A 3K9 1/4 watt resistor measures short cct.
Usual question:
Was it the last part de-soldered from the board?
It wasn't just the last, it was the last that could possibly BE desoldered from the faulty node.
I save these little miracles for some future gremlin exploit. Wonder, now, if that day will ever come . . . .
RL
Shorted MLCC (multi-layer ceramic capacitors) are more fun. If overheated, they tend to short circuit. If unevenly heated, they crack and become either an open, short or intermittent circuit. If DC is applied, they become a varactor. If I yell at the PCB, it becomes a microphone.
I don't believe in miracles, but I won't complain when a miracle solves my problem.
In my limited experience, SMD resistors can either become a short or an open circuit, depending on the phase of the moon (waxing or waning).
Yeah, but an AXIAL 3K9 1/4W?
I don't know how far down a troubleshooting tree that falls.
I'm pretty sure it doesn't even show up, on mine.
RL
I was a tech for the largest consumer electronics chain in the U.S and then at high end audio video store. Next a maintenance engineer in a television studio. All together, 46 years servicing various electronics devices and I never saw a shorted axial resistor.
Carbon film? Carbon comp? Metal film? Wirewound? Metal oxide? 2H pencil? etc
I've seen really strange resistor failures, but none that I can recall were shorted. Usually, something causes the resistor to become hot which eventually produces an open circuit. Very rare, methinks. The only "shorts" I've seen were with mismarked (color coded) resistors.
I perform troubleshooting by shooting the guy who's giving me trouble. Hanging him from a tree might work, but having him fall from a great height might be equally effective. How far or how high? I don't know.
Do you really have a hanging (or falling) tree? Very convenient for disposing of troublesome individuals.
Mmmh. At one time, I had the surprise that the voltage setting feedback resistors around an LM317 regulator changed value by a large percentage. These were ordinary 1% 1/4W axial leaded metal film resistors. I never found out how or why this happened.
The box was in a radioactive zone, but no other components were affected and resistors can handle radiation much better than semiconductors anyway.
Jeroen Belleman
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