Weird resistor color code

Subscribe to Thread

Hello there! In one SMPS, I noticed a blown resistor with th... - Nov 22, 2021 by zxcvb

You say the resistor is blown. Is the body discolored? Is i... - Nov 22, 2021 by ProcEng1

Are they all evenly spaced? If that first gold is orange and... - Nov 22, 2021 by Stephen

zxcvb

#87321

Weird resistor color code | 22 November, 2021

Hello there! In one SMPS, I noticed a blown resistor with the following color code: yellow (4) Violet(7) Gold(?) Gold Black. I'm not sure what the value is. The dimensions of the resistor are those of a conventional MF0207 metal film resistor. I assume it's a fusible resistor in series with the ferrite transformer's primary, with a TinySwitch TNY268 on the opposite side. What is the value of the primary resistor? I've read some articles like this (https://www.apogeeweb.net/electron/a-guide-to-color-code-of-resistor.html), but I still have no idea.

reply »

ProcEng1

#87323

Weird resistor color code | 22 November, 2021

You say the resistor is blown. Is the body discolored? Is it possible that these are not the colors, like maybe the first GOLD is actually orange? Perhaps post a photo?

reply »

Stephen

#87327

Weird resistor color code | 22 November, 2021

Are they all evenly spaced? If that first gold is orange and the black is spaced farther apart than the others then it could a polarity band or not really a band. Don't know why a resistor would have one.

If that is the case then it is a 47K 5%. Which sounds large for the circuit you described.

I just found this page but for the five band resistors it doesn't have black as the fifth band. https://www.allaboutcircuits.com/tools/resistor-color-code-calculator/ If the last band is grey then it is a 47.3Ohm 0.05% resistor

reply »