| 摘要 |
An electronic apparatus is constructed in the conventional modern (cheapest) way by utilizing one single large etch foiled circuit board with directly soldered in or pluggable (replaceable) chips incorporating micro-circuits. Each chip carries its own top side cold light emitting diode which is not energized during normal operation of the chip. Selected first and second pins of the various plurality of connecting pins for the chip may be temporarily short-circuited such as being touched with the tip of a screw driver. The chip is designed such that shorting of these first and second pins only will energize the light emitting diode only if the chip is good and there is power going to the circuit. Thus, part of each chip is a circuit analyzing (normally dormant) circuit. Determination of malfunctioning chips and replacement thereof is thus greatly simplified for the serviceman.
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