What is this yellow puppy? [Answered] - Page 1
Forum section: electronics / repair

author: max.wwwang
author_rank: Frequent Contributor
timestamp: June 17, 2023, 07:19:52 am
content: Repairing a computerized sewing machine (BERNINA ACTIVA 145), I came across this guy (yellow). Looks like a capacitor but not sure. And no idea of its value, whatever it is. Please help identify.Also I measured an (in-circuit) resistance of 2.8 Ohms between its two legs. If it is a capacitor, does this reading look suspicious? Thanks!

author: Xena E
author_rank: Frequent Contributor
timestamp: June 17, 2023, 07:56:35 am
content: Not sure 'what' it is...It certainly doesn't look as if it was a component added at assembly, if not a cap it could be a VDR maybe?Take it off the board and re-measure.Do you suspect a fault is being caused by this part?

author: jwet
author_rank: Frequent Contributor
timestamp: June 17, 2023, 08:03:02 am
content: Its a 100 mA "polyfuse" type device. The part number is RXEF010 I believe- Mfg is Littlefuse. They are self healing fuses that open on a fault, cool off and close again. Common in something like a motor drive where you'd be likely to overload something but don't want to pop a real fuse. Datasheet link:https://www.littelfuse.com/~/media/electronics/datasheets/resettable_ptcs/littelfuse_ptc_rline_catalog_datasheet.pdf.pdfGood luck.

author: max.wwwang
author_rank: Frequent Contributor
timestamp: June 17, 2023, 08:12:54 am
content: Quote from: jwet on June 17, 2023, 08:03:02 amThanks. This is very helpful! So it looks like the measurement means that it's ok.

author: max.wwwang
author_rank: Frequent Contributor
timestamp: June 17, 2023, 08:16:45 am
content: Quote from: Xena E on June 17, 2023, 07:56:35 amThanks. To be honest, I only hope it's faulty although I know the likelihood is very low that the fault of the machine is caused by it.

author: Gyro
author_rank: Super Contributor
timestamp: June 17, 2023, 09:05:48 am
content: Yes, that looks like mechanical damage from rough handling of the board, or careless insertion, rather than the cause of a fault. If it still reads right then your culprit probably lies elsewhere.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 17, 2023, 09:22:54 am
content: Not obvious too what or why, as far as what it's connected to.That package can be capacitor, MOV (VDR), occasionally some kinds of resistors (usually thermistors, NTC or PTC), or fuse (poly PTC). A capacitor that size and style might be around 100pF and used for EMI filtering or other high frequency related purposes. The others might be used for protection against excess voltage or current, perhaps for the nearby connectors; but those are rather unsubstantial connectors and it's not apparent whether that would even make sense.Quote from: jwet on June 17, 2023, 08:03:02 amHm, datasheet says marking is "X10", not "X010". 100mA would be a sensible rating if it's related to the nearby connectors. The logo is plausibly Raychem (now Littelfuse). (Or maybe it's the PolySwitch branding, I don't know; it's weird they don't put it in the datasheet?)Datasheet doesn't have a good picture, either; they typically look like this:https://www.parts-express.com/TE-Connectivity-Raychem-RXEF135-1.35A-Polyswitch-071-264?quantity=1The overlapping-double-V logo seems plausible here.Tim

author: Jwillis
author_rank: Super Contributor
timestamp: June 17, 2023, 03:21:13 pm
content: Quote from: T3sl4co1l on June 17, 2023, 09:22:54 amThe 60 is the Max voltage rating and the 010 is the current hold of 100mA , The over lapping V,s is the manufacture mark.https://www.digikey.ca/en/products/detail/littelfuse-inc/RXEF010/5015919If you look athttps://www.digikey.ca/en/products/detail/littelfuse-inc/RXEF040/5015989And zoom into the picture you'll see a 72V rating after Manufacture mark and a current hold 040(400mA) after series.https://www.digikey.ca/en/products/detail/littelfuse-inc/RUEF135/5016005Zoom in shows 30V rating after the manufacture mark and current hold 135(1.35A) after the seriesSome just show the voltage rating and some just have the manufactures mark. Guess the surface area just gets to small to give any other information.Polyswitch and Polyfuse are really the same thing just different trade marks series. But they are all Polymer PTC devices.

author: max.wwwang
author_rank: Frequent Contributor
timestamp: June 18, 2023, 12:25:28 am
content: Quote from: Gyro on June 17, 2023, 09:05:48 amYes, I agree. Although I desperately hoped it was the culprit (because of its look), it's now clear that it's ok electronically. The problem(s) certainly lie somewhere else.