The following companies are a few of those that have joined the growing ranks of ECT test customers during the past few months.

Triangle Circuits, of Oakmont, PA, purchased their first Series 9090 grid test system to provide inexpensive topside access and increase throughput. Triangle manufactures multilayer SMT boards in prototype and medium volume production.

Viktron purchased two 9090 grid test systems. One will be used in the ESS Division, in West Chicago, Il. The second system was installed at the PEC Division, in Orlando, FL. The PEC and ESS divisions produce high-volume printed circuits. Both systems were purchased to enhance throughput and reduce fixture costs.

Toppan West installed their first Series 9090 grid test system with the HyperSort" Auto Unloader/Sorter. Toppan produces high-volume and quick-turn printed circuits in Visalia and San Diego, CA. The tester will be used to increase throughput and eliminate test escapes in the San Diego facility.

Circuitest Services purchased their first Series 9090 grid test system. Circuitest is a multi-site testing service with facilities in Nashua, NH; San Jose, CA; Huntington Beach, CA and the United Kingdom. Circuitest specializes in testing close-center product through finished backplanes.

SAT, France. SAT has purchased their first Series 9090 tester with a Double DenseGrid Adapter and MAS Alignment system. It will be installed in their new facility in Lannion, France. SAT manufactures military and telecommunications PCBs for use in other SAT divisions.

ElectroTek, Oak Creek, WI, purchased the latest series 9090 tester to increase throughput in high-volume PCMCIA test applications. Using fast-loading, dense-spacing ValuGrid test fixtures has enabled ElectroTek to dramatically reduce fixture costs. ElectroTek is a leading manufacturer of PCMCIA boards.

Herco Technology, San Diego, CA, has installed a third Scorpion dedicated bare board testing system. The system is configured with 10,000 test points to test printed circuit boards in a very high volume production manufacturing operation.

Attendees at the recent IPC Printed Circuit Expo, in San Diego, CA, had an opportunity to see how the new HyperSort Auto-unloader, docked to a 9090 Series test system, can virtually double throughput in the bareboard test arena. Cycle times to load, test, pass/fail mark, unload and sort a board averaged 10 seconds.

Visitors were especially interested in the ease with which the HyperSort module is docked to the 9090 tester. Single-point docking - plus the module's large casters - make it easy to move the HyperSort module between multiple 9090 testers depending on board volume and test requirements.

Demonstrations of several solutions for multiple density grid applications were also demonstrated at the IPC Expo. Users of ECT ValuGrid" fixturing technology are well aware of the tremendous density advantages offered by this fixturing. ValuGrid can displace test pins by as much as .700", providing relief from multiple density grid requirements.

Double and Quad DenseGrid adapters were demonstrated on a 9090 test system. DenseGrid adapters, used in conjunction with ValueGrid fixtures, provide the maximum density, cost-effective bare board testing available today.

IPC was very well attended and, for the first time in many years, the PCB fabrication industry has its own dedicated trade exhibition as an important component of the ongoing IPC education program.

A simple pin sorter will expedite the sorting of mixed ValuGrid pins, featureless pins, or feature included pins, such as those used in InterTrace's Fixture 2000. A feature-included pin is distinguished by a feature that is smaller than the diameter of the pin. A pin sorter would not work for crimp or pinch pins with a pin feature that exceeds the pin diameter.

The pin sorter we've illustrated uses interchangeable sorting plates drilled on a universal pattern. The sorting plate drilled for the smallest diameter pins is mounted first, and handfuls of mixed-diameter pins are shuffled over the plate in the same way that pins are loaded into a ValuGrid fixture. The smallest diameter pins will fall into the catch box. This procedure should be repeated several times until you think that all pins of the appropriate diameter have fallen into the catch box. Remove the plate, empty the catch box, install the sorting plate for the next largest pin diameter, and repeat the process.

Pin Sorter

Please note that different vendors use pin diameter values that may vary by ± .001" from those referenced here.

It is recommended that only two or three pin diameters should be selected. For example, choose .051" diameter pins for through holes and .019" diameter pins for surface mount pads.

