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Old 9th December 2017 | Show parent
  #8
Quote:
Originally Posted by dahleylama View Post
was over at cake...
Welcome!

Quote:
Originally Posted by dahleylama View Post
Im curious if my black goo looks a whole lot 'cleaner' because of the light use or if the black goo issue is a problem that is isolated to a particular batch of black goo they used in manufacturer.
I noticed that as well. It could very well be a better batch of the BGOD.

Quote:
Originally Posted by dahleylama View Post
The resistor is the only thing that I can see that actually looks suspect (see pictures). No bulging caps that I can see.
Which resistor? The one in the center near the red wire? Yes, that one looks like it could be cracked? Do you measure 2k ohms?

Oh wait, I see the one you're talking about! Yes, that dude is scorched, but it can also just be the external appearance. The internal carbon, resistive element may be okay. Looks like it should also be a 2k ohm resistor.

Quote:
Originally Posted by dahleylama View Post
How did you get the black goo off without taking of the components? I want to use a solvent, but I have read that epoxy removing solvents can also affect traces on the board. However, it looks like there are no traces? Only jumpers???**Edit, looks like the green could be traces?
Yes, the dark green lines are the traces. PCB manufacturers coat copper-clad boards, which are typically fiberglass, with a conformal coating which stops corrosion, oxidation, and also doubles as a solder mask.

And the BGOD is only destructive (as it is conductive where it shouldn't be) where it coats exposed electrical connections such as jumpers, between solder joints, or across leads of a component.

Quote:
Originally Posted by dahleylama View Post
Can I just dip this thing in a tub of epoxy remover solvent?
I wouldn't do that. You risk just making a mess out the entire board. I would single out areas that could be problematic, as mentioned above. Then take an X-Acto blade and carve it out. You can also do the old-school hot flat-tip screwdriver (or hot X-Acto blade) technique, i.e. heat the screwdriver over a flame. I've found that heat was the most effective. You honestly don't need to get rid of it all, just the areas where it could conduct electricity used in the power rails and low-level audio signals.

Quote:
Originally Posted by dahleylama View Post
Also, the fact that both my LF and HF drivers are not working, this must rule out or narrow down the area where I need to target. Any ideas?
I don't like the looks of the goop near pin 1 of the HF amplifier (the left IC) where the black wire connects. Looks like the goop could be spanning over a few components.

Also near BOTH suspect resistors. The goop is spanning across the leads of the center resistor and the jumper. This is a big problem area. And the scorched-resistor-area needs to be cleaned up.

Don't worry about the area under the capacitors. Most likely, if the goop has a "lip" to it, then it did not flood underneath the caps. Knowing PCB manufacturing processes, the goop should have been added after board population.