Related Manuals for Polar Instruments Toneohm 970
Summary of Contents for Polar Instruments Toneohm 970
- Page 1 Polar Instruments Ltd Operator Manual Toneohm 970 Polar Instruments Ltd. Garenne Park Rue de la Cache St. Sampson’s Guernsey Channel Islands GY2 4AF Fax: +44 (0)1481 252476 http://www.polar.co.uk e-mail: mail@polar.co.uk MAN 175-9904...
- Page 3 TONEOHM 970 OPERATOR MANUAL 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 the Warranty Period.
- Page 5 POLAR INSTRUMENTS (UK) LTD 11 College Place London Road Southampton England SO1 2FE Harmonised standards applied in order to verify compliance with these Directives: EN 50081-1:1992 EN 50082-1:1992 EN 61010-1:1993 DECLARATIONS • • • • i TONEOHM 970 OPERATOR MANUAL...
- Page 6 Power cord color codes are as follows: Europe brown live blue neutral green/yellow earth (ground) United States black live white neutral green ground ii • • • • SAFETY WARNING TONEOHM 970 OPERATOR MANUAL...
- Page 7 Use only the accessories (e.g. test probes and cables) provided by Polar Instruments. The unit must be maintained and repaired by a skilled electronics technician in accordance with the manufacturer’s instructions.
- Page 8 Always disconnect the board under test from the local mains supply (including ground) before using this instrument. The Toneohm 970 applies test voltages to the item under test. Make sure that the item under test is isolated from all other sources of electrical power.
- Page 9 RH 80% maximum at 31°C — derate linearly to 50% at 40°C Mains borne transients As defined by Installation Category II (Overvoltage Category II) in IEC664 Pollution Degree 2 (IEC664) SPECIFICATIONS • • • • v TONEOHM 970 OPERATOR MANUAL...
- Page 10 Enclosure to UL94 V-0. SYMBOLS CAUTION To prevent damage to this product and to ensure its safe use observe the specifications given in this manual when connecting to terminals marked with this symbol. vi • • • • SYMBOLS TONEOHM 970 OPERATOR MANUAL...
- Page 11 Lightweight Headphones EPM115 Optional Accessories Bare-board Stimulus Lead set (0.025") ACC121/XG25 Bare-board Stimulus Lead set (0.031") ACC121/XG31 Bare-board Stimulus Lead set (0.040") ACC121/XG40 Bare-board Lead set (universal) ACC154 Service Manual MAN177 ACCESSORIES • • • • vii TONEOHM 970 OPERATOR MANUAL...
- Page 12 GUIDE TO THE MANUAL Introduction Overview of the Polar Instruments Toneohm 970. Installation/set up Instructions for installing and setting up the Toneohm 970. Toneohm 970 description Description of the Toneohm 970 controls and probes. Toneohm 970 operation Detailed operation of the Toneohm 970.
- Page 13 GUIDE TO THE MANUAL viii CONTENTS INTRODUCTION TO THE TONEOHM 970 INSTALLING THE TONEOHM 970 2.1 Unpacking ....................2 2.2 Connecting the Toneohm 970 to a power supply........2 2.3 Self test ....................3 CONTENTS • • • • ix TONEOHM 970 OPERATOR MANUAL...
- Page 14 Drive Level ..................... 5 3.4 Sensitivity Ranges................... 5 Track Shorts ..................5 3.5 Current Trace..................6 LOCATING FAULTS WITH THE TONEOHM 970 4.1 Range selection ..................7 4.2 (Low resistance) shorts ................7 4.3 Plane Shorts ..................10 Causes of shorts on multi-layer boards ..........10 Connecting the Plane Stimulus leads...........
- Page 15 SECTION 1 — INTRODUCTION INTRODUCTION TO THE TONEOHM 970 The Toneohm 970 has three operating modes to enable the user to physically locate any type of short circuit without cutting traces or otherwise damaging the board under test: Track Shorts Milliohmmeter with five sensitivity ranges for locating low resistance shorts.
- Page 16 2.2 Connecting the Toneohm 970 to a power supply Refer to the voltage label on the rear panel of the instrument and make sure that the marked rating is suitable for the local mains power supply.
- Page 17 WHITE NEUTRAL GREEN GROUND Check that the Toneohm 970 mains switch (on the rear panel) is OFF. Plug the power cable into the receptacle on the rear panel of the Toneohm 970. Plug the other end into a wall outlet.
