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Old 01-03-2001, 11:09 AM
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Join Date: Dec 2000
Location: AL
Posts: 1,219
Hi all,

I've noticed many posts where people speak of resoldering the connections on the circuit boards of their cruise amps. Since my cruise control was suffering from occasional confusement, I decided it was time to resolder mine. I removed it from the car and opened it up. I slid the card out and noticed it looked like it had been dipped in some sort of clear paint when new. The coating is very thick. I find it impossible to resolder the joints because of this coating. When I try, the solder just bubbles under the coating and then pulls up from the board. Even applying new solder, I can't get it to melt onto the board; it just won't stick.

How are ya'll getting around this?

Michael Brewer

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Old 01-03-2001, 05:21 PM
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Join Date: Jan 2000
Location: New Bedford, MA USA
Posts: 1,583
Michael, soldering approaches being an art form. To do it correctly w/o making the damage you're trying to fix worse, requires a lot of patience. The coating is there to seal the pc board traces from moisture and corrosion. There are a couple of ways to remove this coating. Least destructive is to use q-tips dipped in acetone or laquer thinner and rub the areas you want to wwork with. The least desirable way is to sure a sharp object and scrape the coating off. But,, on a cruise amp board, you will be doing a lot of scraping. Don't overheat the traces, or they will lift off of the fiberglass substrate. Be careful and you will be able to get this job done..
Jeff Lawrence
1989 300e
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.
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Old 01-02-2004, 12:03 PM
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Join Date: Dec 2000
Location: AL
Posts: 1,219
OK, I can't get this coating off.

I've tried acetone, laquer thinner, paint remover and denatured alcohol. Nothing will dissolve it that I've tried so far.

This board was dipped in something when it was new and it is intended to stay!

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Old 01-02-2004, 03:13 PM
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Join Date: Oct 2002
Location: Near Raleigh, NC
Posts: 580
The coating is varnish, it should come off with acetone. Take your time.
I know of people who have submerged it in acetone for an hour, and it just dissolves (I would not try that).
I tried the resoldering technique, but it did not work for me. I ended up buying a used amplifier (it worked right from the get go)
1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
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Old 01-02-2004, 07:17 PM
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Join Date: Jul 2002
Posts: 1,141

You do not need to add additional solder. The reason ppl do this is to get new flux on the joint so the solder will flow. You can buy some special flux- I suggest RMA flux for $2-3.

Yes, remove the coating first.

Clean post soldering with alcohol to remove flux.


Michael McGuire
83 300d
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD
86 300E
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