clean coating from PCB

[aurgathor]

I took apart a UPS, and the PCB, including a significant portion
of the components on it are coated with some kind of clear and
shiny lacquer. This is nice for some things, but now I can't read
the markings on the chips. What kind of cleaner is best to clean
the coating from the chips?

TIA,
aur

 

[philo]

I took apart a UPS, and the PCB, including a significant portion
of the components on it are coated with some kind of clear and
shiny lacquer. This is nice for some things, but now I can't read
the markings on the chips. What kind of cleaner is best to clean
the coating from the chips?

TIA,
aur

i'm sure this will work

http://www.mgchemicals.com/products/8310.html


but i'm also sure it'll be toxic as hell
so be sure to use it in a well ventelated area or outdoors

 

[William P.N. Smith]

I took apart a UPS, and the PCB, including a significant portion
of the components on it are coated with some kind of clear and
shiny lacquer. This is nice for some things, but now I can't read
the markings on the chips. What kind of cleaner is best to clean
the coating from the chips?

I'm not sure that it's supposed to come off, and any solvent that will
remove it will probably tear the {markings, epolxy bodies} right off
thise chips...

 

[Guest]

I think its called conformal coating and a real beast to try any repairs, I
inspected them and when the vendor repairs them they really look bad and
unreadble!!!
timba

 

[aurgathor]

Guess what, I figured I'll just try all my applicable household
chemicals starting with the mildest one (Isopropyl Rubbing
Alcohol), and I hit the jackpot right away!

A cotton swab dripped with rubbing alcohol plus a bit of
rubbing followed by wiping with dry toilet paper works
like a charm on this particular type of conformal coating.
(I only cleaned the top of the ICs so far)

I wonder if it's acrylic or urethane based, (based on one of
the posted link) and what does it going to do if I heat it up.

BTW, I found a bunch of comparators, some Schmitt triggers,
a PWM conroller, and a quad AND gate. Appears to be a
fairly trivial circuit.

Thanks for the links and the follow-ups.

 

[EN]

The clear coating is called conformal coating.
I guess you've found out that there are different kinds of conformal
coatings,
silicone and urathanes. I have used Zip-Strip, a paint stripper, and it
'does not'
remove any markings from the IC's. The conformal coating bubbles up.
Use running water to wash the board off.