Ripped solder pads  - Page 1
Forum section: electronics / beginners

author: zupta82
author_rank: Regular Contributor
timestamp: January 02, 2021, 08:49:40 pm
content: Hello everyone and happy new year. I managed to rip up some solder pads. I traced the pads and the central node at the pad was in series with the eyelet hole that connected to the multiple separate layers of the board. It’s kind of hard to explain, it seems the pads were there for anchoring the component rather than a signal path. This has always confused me with circuit boards. It wasn’t a surface trace where if you took an xacto knife and sliced thru the trace you would effectively eliminate the signal flow. This is the reason when why I did not use any jumper wires. I figured the connection was made by the solder that flows into the joint

author: ataradov
author_rank: Super Contributor
timestamp: January 02, 2021, 09:15:36 pm
content: Do you have pictures or something to better explain the issue?

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 02, 2021, 09:50:49 pm
content: Quote from: zupta82 on January 02, 2021, 08:49:40 pmDesigners can make a metallized hole through for mounting only, so often happens. But we can not exclude that any inner layer will use it as a signal. A slightly complicated operation to restore metallization requires some skill and a microscope, at a minimum. There are a lot of videos on youtube about this.

author: zupta82
author_rank: Regular Contributor
timestamp: January 03, 2021, 02:07:11 am
content: Here is a pic with intense light thru the board

author: zupta82
author_rank: Regular Contributor
timestamp: January 03, 2021, 02:09:10 am
content: Sorry I forgot to attach.

author: zupta82
author_rank: Regular Contributor
timestamp: January 03, 2021, 02:13:03 am
content: The ripped pads are the heatsinked power mosfets

author: ataradov
author_rank: Super Contributor
timestamp: January 03, 2021, 02:14:39 am
content: It is not clear what exactly is wrong. Do you have a close up picture of the actual damage?

author: zupta82
author_rank: Regular Contributor
timestamp: January 03, 2021, 02:47:51 am
content: Here is a close up pic

author: WattsThat
author_rank: Frequent Contributor
timestamp: January 03, 2021, 02:55:14 am
content: Ok, it’s time to use a photo editor and put a red circle around the area that you are referring to.Or an arrow or something, anything.Edit: if it’s the single round pad to the right of the brass nut on the stud, that’s a plated though hole. The trace is on the other side of the board. Hopefully it’s not a four layer board.

author: WattsThat
author_rank: Frequent Contributor
timestamp: January 03, 2021, 03:02:36 am
content: Cannot correlate the top to the bottom of the board. Could you please highlight (circle, arrow, anything) and mark the corresponding lead on the top view of the board? The photo used in reply #5 should be a good starting point.

author: ataradov
author_rank: Super Contributor
timestamp: January 03, 2021, 03:32:33 am
content: It appears that you mean annular rings that came off. If the other side of the board has a good soldered connection, then it is probably fine, especially if the board and the device will be mechanically fixed with a heatsink.The board seems to be double sided, so there are no internal layers to worry about.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 03, 2021, 10:51:37 am
content: Don't worry about torn pads, they are not used, the connection is on the other side.

author: Refrigerator
author_rank: Super Contributor
timestamp: January 03, 2021, 11:32:45 am
content: Personally i'd worry more about cleaing the board up because it seems a little dirty.Those pads are just a part of the process when producing through holes in double sided PCB's.The connection is available on both sides of the board so the designer is free to use whichever layer they prefer to make the connection.In this case i think the bigger question is how did the pad even come off?

author: zupta82
author_rank: Regular Contributor
timestamp: January 03, 2021, 06:32:21 pm
content: Here are some pics with marker highlighted circled areas that indicate torn pads. Also the numbers correspond to actual component. As well I pointed with an arrow on the component side to one pad that I had to heat up to remove one really stubborn lead. I can’t seem to upload all the pics in one reply

author: zupta82
author_rank: Regular Contributor
timestamp: January 03, 2021, 06:34:23 pm
content: Here is the second pic

author: zupta82
author_rank: Regular Contributor
timestamp: January 03, 2021, 06:35:14 pm
content: Here is the third

author: zupta82
author_rank: Regular Contributor
timestamp: January 03, 2021, 06:37:12 pm
content: Here is the one pad on the component side

author: ataradov
author_rank: Super Contributor
timestamp: January 03, 2021, 06:39:06 pm
content: The ripped pads are not that much of a problem. But actual soldering is horrible here.Forget about the pads, but make sure to properly reflow the solder joints in places there pins to to the real traces. Use flux. And remove the dirt before you do this.

author: zupta82
author_rank: Regular Contributor
timestamp: January 03, 2021, 06:56:33 pm
content: Let me explain, I previously installed two ultra fast recovery diodes and 8 mosfets. The soldering was initaially good, I went back and removed the solder to better see the pads that I was going to prepare for these recent pictures. The board is dirty due to this oil based conformal coating that I could not remove when I first messed with project so I flowed solder until some of this coating boil and float out of liquid solder. It almost smelled like solder flux

author: ataradov
author_rank: Super Contributor
timestamp: January 03, 2021, 07:01:21 pm
content: In the end, it is a two layer board. The only place good connection matters is where the part connects to the trace. If that happens on one side and the other side just have the annular ring, then the ring does not matter.

author: zupta82
author_rank: Regular Contributor
timestamp: January 03, 2021, 07:04:33 pm
content: I’ve forgot to mention. I always remove conformal coating before I solder, I don’t want to expose myself to the nasty toxic burned conformal coating smell. I had no choice the first time around which caused me to rip a bunch of pads off in the process and by picking I would have damaged the board further, I was thinking this is why I could not get this thing to work correctly.

author: zupta82
author_rank: Regular Contributor
timestamp: January 03, 2021, 07:21:40 pm
content: It probably wouldn’t hurt to run some jumpers or ohm out the areas that I messed up before I reassemble. I can’t really test this thing live due to the high current and high voltage