Electronics Forum: spots (Page 1 of 63)

White spots on PCB

Electronics Forum | Fri May 11 11:52:25 EDT 2001 | jagman

Does anyone know what would cause a PCB to develop white spots all over the board following parts placement and reflow? I need help!!

White spots on PCB

Electronics Forum | Sun May 13 21:02:34 EDT 2001 | djarvis

Gary, You're not trying to clean these boards with Iso or other solvents after using no-clean solder paste? That'll do it.

White spots on PCB

Electronics Forum | Mon May 14 19:16:49 EDT 2001 | jagman

Dave: Actually, I'm located in the South Bay (Santa Clara)! Good guess. Now, for more in-depth information: So far, the distribution has been limited to one board out of 10 assembled, so far from one lot. The components assembled are exclusively

White spots on PCB

Electronics Forum | Fri May 11 15:43:41 EDT 2001 | davef

More information would be helpful. For instance: * Talk about the distribution of the problem, including a single lot or from various lots and over components and component types on the board * Tell us about the board (ie, thickness, type, solder ma

White spots on PCB

Electronics Forum | Mon May 14 22:24:11 EDT 2001 | davef

The time over liquidous of the profile seems short. But then again, who knows? Based on what you told us, I'm guessing at a board fabrication problem, either measling or delamination. Probably the former, rather than the latter. [Now, we remember

SMD ceramic capacitors dark spots

Electronics Forum | Fri Jul 20 17:38:06 EDT 2018 | mikedcmt

We have some MLCC capacitors that show some discoloration, or spots. Does anyone know if this will affect reliability? Caps test good - and assemblies function perfectly.

SMD ceramic capacitors dark spots

Electronics Forum | Mon Jul 23 09:55:26 EDT 2018 | mgerrior

have not seen this issue personally, often identify cracks on MLCC parts but never dark spots. May be worthwhile to replace as a precaution if at all possible.

SMD ceramic capacitors dark spots

Electronics Forum | Mon Jul 23 10:56:38 EDT 2018 | dleeper

I've never seen this before and I would be suspicious. Have you tried to dust it off with a brush or Q-tip, it might just be some sort of process contamination. Have you looked at the reel to see if the parts are coming in with these spots from the

SMD ceramic capacitors dark spots

Electronics Forum | Mon Jul 23 11:02:56 EDT 2018 | mikedcmt

Thanks for your reply - parts in tape have similar markings - gets worse after reflow. ~20% have this issue. Units pass test no problem. Occurrence is random.

Non wetting spots of flex PCB pads

Electronics Forum | Fri May 12 19:42:05 EDT 2023 | emeto

Have you tried cleaning these spots with anything?

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