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Customer story
Established in the late 1800s, Megger
designs and manufactures test and measurement instruments that perform electrical
measurements for preventative maintenance, trouble-shooting and commissioning
purposes.
A first-time user of boundary-scan technology, Megger turned to JTAG Technologies to
help test a new range of Portable Appliance
Test (PAT) units. Freddie Chin, Project Manager of Megger in Dover, England, recounts
the story.
“JTAG Technologies helped develop the optimum test solution.”
The name Megger is synonymous with portable
electrical test equipment and the company is always
striving to bring high-performance products to market. Recently, the company designed a new family of
Portable Appliance Test (PAT) testers with an impressive range of features including: an internal database
for results storage, rapid start-up and instant re-start
after temporary disconnection when moving between
test locations.
“Each member of the family contains four analogue /
mixed-signal cards and a processor card - which we
wanted to be common to all family members,” comments Chin.
Megger selected the credit-card-sized SODIMM
form-factor for the processor card; which contains an
Atmel processor, NOR and NAND Flash, SDRAM and
an Ethernet IC. The card’s 200-pin edge connector
interfaces with the analogue / mixed-signal cards plus
a TFT display.
Chin: “As part of our manufacturing processes we
would normally test the card using ATE bed-of-nails,
but with components – including three BGAs - moun-
ted on both side of the board that was not an option.
We simply had no room for test points.”
However, one device – the Atmel processor – is
boundary-scan capable. Could that be utilised? Megger consulted JTAG Technologies, who established that
even with just one boundary-scan device available
test coverage of circa 75% would still be possible.
The solution devised was a dedicated test card that
mates with the 200-pin edge connector of the processor card. The test card has two JTAG headers – one to
access the Atmel device, the other to control boundary-scan devices that connect to the edge connector;
and thus access many nets on the processor card.
“By connecting the processor card to the test board,
and controlling it via boundary-scan, we can exercise
all of the signal lines on the 200-pin connector,” says
Chin. “If there’s a track or connector pin damaged, or
shorts between SMD pins/pads, the interconnect test
would find it. Then, having confirmed the interconnects, we’re able to check the correct fit and read the
IDs of the memory devices.”
...We are boundary-scan.®
Customer story
Megger
Megger uses JTAG Technologies’ Runtime and Visualizer tools to pin-point any manufacturing problems,
where the latter works by superimposing the boundary-scan application on to the PCB layout / schematic.
“These tools enabled us to refine our manufacturing
processes when we entered production,” recalls Chin,
“and helped us make judgement calls on rework - if
the fault was with the seating of an SMD resistor pack,
for example, or say if a BGA hadn’t seated properly,
we could adjust stencils and tune the reflow oven.
We’re now very close to 100% yield, and JTAG Technologies’ tools and advice got us there. JTAG Technologies was also extremely accommodating in terms
of licensing - giving us time to evaluate the tools and
providing training.”
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United Kingdom & Ireland
Germany
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Taiwan, Thailand & South Korea)
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