Is This Circuit Board Corroded?

[Frank77]

The number of items with dried blood inside them when you take them apart is shocking. I used to find it regularly in brand new PC cases. Found it inside a toaster, as well. Fun to see how the items we take for granted are actually built.

Oh, there are definitely traces of my blood in some lab equipment around the world (previous job was assembling / testing electronics). That pesky sharp metallic adhesive EMI shielding, am I rite?

Other suggestion for the OP: If the pedal works as expected, you could also do nothing and close it back up. Flux residue like this rarely cause any issue other than cosmetic and should not have any functional impact. The only time I've seen something happen due to flux was the result of a much more important and sticky buildup inside a connector. I'd be more concerned by loose balls of solder if there are any (can't tell from the picture). If that's the case, just brush them off from the PCB and close the pedal back up.

 

[jblock]

Not the cleanest job. Probably soldered on a Friday afternoon. End-of-day/shift manufacturing can be a wild card!

 

[dxb]

Thanks for all the replies. It sounds like the consensus is leftover flux that someone didn't clean off. I'd initially guessed corrosion because it resembles the crust on a leaky battery. Also I hadn't seen residue like this in any of my other pedals.

Anyway, it sounds like the gunk can be removed with rubbing alcohol, which I'll try if I decide to keep the pedal. I'm on the fence though. Its double-stacked pots are hard to get a hold of and the position markers are difficult to read. I've also struggled to get usable tones as most combinations just produce 'broken speaker' style fuzz. The ringmod sound is okay when everything is set just right but its somewhat limited.

Also, the pedal gets hot after a while, even when disengaged. Maybe its because its 18v but I don't recall other non-tube pedals heating up like that. In fact, the manual specifically mentions not leaving it plugged in...

"To turn the device off, un-plug it from the wall or turn off the power going to the 18VDC supply. We recommend that you do not leave your Ringmaster powered up for long periods of time when it is not in use."

 

[byacey]

Looks like flux on the hand soldered components.
Lots of “new” flux — been out for about 20 years, is more environmentally friendly.
Some are water soluble, but can be cleaned with alcohol.
Old school flux usually leaves yellowish residue.

How much more environmentally friendly can rosin flux be? It's made from pine tree sap.

 

[Slevage]

How much more environmentally friendly can rosin flux be? It's made from pine tree sap.

It’s the cleaning solvents that come into question. The EPA wants to know what’s going down the drain and into the air.

 

[byacey]

Ethyl alcohol is probably the least harmful solvent for rosin flux. If you can drink it, how harmful could it be? It's when you start using chemically produced fluxes and solvents when the risk level goes up. Plain old rosin and spirits of wine have been used for centuries for various different purposes.