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Summary of Contents for Polar Instruments Toneohm 950A
- Page 1 Multi-Layer Shorts Locator User Guide Toneohm 950A MULTI-LAYER SHORTS LOCATOR Polar Instruments Ltd Polar Instruments Ltd. Garenne Park St. Sampson Guernsey Channel Islands GY2 4AF ENGLAND email: polarcare@polarinstruments.com https://www.polarinstruments.com MAN 209–2411...
- Page 3 Toneohm 950A User Guide Polar Instruments Ltd. Hardware warranty Product Warranty. Product hardware is warranted to be free from defects in material and workmanship during the Warranty Period (as defined below). Product hardware is warranted to conform substantially to Polar’s then current (as of the date of Polar’s product shipment) published user documentation during...
- Page 4 COPYRIGHT Copyright 2024 © by Polar Instruments Ltd. All rights reserved. Due care was exercised in the preparation of this document. Polar Instruments Ltd. shall not be liable for errors contained herein or for incidental or consequential damages in connection with furnishing, performance, or use of this material.
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Page 5: Declarations
Toneohm 950A User Guide DECLARATIONS EUROPEAN COMMUNITY DIRECTIVE CONFORMANCE STATEMENT Product: Toneohm 950A This product conforms to all applicable EC Council Directives, including: EC Council Directive 2014/30/EU (commonly referred to as “the EMC Directive”) on the approximation of the laws of the Member States relating to electromagnetic compatibility. -
Page 6: Safety
United States black live white neutral green ground POWER SUPPLY The Toneohm 950A is fitted with a universal power supply – the power source input range is within AC 90 – 250 volt, 50 / 60 Hz iv • SAFETY... -
Page 7: Toneohm 950A Operation
Operating environment The Toneohm 950A is designed for use indoors in an electrical workshop environment at a stable work station comprising a bench or similar work surface. Use only the accessories (e.g. test probes and clips) provided by Polar Instruments. -
Page 8: Specifications
Toneohm 950A User Guide Specifications Track Resistance Ranges 40mΩ, 200mΩ, 2Ω, 200Ω, 2KΩ, 20KΩ. Accuracy ± 20% of FSD in 40mΩ, ±6%, ±5% of FSD in 200mΩ, ±5%, ± 1% of FSD in 2Ω το 20ΚΩ Probe voltage 260mV maximum. -
Page 9: Environmental Operating Conditions
Toneohm 950A User Guide Environmental Operating Conditions The instrument is designed for indoor use only under the following environmental conditions: Altitude Up to 2000m Temperature +5°C to +40°C ambient Relative humidity RH 80% maximum at 31°C — derate linearly to 50% at 40°C... -
Page 10: Guide To The Manual
Introducing Polar Instruments Toneohm 950A Getting started with the Toneohm 950A operating modes Toneohm 950A Using Toneohm 950A Using the Toneohm 950A’s operating functions: Ohms – Track Using the Toneohm’s milli-ohmmeter for Resistance locating low resistance shorts. Plane – Plane Use the Toneohm’s Vector Plane... -
Page 11: Table Of Contents
Introduction to the Toneohm 950A Multi-Layer Shorts Locator Toneohm 950A operating modes Installing Toneohm 950A Unpacking Connecting the Toneohm 950A to a power supply Connectors and probes Toneohm 950A probes Probe color coding Plane probe Current Trace probe and Drive Source leads... - Page 12 Ranges Track Resistance Track Voltage Trace Toneohm 950A display Plane Shorts Active / direction arrows Getting started with the Toneohm 950A Online tutorial guides Self-test Using the Toneohm 950A Shorts Locator The Toneohm 950A Front Panel Mode/function control The Toneohm 950A screen...
