Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Help with damaged board

eddiewink

Newbie
Joined
Apr 13, 2021
Messages
4
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
40
Hello, wondering if anyone could help me out here. I don't work with PCBs, but troubleshooting a salt chlorine generator for my pool and believe the board in the pics below is the cause. My question is, does the level of corrosion shown seem like something i can clean with isopropyl alcohol and a toothbrush? I won't even bother trying to remove the damaged components and replace, I've never soldered anything before in my life and I'm sure I'd do a horrible job.

The part isn't easily replaceable as it is no longer manufactured by the vendor so trying to salvage if I can before spending thousands on a new system.

Thanks for any help you can provide.

Images:
Eddie
 

betwixt

Super Moderator
Staff member
Joined
Jul 4, 2009
Messages
14,866
Helped
4,857
Reputation
9,732
Reaction score
4,640
Trophy points
1,393
Location
Aberdyfi, West Wales, UK
Activity points
126,540
Should be easy to repair.

If the corrosion is primarily from salt, wash it in warm water first, salt may not dissolve in alcohol. Let it thoroughly dry then give it the brush and alcohol treatment.
All the components are encased in resin of some type so they have probably survived, the copper tracks on the board may have corroded right through and gone open circuit through. If any have, you can wire across the ends of the tracks to restore the connection, it won't look neat but it does the job.

Brian.
 

eddiewink

Newbie
Joined
Apr 13, 2021
Messages
4
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
40
Thanks for the feedback Brian. Any chance I can go to complete noobie question and ask how I'd know if the corrosion went all the way through and on which components? Just a multimeter over the two contacts for example on each resistor?

For the wiring, I don't care what it looks like, but just want to understand. I'd basically take a light gauge wire and solder one end to each side of the resistor using the same example if that is the broken path found?
 

betwixt

Super Moderator
Staff member
Joined
Jul 4, 2009
Messages
14,866
Helped
4,857
Reputation
9,732
Reaction score
4,640
Trophy points
1,393
Location
Aberdyfi, West Wales, UK
Activity points
126,540
Almost right.
The copper traces on the board are what connects the components together, they are the 'wires' if it was built without a board. You should have close to zero ohms between each component connected to the SAME track. You might get readings across components or from one track to another but the resistance would be higher. So if you take each track in turn, place a probe on one end and check all the other places that track visits with the other probe, you should get almost zero ohms reading. By 'almost zero' I mean probably less than about 5 Ohms, there is always some residual resistance in any copper track and in the meter probes themselves but typically a broken track will read hundreds or thousands of ohms from one end to the other. If you find a break there will usually be some visible corrosion where the copper has been eaten away. Find the closest two component pads along the rack that has the break between them and solder a bridge between them. Use thin insulated wire because you might find some of the bridges cross over each other and you don't want them to touch.

Use a test meter to check the tracks, under no circumstances use a battery/lamp circuit to check for continuity because the power they use will damage some of the components.

Brian.
 

eddiewink

Newbie
Joined
Apr 13, 2021
Messages
4
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
40
Ah got it, I completely misread but that makes total sense. Thanks again especially for all the extra testing guidance, now to get my multimeter back from my brother-in-law and get started!
 

KlausST

Super Moderator
Staff member
Joined
Apr 17, 2014
Messages
19,462
Helped
4,304
Reputation
8,613
Reaction score
4,260
Trophy points
1,393
Activity points
129,071
Hi,

I see nothing on the board photos that is critical to be washed.
I guess that the corrosion is not caused by simple salt, but by (residuals of) HCl.
It may be washed with light alkaline solution to get rid of acid residuals. Use a soft brush. Be mechanically careful.
After that wash it clean with clear water, or if you have: demineralized water.
If you have use compressed air to get it dry, be sure to blow out water underneath the parts.

I'd replace the pushbuttons.

Klaus
 

eddiewink

Newbie
Joined
Apr 13, 2021
Messages
4
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
40
Thanks Klaus, appreciate the additional feedback!

Really appreciate both of you helping out, I know this forum is meant for things far greater than my complete lack of knowledge but hopefully saving me a couple thousand dollars with this potential fix!
 

LaTeX Commands Quick-Menu:

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top