Need Help Identifying SMD Components on Bosch Oven Control Board - Page 1
Forum section: electronics / repair

author: hysti.rese
author_rank: Newbie
timestamp: December 30, 2023, 05:15:47 pm
content: Hello everyone,I'm working on troubleshooting an issue with a Bosch steam oven, model HRG636XS6. The control board, produced by DIEHL with the device number 9001055783, has two damaged SMD components marked "18L0". These components were affected due to an incorrect current measurement process using a multimeter, leading to overheating and an arc. They are small, black, elongated, and have two contacts, located in a part of the board related to the motors controlling the water tank flap.Interestingly, the oven continues to function normally for regular baking. However, when the steam function is activated, the oven immediately terminates the program and displays an E6400 error, which suggests a fault with the motors of the water tank flap. I suspect these "18L0" components might be fuses related to this part of the circuit.I'm looking for assistance in identifying these components to find the right replacements. Here's what I need help with:Interpretation of the "18L0" code for component specifications (current rating, voltage rating, etc.).Methods or resources for identifying such components based on their markings, especially in the context of a Bosch HRG636XS6 oven's control board.Suggestions for sourcing appropriate replacement parts to resolve the E6400 error and restore full functionality to the oven.Any insights, experiences, or resources you could share would be greatly appreciated. My goal is to accurately replace these components and address the E6400 error while ensuring the safety and functionality of the oven.Thank you in advance for your expertise and assistance!

author: fzabkar
author_rank: Super Contributor
timestamp: December 30, 2023, 05:31:35 pm
content: What is on the underside of the PCB corresponding to the "stain"?

author: SeanB
author_rank: Super Contributor
timestamp: December 30, 2023, 05:43:53 pm
content: Looks like is was a small Y2 ceramic capacitor, similar to the one on the lower left, the shiny blue one. Or it was a 275V MOV, similar in size, used as surge arrestor. The 2 SMD resistors, 18L0, should measure under 20 ohms, roughly 18R, and probably is a fusible resistor.

author: fzabkar
author_rank: Super Contributor
timestamp: December 30, 2023, 06:13:58 pm
content: https://schraub-doc.de/media/catalog/product/cache/f4127244fe84412a719e678491704f25/f/e/fe6cc57efd7e31c02d242f2241c9a578.jpeg

author: hysti.rese
author_rank: Newbie
timestamp: December 30, 2023, 09:36:14 pm
content: Thank you for your prompt responses.@fzabkar: I neglected to take a photo of the underside of the board. However, to the best of my recollection, there were no components soldered on the back side. The soldered ring structures were visible from this side, though. Additionally, it might be worth noting that there is a slit under both of the "18L0" components, possibly for enhanced heat distribution. The image you located at schraub-doc.de is indeed the exact board I have.@SeanB: Just to clarify and avoid any confusion – there are no parts missing on the board. My query concerns those two small black SMD parts labeled "18L0". Are you certain these are intended to be resistors? Is "L0" a common naming scheme instead of "R0"?Thank you all for your assistance thus far, and I wish you a great start to the new year.

author: fzabkar
author_rank: Super Contributor
timestamp: December 31, 2023, 03:25:59 am
content: I would trace the circuit in that area, otherwise I don't know how to make sense of that "stain".

author: gamalot
author_rank: Super Contributor
timestamp: December 31, 2023, 06:06:16 am
content: They are 18 milliohm metal strip low ohm chip resistors.

author: gamalot
author_rank: Super Contributor
timestamp: December 31, 2023, 06:08:46 am
content: https://www.rohm.com/products/resistors#searchbyspecification

author: bingo600
author_rank: Super Contributor
timestamp: December 31, 2023, 06:57:04 am
content: Is that a resistor , besides the "Big blue squared cap" , below the orange wire ??Looks like the coloring is gone ... (toasted ?)