Anyone know of a way to repair pitted contacts on a smart watch?

[Kawaii Koneko]

So the contracts on the four little circular contracts on the back of my Hauwei Watch 2 Classic have become pitted. It is like the metal has slowly been eaten away over time. I'm pretty sure that is the problem as they appear visibility cratered and before the watch stopped charging altogether, it would charge if I pressed hard. Now I can't get any response. I tried cleaning them with isopropyl alcohol but yeah, it's clear it is an issue of material being scratched off over time.

 

Is there anything I can do short of replacing the back cover? I can get the back covers for like 20 bucks on eBay but all I can find are silver ones (I have black) and they will take like a month to arrive from China!

 

I remember watching a retro computer video where they restored the contracts on a keyboard with a special concoction that they used to basically fill in the kind of metal that had worn off. Maybe the same thing is possible with this?

[W-L]

7 minutes ago, Kawaii Koneko said:

So the contracts on the four little circular contracts on the back of my Hauwei Watch 2 Classic have become pitted. It is like the metal has slowly been eaten away over time. I'm pretty sure that is the problem as they appear visibility cratered and before the watch stopped charging altogether, it would charge if I pressed hard. Now I can't get any response. I tried cleaning them with isopropyl alcohol but yeah, it's clear it is an issue of material being scratched off over time.

 

Is there anything I can do short of replacing the back cover? I can get the back covers for like 20 bucks on eBay but all I can find are silver ones (I have black) and they will take like a month to arrive from China!

 

I remember watching a retro computer video where they restored the contracts on a keyboard with a special concoction that they used to basically fill in the kind of metal that had worn off. Maybe the same thing is possible with this?

Can you take a photo of it? If the material is corroded away you would need to rebuilt the loss, the only way to do so would be to add something like solder but that corrosion would still occur since it's a soft metal. 

[Kawaii Koneko]

43 minutes ago, W-L said:

Can you take a photo of it? If the material is corroded away you would need to rebuilt the loss, the only way to do so would be to add something like solder but that corrosion would still occur since it's a soft metal. 

Sorry for the crap photo, my hands were just too shaky and I was using my old phone because my other one is charging downstairs.

[W-L]

19 minutes ago, Kawaii Koneko said:

Sorry for the crap photo, my hands were just too shaky and I was using my old phone because my other one is charging downstairs.

Oh wow that's experienced a lot of wear, that could be attributed to the contacts being a very soft material compared to the pins or contact arcing when the pins make contact slowly eroding away the material. Soldering those contacts would work but only temporarily and will most likely wear very quickly once again.  

 

They make electrically conductive epoxy/metallic pens which may work to repair it, most likely it will need some touch up overtime. 

 

https://www.mgchemicals.com/products/adhesives/electrically-conductive-adhesives/two-part-epoxy/silver-conductive-epoxy-8331

https://www.mgchemicals.com/products/prototyping-and-circuit-repair/conductive-pens/841ar-p-nickel-conductive-pen

 

 

-Moved to Hobby Electronics- 

[Kawaii Koneko]

1 hour ago, W-L said:

Oh wow that's experienced a lot of wear, that could be attributed to the contacts being a very soft material compared to the pins or contact arcing when the pins make contact slowly eroding away the material. Soldering those contacts would work but only temporarily and will most likely wear very quickly once again.  

 

They make electrically conductive epoxy/metallic pens which may work to repair it, most likely it will need some touch up overtime. 

 

https://www.mgchemicals.com/products/adhesives/electrically-conductive-adhesives/two-part-epoxy/silver-conductive-epoxy-8331

https://www.mgchemicals.com/products/prototyping-and-circuit-repair/conductive-pens/841ar-p-nickel-conductive-pen

 

 

-Moved to Hobby Electronics- 

Okay, thanks a lot! I'm going to order the second pen you linked me to. As as long as it works, I'm fine with having to occasionally touch it up. 

[boarder2k7]

I strongly doubt this is from arcing, the currents involved in charging a smartwatch are way too low for that. A 300 mAh battery in a 3 hour charge is only 100 mA which just isn't enough to cause significant pitting.

 

This damage is typically caused by the super thin plating they use to keep the contacts from corroding getting worn off by the charging contacts, then the salt in your sweat attacks the contacts and pits them.

 

This same thing happened to my first gen Galaxy Watch or whatever they called it. I was fortunately able to find a repair part from some obscure Chinese website, open the watch up, and replace the part, it was a separate sub assembly glued in from the back of the case, which also looks to be the case here.

 

There isn't any harm in trying a conductive pen, just make sure not to bridge anything. I think your only real long term solution is to find a repair part though.

[ColinLTT]

21 hours ago, boarder2k7 said:

I strongly doubt this is from arcing, the currents involved in charging a smartwatch are way too low for that. A 300 mAh battery in a 3 hour charge is only 100 mA which just isn't enough to cause significant pitting.

