russ lavergne
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 Posted:
Sun Dec 11, 2005 9:35 am Post subject:
High end pcb repair equipment question... |
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I was looking at some of the very expensive test equipment used to
troubleshoot circuit boards and it seems that they all use the Huntron type
of testing. Injecting an AC signal and then viewing the results on a screen
and then comparing that to a working board. Equipment made by Polar, ABI,
QMAX, and it seems most of the people who make industrial test stuff where
you place the board under a bed of nails type test fixture. My questions
is, is this the only method that us used to troubleshoot complex pcbs? If
so is there a good web site that covers the details of how this is done? I
guess there are many variations on this method but none of them are perfect?
are they? Even with one of these systems and a known working board can you
still be unsure of what is exactly wrong with the board? And... Are there
any other radically different types of systems used to troubleshoot complex
circuit boards and how might they work?
Thanks for the info
Russ
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DaveM
Guest
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Mon Dec 12, 2005 1:35 am Post subject:
Re: High end pcb repair equipment question... |
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Hi Russ,
The Huntron testers are used to manually troubleshoot a circuit. They can
be used on very simple or very complex circuits. The trick in using those
testers in knowing how to interpret what you see on the CRT. The necessity
of having a schematic varies, depending on circuit complexity and your
skills. On a very complex circuit, especially one with lots of SMD
components, it's almost mandatory. On average, Huntron testers are
inexpensive when compared to state-of-the-art equipment from Agilent,
Tektronix, IET, etc. Some of those instruments can cost upwards of $100K.
The "bed of nails" fixtures are used with Automatic Test Equipment (ATE),
which is usually computer driven, and provides the necessary power and
signals to the circuit, measure the circuit's response to the applied
stimulus, and compare the response to specific limits. ATE systems require
all the necessary computer-driven (usually GPIB interface) test equipment
and a test program (software) that was written specifically for the
equipment being tested. It's not cheap (up to several million $$$$$). On
the flip side, ATE systems don't usually require an experienced tech to
repair a circuit. The ATE system tests the circuit, and if it fails a test,
the ATE tells the operator which components to replace. The operator
replaces the suspect components and retests the circuit to verify the
repair. ATE systems are also used to verify unpopulated circuit boards,
especially useful when they have multiple layers. Manual verification of a
PCB having hundreds of individual traces would be extremely time-consuming
and expensive.
No, these are not the only methods of troubleshooting circuits. If you have
the necessary signal generation equipment (analog and/or digital) and
response measurement equipment (scopes, meters, analyzers, etc.), you can
manually troubleshoot.even the most complex equipment. The more complex the
equipment, the more knowledge and expertise you will need.
There's really no substitute for a good knowledge of electronic theory and
the ability to use it when analyzing a misbehaving circuit.
--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in
the address)
Never take a laxative and a sleeping pill at the same time!! |
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