STAR*TECH JOURNAL/MARCH 1983
7
BUGTRAP
SIGNATURE ANALYSIS
As manufacturers have become more responsive to the needs of the service
industry, various test procedures for microprocessor-based equipment have
been developed. None of these techniques, however, have proven to be as
simple and reliable as signature analysis, a technique patented by and
licensed from Hewlett-Packard.
The Bugtrap Signature Analyzer, utilizing industry standard signature
analysis design, processes digital bit streams to produce a four-digit,
hexadecimal "signature". Each node or test point in a circuit will have one
of over 65,000 possible signatures. By using manufacturer supplied
documentation for testing, test points can be probed in an orderly fashion.
An incorrect signature will identify the failure down to the component level,
including such complex components as PROMs, ROMs, RAMs, and
microprocessors. Signature analysis allows for the testing of these com-
ponents in circuit at full system speed. This technique has allowed
troubleshooting of complex digital systems with a minimum of experience.
Once an understanding of the signature analysis technique has been
achieved, it is possible to produce and document signatures for equipment
not provided with manufacturer documentation.
Because of the rapid pace that new microprocessor-based equipment is
introduced to the marketplace, it is unreasonable to expect service technicians
to become thoroughly familiar with one particular item. Signature analysis
has been acknowledged by manufacturers in growing numbers as the
solution to this problem. With its universal digital applications, a signature
analyzer can take the place of many pieces of expensive test equipment and
individual test fixtures.
Bugtrap Instrumentation in Sunnyvale, California has a reputation for
building rugged, reliable test equipment that is equally at home in the field as
it is on the bench. By keeping its practical use in mind and utilizing the latest
technology, they have produced what they feel to be the most usable
signature analyzer on the market today. It is small, draws its power from the
unit under test (5vdc with low current requirements), and is easy to use. At
less than half the price of comparable units, the Bugtrap Signature Analyzer
has proven its cost effectiveness, even for low volume repair requirements.
SPECIFICATIONS
Display:
Signature: four-digit hexadecimal; characters 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, C,
F,H,P, U.
Clock: panel light-indicates clock activity when on or blinking.
Data: panel light - indicates data activity when on or blinking.
Gate: panel light- indicates that instrument is acquiring signatures when lit.
Probability of Classifying Correct Data Stream as Correct:
100%
Probability of Classifying Faulty Data Stream as Faulty:
99.998%.
Data Probe:
Loading: less than ½ TTL load.
Set-up time: 15 nanoseconds (data must be valid at least 15 nanoseconds
prior to selected clock edge).
Hold time: 0 nanoseconds ( data must be valid until occurrence of selected
clock edge.
Gating Control Lines:
Loading: less than ½ TTL load.
Set-up time (Start/Stop): 15 nanoseconds (signals must be valid at least 15
nanoseconds prior to selected clock edge).
Clock: 10 MHz.
Overvoltage Protection:
Start, Stop, Clock: 20vdc.
Data: diode clamped to VCC and GND.
VCC, GND: regulated and reverse voltage protected.
Power Requirements:
+ 5vdc ( ± .25 vdc) at less than 400 milliamps ( derived from unit under test).
Dimensions:
135 mm. x 102 mm. x 38 mm. (5.3 in. x 4.0 in. x 1.5 in.)
Enclosure:
High impact, ABS thermoplastic (non-conductive).
For further information, please contact Bugtrap Instrumentation, 1173
Tasman Drive, Sunnyvale, CA 94086. 408/734-1118.
SERVICE.
Bally Midway believes that it's our responsibility to make
your job easier. We keep your service needs in mind beginning
with our games's initial designs.
A history of conducting the industry's first service schools
is continued today through our distributors, holding service
schools all over the world. Our service manuals are specifi-
cally designed to simplify repairs and are packed in every
pin or video game we ship, saving you unnecessary time
and money locating one.
Star-Tech's reader survey speaks for us: Bally Midway is
among the leaders in service.
Get our service newsletter! Call Bally Midway's toll-free
service number: 1-800-323-7182.