 

This damage is typically caused by the super thin plating they use to keep the contacts from corroding getting worn off by the charging contacts, then the salt in your sweat attacks the contacts and pits them.

 

This same thing happened to my first gen Galaxy Watch or whatever they called it. I was fortunately able to find a repair part from some obscure Chinese website, open the watch up, and replace the part, it was a separate sub assembly glued in from the back of the case, which also looks to be the case here.

 

There isn't any harm in trying a conductive pen, just make sure not to bridge anything. I think your only real long term solution is to find a repair part though.

Echoing this - Looks like electrolytic wear. The salt in your sweat creates a galvanic cell between the charging contacts and the base, and the anode (weaker metal) erodes. Just like how boats and crab pots have a sacrificial block of zinc to keep them from eroding into the sea. 

 

A pen --might-- work, but I doubt it. Be sure to report back! 

[iBabySlapper]

On 5/5/2020 at 12:57 AM, Kawaii Koneko said:

Okay, thanks a lot! I'm going to order the second pen you linked me to. As as long as it works, I'm fine with having to occasionally touch it up. 

I wouldn't personally go with this, you might give yourself minor nickel poisoning... But oh well, what's life without some element of danger. It's better than tinning the contacts and getting lead poisoning.

[boarder2k7]

5 hours ago, iBabySlapper said:

I wouldn't personally go with this, you might give yourself minor nickel poisoning... But oh well, what's life without some element of danger. It's better than tinning the contacts and getting lead poisoning.

As someone who worked for a year running board and wiring assembly with leaded solder, I can tell you that the talk of issues from leaded solder is highly overblown. I went through a LOT of solder, over a pound a month of Kester 60/40, and when I left that job I had my doctor run lead levels in my next routine blood work, and there was nothing detectable. Just wash your hands/don't lick the lead and you'll be just fine. The ROHS solder is arguably worse for you because the flux fumes are considerably harsher and pose more of an inhalation hazard.

 

Nickel is a common component in jewelry, so I'm pretty sure that's a non-issue.

[iBabySlapper]

1 minute ago, boarder2k7 said:

As someone who worked for a year running board and wiring assembly with leaded solder, I can tell you that the talk of issues from leaded solder is highly overblown. I went through a LOT of solder, over a pound a month of Kester 60/40, and when I left that job I had my doctor run lead levels in my next routine blood work, and there was nothing detectable. Just wash your hands/don't lick the lead and you'll be just fine. The ROHS solder is arguably worse for you because the flux fumes are considerably harsher and pose more of an inhalation hazard.

 

Nickel is a common component in jewelry, so I'm pretty sure that's a non-issue.

Yeah, even Silver/Merqury/Iodine etc. is pretty safe, sometimes even good for you in small doses.

[Kawaii Koneko]

On 5/11/2020 at 11:19 AM, ColinLTT said:

A pen --might-- work, but I doubt it. Be sure to report back! 

I sure will! Truth be told that after I made the post, I got distracted and forgot about it lol. I still need to order the pen. I see they have it on Amazon so it shouldn't take too long to get here.

 

On 5/10/2020 at 1:21 PM, boarder2k7 said:

This same thing happened to my first gen Galaxy Watch or whatever they called it. I was fortunately able to find a repair part from some obscure Chinese website, open the watch up, and replace the part, it was a separate sub assembly glued in from the back of the case, which also looks to be the case here.

 

There isn't any harm in trying a conductive pen, just make sure not to bridge anything. I think your only real long term solution is to find a repair part though.

I'm wondering just how long term of a solution that would be though. It seems this has happened to other users so I'm wondering if the replacement part will just wear out as well. I've had the watch for a couple of years and can see myself continuing to use it for quite some time because I really like the watch and haven't seen much that interests me in upgrading except for maybe better health monitoring.

 

Plus, the replacement parts I have found all are silver, no black ones seem to be available.

 

Anyway, even if I have to touch it up every several months, I'd be happy. It would only be a minor inconvenience.

On 5/11/2020 at 5:18 PM, boarder2k7 said:

As someone who worked for a year running board and wiring assembly with leaded solder, I can tell you that the talk of issues from leaded solder is highly overblown. I went through a LOT of solder, over a pound a month of Kester 60/40, and when I left that job I had my doctor run lead levels in my next routine blood work, and there was nothing detectable. Just wash your hands/don't lick the lead and you'll be just fine. The ROHS solder is arguably worse for you because the flux fumes are considerably harsher and pose more of an inhalation hazard.

 

Nickel is a common component in jewelry, so I'm pretty sure that's a non-issue.

I was a little worried about the lead to be honest but I decided to try it anyway. Unfortunately, I couldn't get the solder to bond to the contacts. I'm not sure if there is a trick to this or not. I've soldered on circuit boards before and never had an issue getting the solder to bond so I'm not sure what the deal is here. I'm not an expert at this or anything, just capable enough.