Is it just me or is this a terrible PCB? - Page 1
Forum section: electronics / general

author: WyverntekGameRepairs
author_rank: Regular Contributor
timestamp: December 28, 2019, 01:55:15 am
content: I was repairing a cheap crappy 3rd party SNES controller (surprise surprise, it was from China), and when I opened it up, I saw what had to be the most sloppy and disgustingly contaminated PCB I’ve ever seen. The stuff on the PCB is NOT dirt, it is actually in the PCB itself. Is this considered a “bad PCB?”

author: Rerouter
author_rank: Super Contributor
timestamp: December 28, 2019, 02:40:26 am
content: without seeing the other side hard to say, but looks like FR2, which is a little cheaper in bulk,

author: jpanhalt
author_rank: Super Contributor
timestamp: December 28, 2019, 02:51:32 am
content: Quote from: WyverntekGameRepairs on December 28, 2019, 01:55:15 amIf it was in a damp environment, it could be a mold/fungus.

author: ataradov
author_rank: Super Contributor
timestamp: December 28, 2019, 02:56:25 am
content: So PCB is a bit dirty? Who cares? Your product is not going to be judged based on the quality of the PCB, except by a few snobby experts.I bet it came this way from the factory. It is manufactured to a price, so you can't expect perfection.

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: December 28, 2019, 04:57:48 am
content: By the way, what causes those weird circles at the farm down the road? Looks like the farmer stakes a goat to a different part of the field each day.

author: digsys
author_rank: Unknown
timestamp: December 28, 2019, 05:55:13 am
content: If it isn't populated with high density / or tiny SMTs on the other side, then it very likely doesn't matter. Likely just used as a "place holder" for connections etc,possibly a sensor as well. It is much easier to fabricate things like that on pcb material than having to do a sheet-metal etc run.

author: jpanhalt
author_rank: Super Contributor
timestamp: December 28, 2019, 10:07:18 am
content: Quote from: I wanted a rude username on December 28, 2019, 04:57:48 amThey are called "Fairy Rings" and are also caused by a fungus. The mechanism is quite interesting.

author: WyverntekGameRepairs
author_rank: Regular Contributor
timestamp: December 28, 2019, 04:49:30 pm
content: Quote from: blueskull on December 28, 2019, 10:12:53 amEw, that is quite nasty. Yeah, I don’t think I’ll want to stoop that cheaply in my own designs - I’ll stick to JLCPCB.Wouldn’t that have been rejected for shipment though due to the organisms inside of the substrate? I’d imagine it would have not passed biological screening.Anyway, thanks for the helpful answer. I appreciate it now knowing that the PCB could have mouldy substrate. Yeck.

author: jpanhalt
author_rank: Super Contributor
timestamp: December 28, 2019, 05:22:55 pm
content: Actually, it may not (I suspect probably not) be due to the manufacturer but to the user. You will find mold/fungus growth frequently on phenolic-paper PCB's (FR2) that are kept in warm damp environments, like basements and tropical/subtropical climates.

author: ataradov
author_rank: Super Contributor
timestamp: December 28, 2019, 05:42:41 pm
content: Quote from: WyverntekGameRepairs on December 28, 2019, 04:49:30 pmAt your virtually non-existent volumes you won't get any benefits from using cheaper materials anyway.And I seriously doubt it is actually mold or any sort of organic substance.Have you tried to rub it with alcohol? Does it come off or is it in the top layer?

author: WyverntekGameRepairs
author_rank: Regular Contributor
timestamp: December 29, 2019, 02:30:42 am
content: Quote from: ataradov on December 28, 2019, 05:42:41 pmYes, I attempted to scrub the yeck off. No luck, it is actually inside the substrate.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 29, 2019, 03:44:17 am
content: Quote from: jpanhalt on December 28, 2019, 10:07:18 amHm I don't know about that, shouldn't they be greener inside or something?Tim

author: james_s
author_rank: Super Contributor
timestamp: December 29, 2019, 06:01:43 am
content: Looks like a phenolic PCB, they used to be common in cheap stuff, I've seen a lot of them that looked splotchy, I always figured it was just randomly colored fibers, possibly recycled material that gets pressed into the board. Who cares though? It's a cheap PCB in a cheap piece of gear, a nice looking FR4 board would have cost more and very few people would ever see it. At least 99.99% of consumer devices go from the factory to the landfill without anyone ever looking inside them.

author: Siwastaja
author_rank: Super Contributor
timestamp: December 29, 2019, 01:38:55 pm
content: Quote from: T3sl4co1l on December 29, 2019, 03:44:17 amI tend to look for these rings caused by the fungusMarasmius oreades, because it's edible and actually very tasty, one of the better mushrooms. You can find them from far away by recognizing the rings. Sometimes the rings are of deeper green shade than the surrounding grass, but sometimes, it seems to reduce the grass growth instead, leading to the brown look of the soil.But this might be something else. They are of too uniform size, I think.Of course, like many other delicious fungi, they are said to collect poisonous heavy metals from contaminated soil, so limitation of intake may be a good idea, especially when they grow at a polluted site with a lot of traffic pre-1990.