How do i find a replacement for this surface mount component - Page 1
Forum section: electronics / beginners

author: rusty_uk
author_rank: Newbie
timestamp: September 26, 2023, 06:17:36 pm
content: HiI found a damaged component on a board that im trying to fix. I believe that it is a cap since the label nearest suggests that it is C62. I get no reading when i test the device other than an open circuit.Im not sure what i would replace this component with since I have no idea of it's value.Are these standard value devices? If so can i just replace with something similar?Is this indeed a cap?Images of the device are as follows:

author: u666sa
author_rank: Frequent Contributor
timestamp: September 26, 2023, 06:39:29 pm
content: What kind of board is this? Zommed out photo plz

author: Doctorandus_P
author_rank: Super Contributor
timestamp: September 26, 2023, 06:48:43 pm
content: That very likely was a capacitor. But those things can be roughly between 10pF and 10uF, which is 6 orders of magnitude difference, and you can't just put some random value.You can reverse-engineer a part of the design around the capacitor, and from that determine what it sort of is, or at least find a workable substitute, but you need some electronics knowledge and experience for that.

author: DavidAlfa
author_rank: Super Contributor
timestamp: September 26, 2023, 07:01:06 pm
content: 100% a cap.Thick trace, dark color, other caps in parallel, seems a simple decoupling cap, I don't think the value is critical as long as it's 1uf+.Will probably work just fine without it.

author: rusty_uk
author_rank: Newbie
timestamp: September 26, 2023, 07:51:08 pm
content: Full board image. The cap was removed from the bottom Right. Is this helpful?

author: rusty_uk
author_rank: Newbie
timestamp: September 26, 2023, 07:56:02 pm
content: Added a little red box to it's location this time.Slightly concerned about the conflicting answers though. If i just pop a 1uf cap in it's place as suggested by DavidAlfa is it likely to trash the thing? As Doctorandus_P mentioned, there is a wide variance between the smallest and largest cap rating

author: u666sa
author_rank: Frequent Contributor
timestamp: September 26, 2023, 08:00:28 pm
content: Appears to be part of power circuit. Perhaps your board will work fine without it. If not, try to draw a circuit.

author: BrokenYugo
author_rank: Super Contributor
timestamp: September 26, 2023, 08:22:50 pm
content: It is typical "rule of thumb" sort of design to massively over filter power rails, decouple ICs at every package, etc. to stay out of the sort of trouble not doing that (weird intermittent glitches) leads to. Any fairly high value ceramic will be better than nothing in restoring the design intent of that part of the circuit, no capacitor you can fit in there will "trash the thing" provided you install it correctly.I would have no hesitation attempting to power that board up with the fried cap removed after double checking it's just across some power rail (buzz it out with a multimeter, confirm parallel connection to a nearby electolytic), those multi layer ceramic caps can fracture and short, likely all that went wrong, and likely it'll run about forever with it gone. If it bugs you 1+uF is a solid estimate, the actual capacity of a MLCC is a sort of hard thing to define anyhow, they lose capacity with DC bias.

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: September 27, 2023, 07:33:56 am
content: Try an ordinary wire ended cap, they are easier to add/remove on a temporary basis. Surface mount caps like the one you removed are not marked with a value, so it's just a complete guess as to what value it was. Try a 100nF as it looks to be around a regulator/supply smoothing area.SJ

author: Doctorandus_P
author_rank: Super Contributor
timestamp: September 27, 2023, 07:43:56 am
content: Quote from: BrokenYugo on September 26, 2023, 08:22:50 pmBut that goes back to the first post I made about reverse engineering that part of the schematic. It may also be a capacitor that determines oscillations frequency or some compensation for the SMPS. And if that is so, then having a look at the datasheet of the IC's used very likely gives you a good suggestion for what value it should be.

author: Terry Bites
author_rank: Super Contributor
timestamp: September 27, 2023, 06:41:32 pm
content: I agree with the majority view that its a cap.It doesn't look like there are any timing components nearby so chuck in a 50V 100n and see what happens.Was it blown by an over voltage do you think?