Some .031" diameter pins may be necessary for smaller diameter holes. Smaller diameter holes may have an annular ring and/or solder mask in close proximity that may prevent the .051" pin from making repeatable contact. Using a .031" pin may produce better results.

By limiting standard pin diameters to two or three styles, identification is easier and loading and sorting procedures become much more productive. The disparity in pin diameters will also allow you to use a larger hole diameter for the .019" sorting plate .035" to .040" for example - instead of the fairly tight plate required to distinguish .019" pins from .031 "pins, and the extreme difficulty of distinguishing or sorting .019" pins from .023" pins.

We recommend that either .019"or .023" pins be selected as the standard for testing pads. Since it is extremely difficult to separate .016" from .019" pins, we also recommend that .016" pins be used only for extremely tight spacing requirements, and only used in that fixture. Unload .016" pins carefully to keep them separate from .019" or.023" pins.

Headed pins cannot be sorted using this method. You may still use some headed pins, but they are easily hand sorted on removal from the fixture.

The sorting plate is a .062" or .093" plate of the same dimensions as the smallest ValuGrid kit (12"xl0"). It should be drilled on .100" or .075" centers to a grid of approximately 8" x 6". The catch box and bin can be made of a variety of materials (cardboard, plastic, sheet metal). It is probably best to find containers or bins already in use within your facility to save time and expense.

In the February issue, we discussed the importance of cleaning the test probe field. We continue our field service feature with a review of probe field maintenance.

By verifying the performance of each test probe, you ensure the long-term performance of your tester. Checking the pin field to a resistance level that is within your test parameters will result in better performance and lower costs. The only real consumable for the 9090 test system is the eventual fatigue and possible failure of the probes located in the probe field.

Probe resistance testing is the only true solution for prevention of wholesale probe field replacement. An important time and money saving feature of the 9090 is the ability to test the integrity of the pin field. Most of you who have owned a universal grid tester have faced the agony and expense of replacing the entire probe field. Replacement of the entire probe field is usually the result of pin fatigue, plating erosion or contamination.

Grid replacement is very costly. 40,000 test points can cost as much as $14,000, plus several days of downtime while probes are replaced.

The 9090 is designed with a number of standard features which eliminate these expenditures. One to two minutes per week is all it takes to replace individual probes as they fail or become weak -- a far better choice than waiting until the test grid fails to function properly. And each week of testing may result in the replacement of perhaps two to five probes at a cost of only $1.00 to $2.00.

This level of weekly probe field maintenance will ensure that test results are accurate and that the tester is operating to the lower resistance parameters required by your customer or QA department. The grid can be 100% verified to less than 1 ohm, although the usual continuity test parameters are 10-50 ohms. Simply perform the probe field test at a value less than your normal continuity test to ensure that the tester is not indicating opens caused by the probe field.

Combined with a thorough weekly grid cleaning, the Probe resistance test (which is standard in the 9090 tester maintenance diagnostics) will provide years of service without the need for dramatic probe field replacement. Contact your local ECT Field Service Representative for proper cleaning method.

The procedure for conducting a grid Performance and resistance test requires only one to two minutes, plus another minute or two to replace probes.

In less than 90 days following the introduction of the HyperSort system at NEPCON West 95, the auto unloader/sorter has received excellent reviews and produced a number of orders. Response at the IPC Expo was also enthusiastic, and our Sales Engineers will be busy working with 9090-Series customers to retrofit HyperSort to existing 9090 testers, or as a module to new 9090 system orders.

The dramatic doubling of test throughput is obviously the primary appeal of the HyperSort module, but customers have been quick to tell us what a great job our engineers have done to make the module truly user-friendly. The simplicity of the single-point, pneumatic latch docking mechanism is particularly appealing. Docking can be accomplished in only two minutes.

Customers with multiple 9090 testers recognize how easily they can dock and undock the HyperSort module for shared duty as dictated by changing board types and test volume. Large diameter casters facilitate movement of the module.

HyperSort convenience and safety features also received high marks from our customers and show attendees. They noted the wide, pneumatically operated sliding door that provides access to the elevator stacks, and the eye-level LCD screen that displays board-count data. Safety features include positive interlocked access covers and bump sensors at the unloader rail ends.