Resistor identification - Page 1
Forum section: electronics / projects

author: xuio
author_rank: Contributor
timestamp: August 26, 2015, 03:11:01 pm
content: I need to replace a broken resistor. (see photo, brown red brown red [silver?])Candidates are: 120, 12k Ohm. (I don't care about the tolerance)How can I be shure if I need to use the four or five ring table? (the fith ring is not clearly visible)Thanks for your help,MoritzEDIT: Okay, I think it's a five-ring one (b r b r silver) because of the symmetry

author: TheElectricChicken
author_rank: Frequent Contributor
timestamp: August 26, 2015, 03:40:19 pm
content: do you have anything about the circuit as well ? that can give a great many clues as well.... the function would give away how much it should be as well as good eyesight.if no-one gives you a convincing guess, go the photos of the board both sides, straight above the parts especially.

author: TheElectricChicken
author_rank: Frequent Contributor
timestamp: August 26, 2015, 03:42:10 pm
content: Cannot tell for sure, so post some pics of the board. please place the broken resistor next to other resistors when you take the pic, because the comparison amongst colors will help heaps.

author: SeanB
author_rank: Super Contributor
timestamp: August 26, 2015, 06:02:17 pm
content: With the green background and the shape are you sure it is not an inductor or a capacitor?

author: xuio
author_rank: Contributor
timestamp: August 26, 2015, 06:26:55 pm
content: It's part of a dashboard assembly from an old BMW car.It was damaged by battery acid.The resistor sits right next to a chip. (see attachment)I'm pretty shure it's a resistor, there are many of this style on the board. There are also no caps and thick traces nearby.Moritz

author: TheElectricChicken
author_rank: Frequent Contributor
timestamp: August 26, 2015, 06:53:14 pm
content: that is an excellent image and shows it a great deal better. it's possible to see what it looked like and make a better guess. I might not guess on this one as i am not 100% certain yet, someone else may guess first. The other thing is, can you choose the part of the board that has the biggest collection of resistors and put it next to those ones. it's possible at the moment to compare the colors and the color bands to those other three on the board, though, if nobody can make a confident guess, more resistors will help. It could very well have passed for an inductor before, it did look like one, but in context it seems less so.

author: TheElectricChicken
author_rank: Frequent Contributor
timestamp: August 26, 2015, 06:56:09 pm
content: I would say brown red orange red, but it is too close to call. Other side of resistor please !

author: xuio
author_rank: Contributor
timestamp: August 26, 2015, 07:04:56 pm
content: Quote from: TheElectricChicken on August 26, 2015, 06:56:09 pmHere are some more pictures: (Google drive because better quality [scroll to zoom])https://drive.google.com/folderview?id=0Byutz5-RAoHifmFMWEVaUUItM29ySVVXZV9Yb180eE1RdGZrV1JIcUx5QTd4M0VNZEJqcUE&usp=sharingThanks!Moritz

author: SuperJeep
author_rank: Contributor
timestamp: August 26, 2015, 07:14:49 pm
content: Hello,I tried looking for the part number of that chip and found nothing but I got results for a switching regulator calledMZC3001 DIP 18PIN (same package and 3001 might be same chip but different manufacturer?)If you look at a schematic example given here:http://s3.amazonaws.com/f01.justanswer.com/needanswers007/2011-12-19_045612_ic6501_skematic.jpgwe can see that in the schematic, pin 5 goes to ground and in your pictures, pin 5 of that chip also makes it to a screw terminal/guessing groundI can also see that pin 11(ground in the schematic) which is a ground for a p-channel device (mosfet/transistor) is going to what looks like a t0-92 packaged transistor?Im taking wild guesses here but if that is the case, then that blown resistor might be the resistor connecting to pin 4 which is part of an RC circuitthat sets the chips switching frequency(valued at 13k in that schematic (also note the very close, small value capacitor which is connected to ground and what could possibly be the CT in the schematic)DISCLAIMER: Im taking wild guesses in saying that is the same IC as what you have there, hopefully this helps lead toward a solution though!EDIT: Sorry for all the edits, I type before I think

author: TheElectricChicken
author_rank: Frequent Contributor
timestamp: August 26, 2015, 07:21:07 pm
content: The colors are still such a tough one. this is the best puzzle yet for color, oh kiss the hands of the maker of the ohmmeter, it is a godsend to me these days. SuperJeep has done the work on the circuit side, and THAT will be the solution for this case. Someone will read the datasheet and check that I figure. There are no green bodied resistors on that board with distinctive orange bands. There are red and brown on green bodies though.

author: TheElectricChicken
author_rank: Frequent Contributor
timestamp: August 26, 2015, 07:24:36 pm
content: from the circuit I'm 95% sure it will be 12k.

author: xuio
author_rank: Contributor
timestamp: August 26, 2015, 07:39:14 pm
content: Quote from: TheElectricChicken on August 26, 2015, 07:24:36 pmQuote from: SuperJeep on August 26, 2015, 07:14:49 pmThank you!I'll go with 12kMoritz

author: TheElectricChicken
author_rank: Frequent Contributor
timestamp: August 26, 2015, 09:30:45 pm
content: Quote from: xuio on August 26, 2015, 07:39:14 pmyou're welcome.please do let us know how it goes !!!