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Page 13: Introduction To The Toneohm 950A
Used when tracing loading faults on very low resistance tracks. Plane – Plane Shorts Used on multilayer boards to locate shorts between a track and plane or between two planes. Introduction to the Toneohm 950A • 1... -
Page 14: Installing Toneohm 950A
Power cord to suit location Retain the packaging for possible future use. NOTE: If the Toneohm 950A has been shipped or stored in a cold environment, allow the instrument to reach the temperature of its new location before applying power. -
Page 15: Connectors And Probes
Toneohm 950A User Guide Connectors and probes Toneohm 950A probes The instrument is supplied with sets of probes to support the operating functions. Each probe fits into a unique socket on the front panel. Probe color coding Probes are color coded to match the probe connection color as shown in the connectors below. -
Page 16: Plane Stimulus Leads
• Sensitivity – (if available in the selected mode) then rotate to change sensitivity/drive source voltage Volume/Mute The Volume/Mute control • Adjusts the volume of the speaker or headphone output. Press to mute/unmute. 4 • Toneohm 950A Multi-Layer Shorts Locator... -
Page 17: Ranges
Toneohm 950A User Guide Ranges Track Resistance Resistance ranges: ~40 mΩ, 200 mΩ, 2 Ω, 20 Ω, 200 Ω, 2 KΩ and 20 KΩ A low resistance generates a high tone, and a high resistance generates a low tone. On the 200 mΩ range resistances below 15 mΩ... -
Page 18: Toneohm 950A Display
Toneohm 950A User Guide Toneohm 950A display The Toneohm 950A display is a touch display module. The touch display module – shown above in Plane mode – allows for touch control of modes, Volts/mVolts and resistance ranges and drive source and also gives an indication of the parameter being measured in the units appropriate to the selected range. -
Page 19: Getting Started With The Toneohm 950A
During the self-test, the front panel screen is exercised in sequence. Do not operate front panel controls during the self-test. If the test passes, the instrument is left in the last operating mode used Getting started with the Toneohm 950A • 1... -
Page 20: Using The Toneohm 950A Shorts Locator
Volume(Rotate)/mute control (Press) VPS drive connectors Current Trace probe connector Ohms/Volts needle probes connector Plane probe connector 3.5mm headphone/speaker socket – when the headphones are connected to this socket the internal speaker is switched off. 2 • Toneohm 950A Multi-Layer Shorts Locator... -
Page 21: Mode/Function Control
• In Trace mode – adjust Drive Source • In Plane mode – adjust Sensitivity • In Volts mode – adjust Drive Source below Sensitivity Adjustment Press to mute/unmute or Rotate to: • Adjust Speaker / Headphone volume Using the Toneohm 950A Shorts Locator • 3... -
Page 22: The Toneohm 950A Screen
Toneohm 950A User Guide The Toneohm 950A screen The Toneohm 950A screen (shown in Plane mode above) reflects: • The mode selected: Ohms, Volts, Trace or Plane • The numerical reading associated with the mode (Volts, Ohms in their respective... -
Page 23: Locating Faults With The Toneohm 950A
The table below indicates the suggested range for locating different types of short circuit. Type of fault Mode/Range Shorts below 200 mΩ Ohms – 2Ω, 200 mΩ Multi-layer shorts (static) Plane (plane shorts) Locating faults with the Toneohm 950A • 5... -
Page 24: Ohms - Low Resistance Shorts
PCB and apply sufficient pressure to pierce flux and solder resist. Probe the track at different points rather than scraping the probe along its length. 6 • Toneohm 950A Multi-Layer Shorts Locator... - Page 25 When the reading is below about 15 mΩ, the probes should be within a few millimetres of the short and the tone changes to a warble. Locating faults with the Toneohm 950A • 7...
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Page 26: Plane - Locating Plane Shorts
PCB plane – do not connect to PCB tracks The Plane range is effective in physically locating shorts between a track and a plane, or between two planes. The Plane screen comprises: 8 • Toneohm 950A Multi-Layer Shorts Locator... -
Page 27: Causes Of Shorts On Multi-Layer Boards
Thus, it is usually possible to locate the short to a point that is accessible from the surface of the board. Connection Connect the four Plane Stimulus leads to the corners of the shorted plane as shown below – Plane Stimulus Connection. Locating faults with the Toneohm 950A • 9... - Page 28 • Enter Plane mode • Check the Plane Stimulus leads are connected correctly, • If the warning beep sounds and the 950A returns to Missing Plane Drive, check that all the Plane Stimulus leads are 10 • Toneohm 950A Multi-Layer Shorts Locator...
