Should something be done about these traces?

[HyKlas]

Not broken or anything, just heavily corroded. This is an ARC D-115 mkii by the way... The underlying copper is fine no doubt but there had to be some reasoning behind tinning the traces vs applying solder mask.

This unit has a weak channel on the side that is corroded. New tube sockets are on order as some are loose. This also may have weakened an output or two due to intermittent arcing but I have no way to test. Once the new sockets arrive I'll swap tubes to determine if the weak one follows.

Be that as it may, we're getting off track here. Should I attempt to reflow these or just leave them as is? I've tried fine abrasives like a pencil eraser and a light lashing with Brasso on a q-tip with no luck. If not reflow, something else? Thanks all...

 

[Sch3mat1c]

Poor thing looks like it needs to be taken out and scrubbed...

Or sandblasted...

Old boards were made with tin everywhere, for whatever reason because they didn't have solder mask as it is today.

Tim

 

[lexx21]

It' dirt, not corrosion. Years of dust. You could blow it out with an air compressor, but other than that I would leave it alone.

 

[JonSnell Electronic]

Many years ago, when I was an Engineer for Rediffusion Television Rentals, we used to wash the boards in warm water and scrub them with an old toothbrush. When clean, place them in a warm place to dry thoroughly and then bake them in an oven at 90degrees C for a couple of hours. That brings them up like new.

 

[HyKlas]

It's most definitely corrosion. That corner of the amp has some of the cage pegs rusted and snapped off in the chassis. If Brasso doesn't remove it, it's not grime. Sure there is a film of crud from the moisture mixed with dust but the solder is being eaten away and quite a few of the component leads have that lovely green build-up on them. The bottom panel is also rusted in that spot and will need to be blasted.

With that said, should I just wash this board and leave it be or give it a more severe treatment like attempting to reflow the corroded traces? I'm already going to have the board out to recap, replace the level pots, and throw on some new i/o terminals.

Thanks a bunch guys.

 

[DeathRex]

Parts of it look like the board needs replacing. You can try reflowing, might need a lot of flux. But if the fiberglass has corrosion in it, it might start arching afterwhile.

 

[dgta]

I would try solder wick to get most of the tin off the traces and see what it looks like after that and a good cleaning.

 

[HyKlas]

It won't melt, even at 750°... Was able to wick a little, most likely from the outside edges, but nothing comes up from the corroded bits. Can't get the solder around the components to melt either. Seems I may be on a suicide mission.

I'll still attempt the sockets since they're soldered to the underbelly but I have little hope in this amp ever being reliable. I think DeathRex got it right when he said the word "replacing"...

 

[DeathRex]

I got some TVs in the shop that had a slight bit of water damage, where a plant on top leaked inside and it looked like that. I couldn't clean off the corrosion with solder. I thought 750 deg would burn it off, but it didn't. You would have to scrape it all off, but if it go into the pcb, the fiberglass could turn into a resistor, with enough voltage, it would burn through. Luckily your components can be saved, except might need to replace the multiturn pots.
Looks like a board you can make yourself with a sharpy or paint the traces.

 

[lexx21]

Before you do anything, rub a qtip on the traces and see what comes up. That will tell you if it dirt or not. Might save you some time and effort.