- Page 18 When the headphones are connected to this socket the internal speaker is switched off. Use only 3.5mm stereo jack plugs in this socket. A stereo to mono adapter is required for use with an earpiece. 4 • • • • TONEOHM 970 DESCRIPTION TONEOHM 970 OPERATOR MANUAL...
- Page 19 Use the LOW through HIGH ranges for locating low resistance shorts. These ranges are sensitive enough for measuring trace resistance. HIGH is approximately five times more sensitive than LOW. TONEOHM 970 DESCRIPTION • • • • 5 TONEOHM 970 OPERATOR MANUAL...
- Page 20 A tone is produced whose frequency is proportional to the displayed amplitude (low magnetic field intensity causes low frequency tone). 6 • • • • TONEOHM 970 DESCRIPTION TONEOHM 970 OPERATOR MANUAL...
- Page 21 LOW range, should isolate the fault to within a few millimetres. In situations where traces are thick, more sensitivity and resolution can be gained using the HIGH range. LOCATING FAULTS WITH THE TONEOHM 970 • • • • 7 TONEOHM 970 OPERATOR MANUAL...
- Page 22 On some multi-layer boards, where very little trace is exposed, the milliohm technique may be difficult to use. In this case see Section 4.4 — CURRENT TRACING (NON-CONTACT). 8 • • • • LOCATING FAULTS WITH THE TONEOHM 970 TONEOHM 970 OPERATOR MANUAL...
- Page 23 Use different sensitivity ranges as necessary. SHORT Figure 4-1 Low Resistance Short LOCATING FAULTS WITH THE TONEOHM 970 • • • • 9 TONEOHM 970 OPERATOR MANUAL...
- Page 24 Connect the four Plane Stimulus leads to the corners of the shorted plane as shown in Figure 4-2. RED LEAD BLUE LEAD YELLOW LEAD GREEN LEAD Figure 4-2 Plane Stimulus Connection 10 • • • • LOCATING FAULTS WITH THE TONEOHM 970 TONEOHM 970 OPERATOR MANUAL...
- Page 25 • If no tone is produced, turn the Drive Level control anti-clockwise (to reduce the sensitivity) until a tone is heard. LOCATING FAULTS WITH THE TONEOHM 970 • • • • 11 TONEOHM 970 OPERATOR MANUAL...
- Page 26 If a reading greater than 3.0 is displayed this indicates there may be multiple shorts. (Refer to MULTIPLE SHORTS later in this section.) 12 • • • • LOCATING FAULTS WITH THE TONEOHM 970 TONEOHM 970 OPERATOR MANUAL...
- Page 27 High Resistance Shorts When the resistance of the short is greater than 20–30 Ω then the Toneohm 970 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 28 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 • • • • LOCATING FAULTS WITH THE TONEOHM 970 TONEOHM 970 OPERATOR MANUAL...
- Page 29 (this occurs with high resistance shorts, i.e. above 150 Ω). • To alter the distance over which the probe detects current, adjust the Drive Level control. LOCATING FAULTS WITH THE TONEOHM 970 • • • • 15 TONEOHM 970 OPERATOR MANUAL...
- Page 30 The board is first divided into four sectors (see Figure 4-3). DRIVE SOURCE Figure 4-3 Board Sectoring 16 • • • • LOCATING FAULTS WITH THE TONEOHM 970 TONEOHM 970 OPERATOR MANUAL...
- Page 31 20mm square. Use of the circuit diagram, combined with knowledge of the current path can often identify a likely place for a short (e.g. two adjacent IC pins). LOCATING FAULTS WITH THE TONEOHM 970 • • • • 17 TONEOHM 970 OPERATOR MANUAL...
- Page 32 (IPA) may be used. Do not spray cleaners directly onto the instrument. 5.4 Technical Support For technical support contact your local Polar Instruments distributor or Polar Instruments. 18 • • • • LOCATING FAULTS WITH THE TONEOHM 970 TONEOHM 970 OPERATOR MANUAL...
- Page 33 If the short resistance exceeds 1Ω, it is probable that a defective component is the cause of the fault. QUESTIONS ON PLANE SHORTS • • • • 19 TONEOHM 970 OPERATOR MANUAL...
- Page 34 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. 20 • • • • QUESTIONS ON PLANE SHORTS TONEOHM 970 OPERATOR MANUAL...
Need help?
Do you have a question about the Toneohm 970 and is the answer not in the manual?
Questions and answers