Doug Gennrich

I would like to re-solder my cruise module on my '87 auto.

My question is how do you remove the "plastic" coating over all the solder joints or do you just try to solder through it?

ROG100

Some say you are supposed to remove it, however I resoldered without doing so and it worked fine.
Done three so far and all succesful.

SharkSkin

I used Berryman's B-12 chemtool. Be very careful to keep it off of the components on the back side of the board. You'll also need a stiff plastic brush.

H2

I carefully scraped the coating off after loosening it with something but I don't remember what it was...and don't dare guess in case I'm wrong.

Harvey

ROG100

Why would you take it of if resoldering works without doing it?
What does it do in the first place?
Interested in the answer.

macreel

Roger... that 'film' is a conformal coating, probably
(polyvinyl alcohol) PVA. It is used by circuit board
makers to protect against damp, moisture, fungus,
dust, etc. It also gives some vibration protection
too. Reliability, you see.

Some of our Boeing electronics/avionics use a coating
so tough you need a sawzall to get through it. Nearly.

G'luck.

ROG100

So why take it off?

macreel

Some vendors apply the film to both sides of the board, i.e.
over the solder on the 'backside' (doesn't apply to my board,
nor yours, apparently) (some use a 'lacquer')
so must remove it to resolder. Sometimes a component must
be removed/resoldered so must remove it then on the 'front'
side. oh, a disturbed film shows that it has been tampered
with, so warranty is out the window. Not our problem, eh?

Depends. If you don't need to get through it leave it be.


G'luck.

SharkSkin

Roger, at least in my case, I could not solder with the coating in place. I did try, hoping that I wouldn't have to strip the coating off. Either my iron wasn't hot enough or it's a different coating. I wouldn't want to use a hotter iron though, that carries additional risk.

ROG100

Hi Dave,
I used a fairly low wattage iron. The coating did not seem to give me a problem.
I tended to concentrate on the moin soldering points closer to the connection point to the wiring loom and that did the trick.
All so far have come back to life perfectly.
Thanks,
Roger

H2

If your method works, don't mess with it. The guys here in the electronics shop tell me that if you don't take it off it can mess up solders. Obviously, this is not always the case.

Harvey

Steve J.

That sounds encouraging. Mine has never worked. Think I'll try this. Where is the cruise brain located? Where is the "tempostat" covered in the WSM?

macreel

Steve J... cruise brain is under central console, between radio
and firewall, bolted to tunnel. One connector to undo. Remove
passenger map shelf and console panel. WSM vol.1A, sect.27


G'luck.

Doug Gennrich

Sounds like I will try without removing the coating first and see if it works.

Thanks for all your help!!

Andrew Schauer

Denatured alcohol took the coating off my 1980 cruise control brain board. Also used a stiff brush like Dave.