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Page 29: Sensitivity Adjustment
Note that increasing the resolution is usually only required when locating a high resistance short. Locating faults with the Toneohm 950A • 11... -
Page 30: Operation (Single Short)
+5V and ground may not be consistently connected to the same side of these components. 12 • Toneohm 950A Multi-Layer Shorts Locator... -
Page 31: Example #2
High Resistance Shorts When the resistance of the short is greater than 20–30 Ω then the Toneohm 950A will not be able to resolve its position as precisely as for a "hard short". Resolution can be improved by moving the positions of the Drive Stimulus leads to reduce the area of the plane being stimulated. -
Page 32: Multiple Shorts
Alternatively, divide the board into rectangular sections and treat each section separately. If the arrows direct the user to the edge of a rectangle and the fault is not evident at this location, stimulate the area adjacent to that edge. 14 • Toneohm 950A Multi-Layer Shorts Locator... -
Page 33: Trace - Current Tracing (Non-Contact)
Its amplitude can be adjusted using the Sensitivity control. The peak current supplied is approximately 100mA Current Trace Probe Trace uses the non-contact Current Trace Probe to detect the magnetic field intensity of current flowing from the Trace Locating faults with the Toneohm 950A • 15... -
Page 34: Connection And Sensitivity Adjustment
PCB layout. A recommended approach is to move the injection points of the Drive Source around the board to determine in which regions there is current flowing. The board is first divided into four sectors (see Board Sectoring graphic below.) 16 • Toneohm 950A Multi-Layer Shorts Locator... -
Page 35: Bus Faults (Stuck Nodes)
(for example, two adjacent IC pins). Bus Faults (Stuck Nodes) Where a static fault exists between two points that have no parallel capacitors, Trace can be used to locate the fault. Locating faults with the Toneohm 950A • 17... - Page 36 Drive Source leads. Pass the Probe over each suspect IC, probing each IC pin in turn. The defective IC will be conducting Drive Source current through its substrate, which will be detected by the probe. 18 • Toneohm 950A Multi-Layer Shorts Locator...
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Page 37: Edge Connectors
4. Note that if the short was on the edge connector nearest to the Drive Source leads, no tone would be generated when the Probe moved between connectors 1 and 2. Locating faults with the Toneohm 950A • 19... -
Page 38: Faulty Decoupling Capacitors
The reading at D would be the lowest (only C5's current.) If C3 were open circuit, the readings at B and C would be equal. This method is most suitable for capacitors in the range 0.1uF to 1.0uF. 20 • Toneohm 950A Multi-Layer Shorts Locator... -
Page 39: Volts/Mvolts - Track Voltage Measurement
As the tone is proportional to the voltage measured, it is usually sufficient to follow the tone change rather than check readings. Locating faults with the Toneohm 950A • 21... - Page 40 Note that if the Drive Source leads had been connected across C3, all voltage measurements would be zero. If this happens, the solution would be to move one of the leads, e.g. to C2 22 • Toneohm 950A Multi-Layer Shorts Locator...
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Page 41: Application Note: Questions About Plane - Plane Shorts
What if the short resistance is greater than 30 If the resistance of the short is high, the resolution of the Toneohm 950A is reduced. Moving the Plane Stimulus leads to stimulate a smaller area of the board will help compensate for this. - Page 42 Two of the Direction Arrows are lit at the same time. This also indicates that the probe is close to the short. Ignore the Arrows and use the probe to find the lowest displayed reading. 24 • Toneohm 950A Multi-Layer Shorts Locator...
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