FADOS MUX Multiplexer Module

The FADOS MUX is the multiplexer module of the FADOS circuit board tester family from CBT Electronic (ProT Ar-Ge). CBT Electronic describes it as an advanced version of FADOS 9F1: the same V-I fault detection, equivalent circuit diagram, component value measurement, variable DC supply and non-contact IR temperature monitoring, with manual probing replaced by a switched channel matrix that steps through the board’s test points on its own.

The FADOS MUX is supplied with 100 channels as standard and can be cascaded to expand the channel count up to 200 channels.

That number is the first thing to check against your board. A 100-channel module covers most controller, driver and I/O boards outright. Cascading to 200 channels is what brings larger backplanes, multi-connector assemblies and panelised boards into a single unattended run instead of two fixtures and two passes.

Multiplexer: Flexible PCB Connectivity

There are two ways to get a board’s test points into the multiplexer, and the choice is usually decided by how many boards of that type you expect to see.

• Direct PCB connection. Where the board already carries a test-point connector, the MUX connects straight to it. No fixture is built, so this is the practical route for repair benches, R&D and low-volume board types.
• Bed-of-nails fixture integration. The MUX interfaces with a bed-of-nails test fixture for rapid and repeatable PCB testing. The fixture costs time to build once, then every board of that type drops in and is contacted identically, which is what makes results comparable across a production lot.

Per CBT Electronic, this flexibility is what delivers faster fault localisation, reduced testing time and higher throughput across production, repair and R&D environments.

Reference and Test Workflow

The MUX workflow is a record-then-compare cycle, and it is short enough that a technician can be productive on it the same day:

1. Configure the MUX settings such as voltage, current and frequency for the board being tested.
2. Specify the number of test points to be recorded.
3. Run Reference. The software generates V-I graphs based on the designated test points, using a known-good board.
4. Store the recorded V-I data in a designated folder on the PC. This is the golden record for that board type, and it stays useful long after the reference board itself has gone back into service.
5. Run Test. Retrieve the previously saved file from the PC and activate the TEST function to compare the board in front of you against the stored reference.

The result is reported per point. A board where everything matches reports test OK with all points in tolerance; a board that does not returns the specific point numbers that fell out of tolerance, so the technician starts at a location rather than at a symptom.

GSAS Agent: Report Summary and QR Access

GSAS Agent reads the Excel report the FADOS MUX produces, gives back the summary an engineer or auditor actually needs, and attaches a QR code that puts the full document one scan away. It runs in three connection modes:

• Offline Mode, where reports are saved locally on the system.
• Google Drive Mode, where reports are saved to Google Drive with an automatically generated QR code.
• LAN Mode, where reports are saved to a local server with a QR code for convenient access.

The report itself carries the board serial number, board name and date/time, then a header count of TOTAL, OK and OUT OF TOL points, followed by the per-point results with the voltage, frequency, current and set tolerance each point was tested at.

Technical Specifications

Specification	FADOS MUX
Multiplexer channels	100 as standard, cascadable to 200
Step of voltages	±1 V, ±3 V, ±6 V, ±12 V, ±24 V
Step of resistances	Low 47 kΩ, Med1 3.5 kΩ, Med2 700 Ω, High 250 Ω
Step of frequencies for ±6 V	Very Low 2.16 Hz, Low2 6.85 Hz, Low1 20.56 Hz, Test 54.82 Hz, High at ±1 V (Low Inductor) 7.81 kHz, High at ±3 V (Low Capacitor) 2.23 kHz
V-I test channels	2 channels: Channel 1, Channel 2
Scan modes	Manual or automatic selection steps of voltage, current and frequency
Memory function	Yes, recording data with image, and fault detection by comparison with stored signatures
Equivalent circuit diagram	Yes
Resistor, capacitor, diode measurement	Yes
Graphs	3 graphs at different adjustments can be screened simultaneously
Report saving / analytics	Yes
Variable DC power supply	100 mV to 16 V at 10 mA to 1500 mA
Non-touched IR temperature	Monitoring temperature up to approximately 120 °C above ambient
Short circuit finder + frequency scanning	No (FADOS XI only)
Oscilloscope	Sampling rate 400 K/S, ADC 2 channel 12 bit, sensitivity 2.5 mV, image rate 0.02 mS/div to 100 mS/div, instant memory 64 Kbyte, input voltage probe 1X ±5 V and 10X ±50 V
Square wave generator	0.2 to 25 kHz
Analog output signal	-12 V to +12 V
Dimensions	125 mm L x 113 mm W x 78 mm H
Gross weight	1700 grams approx.

Specifications are per the CBT Electronic and GSAS FADOS booklet (PDF), August 2026, and are subject to change without prior notice.

Ideal Applications

• Incoming inspection: verify boards received from contract manufacturers before accepting shipments, catching assembly defects, wrong-value components and solder faults
• Production-line end-of-line testing: an automated board-level quality gate before final assembly or shipment
• Golden-board verification: hold a recorded reference for each board type and test every lot against it to detect process drift or a change in component supply
• Warranty return analysis: rapidly screen returned boards to separate genuine faults from no-fault-found units
• Repair verification: confirm that a repaired board passes every configured test point before it goes back into service

CBT Electronic reports FADOS in use across automotive and EV, aerospace and defence, industrial automation, medical devices, power and energy, consumer electronics, EMS and manufacturing, telecom, and academia and research.

Why Buy from GSAS

GSAS Micro Systems is an authorized CBT Electronic engineering partner for India and supplies the FADOS MUX with the application support that actually decides whether a multiplexed setup pays back: channel budgeting against your board, test-point selection, connector versus bed-of-nails fixture guidance, and tolerance configuration on the first reference recording. Our engineers work with production and repair teams to choose the set of test points that gives the most fault coverage for the fixture complexity you are willing to build and maintain.

Talk to our applications team in Bengaluru, Chennai, Hyderabad, Pune, Mumbai, Delhi NCR or Visakhapatnam for a demonstration on your own board, with INR invoicing under GST, local stock and commissioning support.