Toneohm 850a 
(Information only)

A significant percentage of PCB failures are caused by short circuits and bus faults. Independent analysts place the figure as high as 40% for assembly faults, and 30% for in-service faults.

While shorts can be detected by ATE or conventional fault detection techniques, their physical location is not accurately diagnosed. The problem is being compounded by the use of densely-packed surface-mount components and bus-structured circuits, which make test access difficult.

To quickly and accurately locate shorts with the minimum of rework, you need a dedicated PCB test tool. Scrapping today's high technology boards is simply not a viable option.

Pinpoints PCB short circuits & bus faults
Reduces scrap and minimizes rework
Suitable for bare and loaded PCBs
Ideal for MDA/ATE rework & field service

Polar's Toneohm 850A is an ideal tool for electronics production and field service. Able to quickly and accurately locate shorts on both bare and loaded PCBs, it offers a very cost-effective means of minimizing repair and rework of faulty PCBs that have been identified by pass/fail testing on an MDA or ATE system. By combining milliohm and microvolt measurement capabilities with sensitive, non-contact, current-tracing facilities, the 850A is also able to locate most types of PCB shorts that occur during in-service use. These include the type of low resistance faults - soft shorts - that are caused by failing decoupling capacitors and 'stuck-at' logic devices, which often pose considerable problems for field service. If your problem is mainly plane-to-plane shorts on multilayer PCBs, please ask for details of Polar's Toneohm 950.

Simplicity of operation

Designed for use by non-technical operators, the Toneohm 850A provides a non-destructive means of tracing short-circuits to their point of origin. The instrument offers three operating modes, which cover virtually all categories of hard and soft PCB shorts, including etch problems, solder bridges, stuck bus lines and faulty decoupling capacitors.

In addition to high-sensitivity Resistance and Voltage modes, the Toneohm 850A provides a completely non-invasive means of monitoring PCB track current - without requiring you to break or cut the circuit. Employing a non-contact current-sensing probe, the Current Trace mode facilitates easy location of Vcc-to-ground shorts, and of faults in bus-structured boards such as backplanes and memory banks. A liquid crystal display provides clear indication of relative signal strength, and an audio tone enables you to walk the probes along the shorted tracks without even looking at the instrument - the highest tone will indicate the short.