface but generate localized heating
• Dense SMT assemblies where hundreds of 0201 or 0402 passives make visual inspection impractical

Combined Workflow: Power-Off, Power-On, Thermal

The most effective 9F1 diagnostic sequence combines all three approaches:

1. Power-off VI scan: Catch the obvious faults, shorts, opens, missing components
2. Powered ramp test: Identify voltage-dependent faults and current anomalies
3. Thermal scan: Localize the exact component responsible for any excess current draw

For workshops in Bengaluru, Hyderabad, Chennai, and Pune that handle complex multi-layer boards, automotive ECUs, industrial controllers, medical devices, this three-phase workflow converts what might be hours of oscilloscope probing into a structured 15–30 minute diagnostic sequence.

Why Buy FADOS 9F1 from GSAS

GSAS Micro Systems is an authorized ProT Ar-Ge partner and ODM assembler for the FADOS product line. Every FADOS 9F1 shipped in India is assembled and tested at our Bengaluru facility. We provide:

• On-site demonstrations at our offices in Bengaluru, Hyderabad, Chennai, Pune, Mumbai, and Delhi NCR
• Operator training covering power-off VI testing, powered diagnostics, and IR thermal scanning
• INR invoicing with GST-compliant documentation
• Local calibration and service: no international shipping for repairs

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