this post was submitted on 09 Jul 2026
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I'm currently repairing a device and I'm trying to understand what this circuit board does and how, and whether it is causing the malfunction. While doing that I stumbled upon this resistor whose color code does not agree with my multimeter. I'm measuring 152.1Ω, but the way I'm reading the colors it should be the very common value of 69.1MΩ. If I reverse the order, I get 1.51Ω/15.1GΩ/151GΩ, depending on whether the second color from the left is silver, grey or white. Black would give me 151Ω, but it definitely is not black.

The device this circuit board is from is pretty old. I don't know how old, but there is exactly one IC on it, with a datasheet published in April 1974. The relay in the background has 1979 written on it; I'm not sure if that is supposed to be a year.

Any ideas? Am I reading the colors wrong? Do I trust the multimeter or the markings regarding the intended value of this resistor? Have you seen resistors whose color codes have changed over decades of use?

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[–] Treczoks@lemmy.world 16 points 22 hours ago

Not necessarily the color code that changed. Even though resistors are resilient, they may fail and change their value. Given that the device is 50 years old, it might happen.